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LECTURE 1 – STRESS & COGNITION What is stress? Stress arises when individuals perceive that they cannot adequately cope with the demands being made on them or with threats to their well-being (Lazarus, 1966). It is a negative response. It is a physiological and psychological response when encountering a threat that we feel we do not have the resources to deal with. It is a perceived threat and involves a perception of being unable to cope. It is very subjective and transactional (involves the person & environment). What is acute stress? It is a short-term, intense physiological and psychological response to a specific and immediate stressor. It is a normal and natural reaction that can help individuals cope with a sudden threat. It is typically time-limited and resolves once the stressor is removed. What is chronic stress? It is a prolonged and continuous state of stress that persists over an extended period resulting from ongoing, repeated, or unresolved stressors. It can have significant negative effects on physical and mental health. Leads to prolonged release of stress hormones like cortisol. What is a stressor? A stressor is a perceived threat versus the response to the threat. What are stressors? They can be minor or major. Acute or chronic. What are the two main stress response systems and what controls it? The hypothalamus controls the two main stress response systems: 1. The sympathetic adrenal medullary (SAM) axis – adrenaline 2. The hypothalamic pituitary adrenal (HPA) axis – cortisol Together, these systems regulate the stress response. When they become overworked (chronic stress), they can malfunction and bring about ill health. What is the stress response? 1. Perception of a stressor. 2. Amygdala processes emotional significance of stressor and hypothalamus signals the body to prepare for a response. 3. Hypothalamus triggers release of stress hormones (adrenaline and cortisol) from adrenal glands. 4. Adrenaline stimulates the SNS which causes immediate physiological changes such as increased heart rate. Airways in the lungs dilate for more oxygen. 5. Cortisol increases blood sugar levels for energy. 6. Non-essential functions are temporarily suppressed. How does stress effect memory? Stress may impair memory because you are less likely to remember irrelevant information as you are just trying to survive. However, if there is a specific threat to your health and safety, you may remember something relevant such as past traumatic memories. Threats can also give you PTSD. What is stress like in modern society? Stress accounts for 37% of all work-related ill health cases and 45% of all working days lost due to ill health. There appears to be more stress in public sector organisations. Mental Health Foundation (2018) claimed that 74% of UK adults have felt so stressed at some point that they felt overwhelmed or unable to cope. How does the HPA axis work? 1. SCN in hypothalamus (located above brain stem) senses stress and releases a hormone called corticotropin-releasing hormone (CRH) into the portal blood vessels of the pituitary. 2. CRH stimulates the pituitary gland which then releases adrenocorticotropic hormone (ACTH) into the main blood system. 3. ACTH signal to the adrenal glands to release stress hormones. 4. There are two adrenal glands, one on top of each kidney. In response to ACTH, adrenal glands produce and release stress hormones. Adrenal cortex releases cortisol (glucocorticoid) which travels everywhere including the saliva. Adrenal medulla releases adrenaline (epinephrine) which prepares body for fight or flight. These hormones prepare the body to respond to stress by increasing energy production, enhancing alertness, and suppressing non-essential functions. What is cortisol? Cortisol is ESSENTIAL for life but should be properly regulated to maintain overall health. Chronic stress is associated with prolonged periods of excessive cortisol secretion and enlarged adrenal glands. 1. Cortisol increases blood sugar levels and provides energy. 2. It has anti-inflammatory properties. 3. It can affect metabolism and regulate BP. 4. It suppresses non-essential functions temporarily. What are high cortisol levels associated with? Stroke, depression, high BP, angina, heart attack, diabetes, osteoporosis, accelerated cancer, and HIV progression. They are also associated with poor physical and mental health and memory. Elevated cortisol levels can also impair the function of the hippocampus which can lead to memory problems. How can cortisol be measured? It can be measured in saliva using the SALIVATTE and cortisol concentrations are often determined using ELISA assays. What are the information inputs for orientation? Visual, vestibular (inner ear) and proprioceptive (somatosensory); some minor ones are: auditory and olfactory (smell). What is the processing of orientation? The relative importance between sensory inputs may vary between individuals for instance, in the dark, visual inputs are useless so vestibular and proprioceptive are given greater weight. Some people are field dependent. What causes angular movements? Semi-circular canals. What causes transitional (linear) movements? Otoliths in utricle and saccule. What are the functions of the vestibular system? Spatial orientation, balance, standing, walking, stabilising vision (vestibular ocular reflex VOR), motion sickness (poison detector back-up system), vestibular-cardiovascular reflexes help regulate blood pressure. What is the vestibular ocular reflex? It is a reflex in which the motion of the head is sensed by the vestibular apparatus of the inner ear (semi-circular canals and otoliths). The information provided by these motion signals are then used to initiate ocular muscle contractions to move the eyeball. Gap junction in the vestibular system transmit signals faster than normal synapses. What are some clinical problems associated with the vestibular system? Minor imbalance, vertigo or dizziness: usually revolves spontaneously and may be caused by toxins or viral infection. Benign positional vertigo: caused be detached calcium crystals (otoconia) activating hair cells, can be cured by physical therapy. Vection: the illusion of self-movement in the absence of actual movement of the body. LECTURE 2 – PSYCHOBIOLOGICAL ASPECTS OF COGNITIVE NEUROSCIENCE What is behaviour? Behaviour refers to the actions, reactions or conduct of an organism in response to stimuli or situations. It is the way in which an animal or person behaves in response to a particular situation or stimulus. What is psychobiology? The study of the biological processes that underlie our behaviour (including emotion and cognition). What is cognition? The processes which underpin our thought process, our experiences of the world and how we interact with it. What is neuropsychiatry? It understands mental health by exploring neurotransmitter functions, carrying out neuroimaging, involved in cognitive neuropsychology and neuroendocrinology. It encompasses mental health conditions, neurodevelopmental (ADHD, autism) and neurodegenerative conditions (Alzheimer’s, Parkinson’s). What techniques are used for testing in neuropsychiatry? Psychometric testing is used for diagnosis and for monitoring interventions, techniques include self-report questionnaires or interviews, cognitive tests or observation, physiological examinations. What is cognitive neuroscience? The study of how the brain (function) and nervous system (neurotransmitters) interact with behaviour. Seeks to understand the precise nature of how we think and learn and how this links with the chemistry and structure of the brain. Why is cognitive neuroscience relevant? Sheds lights on the factors that influence the physical features of the brain. Helps us to identify ‘core cognitive components’ in any given task. Allows us to explore how things are related. What is cognitive testing? It assesses patterns of strength and weakness. It is used to identify damaged structure or pathways in the brain. It measures positive and negative effects of interventions such as drug treatments. What is the use of cognitive profiling in ADHD? It assesses impairments in ‘executive function’ and changes in fronto-striatal circuitry. Understanding of these leads to better understanding and management as well as potential pharmacological input. What is the use of cognitive testing in Alzheimer’s? Cognitive testing is a crucial element of all drug trials, it tests global function, memory and executive function. What are cognitive processes? They are the mental activities and operations that our brain and mind use to acquire, process, store and use information. Some key cognitive processes are perception, imagery, executive function, learning, problem solving, emotion, language. What is a neurone? Specialised cells that transmit information within the nervous system. Neurones communicate with each other and with target cells at junctions called synapses. They general electrical signals called action potentials that allow for the transmission of signals. How has brain capacity changed? 3.5 million years ago, brain capacity was 600 cc and now it is 1400 cc. Explain the evolution of the human brain. At the earliest stage, simple organisms had a cluster of never cells to respond to basic stimuli. As animals evolved, they developed bilateral symmetry and the ganglia emerged. Vertebrates went on to develop a CNS with a spinal cord. Humans have experienced cultural evolution which has influenced brain development through learned behaviours, tools, and cultural practices. This has allowed for increased brain plasticity. Variation -> larger brain -> more ideas -> more efficient tools -> more control over environment -> population successful. How does brain size increase during infancy? The foetal brain weighs about 250g. After birth, the brain weighs 335g. At 18 months, the brain weighs 1024g. One of the key processes in brain growth is neurogenesis, this starts in the embryonic stage until early postnatal period. Synaptogenesis occurs which allows the neurones to communicate and build connections. The infant brain possesses a high degree of plasticity. The neurones that do not get used are lost. So, the number of neurones decreases after birth, but the brain size increases due to synaptic connections. What are the lobes that the human brain is divided into? 1. Frontal lobe: thinking, memory, behaviour, and movement. 2. Temporal lobe: hearing, learning and feelings. 3. Parietal lobe: language and touch. 4. Occipital lobe: sight. 5. Cerebellum: balance and coordination. 6. Brain stem: breathing, heart rate and temperature. What is topographical organisation? Refers to the spatial mapping of sensory information or motor control within a particular area of the brain or NS. Adjacent areas in the brain or NS correspond to adjacent areas in the body. Sensory homunculus: the area of the sensory cortex that represents the fingers is larger than the area that represents the toes. Motor cortex: located in the precentral gyrus, the amount of cortical space allocated to a body part is proportional to the precision of movements in that body part. What is the timeline of the evolution of the brain? * 1. Aristotle: ratio of brain size to body size is greatest in most intellectually advanced species. 2. Galen: observed brain injury in gladiators, noted that nerves project to and from brain. 3. Gall & Spurzhein: phrenology, also noted differences between white and grey matter and folded nature of brain. 4. Purkinje: first nerve cell described. 5. Broca: function is localisable; language is a function that can be damaged separately from other processes. 6. Lichteim & Wernicke: language can be subdivided into speech recognition, speech production and conceptual knowledge. 7. Penfield: localisation investigated via electrical stimulation. 8. Berger: EEG developed. 9. Hodgkin & Huxkey: action potential discovered. 10. 1950s: emergence of cognitive psychology. 11. 1960s: emergence of neuropsychology. 12. Hounsfield: develops CT imaging. 13. Lauterbur: develops MRI imaging. 14. Reivich: PET 15. Barker: first study of TMS. What is transcranial magnetic stimulation? A non-invasive neurostimulation technique that uses magnetic fields to induce electrical currents in specific regions of the brain. Involves placing an electromagnetic coil on the scalp which generates magnetic pulses that pass through the skull and into the brain. These magnetic pulses depolarise or hyperpolarise neurons, leading to changes in neural activity in the targeted brain region. What effects our behaviour? Sleep (brain fog), diet (sugar), geography, light (SAD), trauma, relationships, education, neurogenesis. What are the effects of age on health? A higher subjective age is a powerful predictor of depression, diabetes, cognitive impairment, vulnerability to stress, higher systematic inflammation, weaker bones etc. What is the microbiome of the gut linked to? Imbalance (dysbiosis) is linked to psychiatric conditions such as depression and anxiety (gut- brain axis) as well as compromised cognition and myelination of the prefrontal cortex. It is affected by diet, stress, genes, and birth. What is the link between inflammation and psychiatry? Inflammation is the natural defence response of the immune system against environmental insult, infection, stress, and injury. How does chemistry affect behaviour? Imbalances in serotonin can contribute to mood disorders. Tryptophan is an essential amino acid and a precursor for serotonin synthesis, depletion of tryptophan caused negative mood alterations in Bell et al’s (2001) study which suggests the effect of dietary interventions on mood. Caffeine and alcohol have everyday effects. Psychedelics lead to altered state of consciousness. Studies have suggested that the hormone oxytocin can enhance social behaviour in some with autism, it also has anxiety-reducing effects. What is significant about neurone connections for autism? Reduction in global connectivity but increased activity in local networks. What is significant about neurone connections for schizophrenia? Strength of functional connectivity decreased but diversity of connections increased. What is significant about neurone connections for traumatic brain injury? Sharing of white matter tracts, inflammatory responses, and disrupted neurotransmitter release. What did Kavita Vedhara find out? She worked with 138 people who were due to get vaccinated for influenza. It was found that participants who were in a good mood on the day of the vaccination exhibited a better response to the flu shot. Is the useful links for additional reading essential for exams? LECTURE 3 – Stress, Arousal & Circadian Rhythms There are some images in this PowerPoint that might need memorising. Need to read articles posted under Lecture 3. There are also some images in seminar 3! What is a circadian rhythm? It is an internal process that regulates the sleep-wake cycle which is controlled by the body’s internal biological clock which is located in the brain (hypothalamus) and is influenced by daily patterns of light and darkness. These rhythms are influenced by external cues such as light and temperature. They also influence other bodily functions such as hormone production, body temperature and metabolism. What is the natural process of the circadian rhythm? Early morning: deep sleep, body temperature trough (4:30 am), melatonin levels decrease, cortisol levels increase (3 am). Awakening: cortisol peak (8:30 am), cortisol awakening response. Early afternoon: high alertness, no melatonin, cortisol levels gradually decreasing. Evening: peak muscle strength (5 pm), body temperature peak (7 pm), melatonin levels increase, cortisol trough (12am). What is the circadian system model? INPUT: Light, input pathway resets the clock. Input is detected by retinas and transmitted to SCN through retinohypothalamic tract. OSCILLATOR: The central pacemaker (SCN) that generates the oscillation after receiving input from external cues. OUTPUT: The output pathway that translates the oscillation into behavioural and physiological rhythm. What is endogenous rhythmicity? The circadian system is able to maintain a rhythmic pattern even in the absence of cues. What is daytime in the circadian rhythm? Diurnal. What is night-time in the circadian rhythm? Nocturnal. What happens to body temperature at night-time? It drops significantly lower. How is the circadian rhythm reset? Circadian rhythm is self-regulating BUT light is required to reset it. A stimulus that resets the biological clock is known as ‘zeitgeber’ (time giver) and this can be factors like light, tides, noises, meals, social interaction, and temperature. In humans, light is the primary zeitgeber. Why is it important for the circadian rhythm to be able to reset? To allow flexibility and adaption to different time zones and seasonal changes. This adaption does not happen instantly and takes time. What is the suprachiasmatic nucleus (SCN)? It was discovered in 1972 that the biological clock is located in the SCN (part of the hypothalamus). It is a small region, tightly packed with neurones, dendritic synapses, some neurones are clustered around capillaries (neurosecretory. They control other parts of the brain via neural pathways and secreted neuromodulators. SCN serves as the body’s master clock or central pacemaker. It receives direct input from the retinas which helps to reset the circadian rhythm. The SCN then generates input that influence other hypothalamic nuclei controlling the release of hormones like melatonin from the pineal gland. Other tissues and organs have their own internal clocks (peripheral clocks), the SCN helps synchronise these peripheral clocks to maintain overall circadian coordination. What can disruption of the SCN lead to? It can cause severe disruption to the circadian rhythm affecting sleep patterns, hormone release and other physiological functions. Where is the SCN located? It is located in the hypothalamus right above the optic chiasm (the point where the optic nerves cross). It is strategically placed between the visual and the neuroendocrine pathways. The paraventricular nucleus sits right above the SCN, and it influences the HPA axis. Why is the proximity of the SCN to the OC significant? It is significant because the SCN receives direct light input from retinal ganglion cells that detect light, this is a crucial external cue for regulating the circadian rhythm. There are direct projections of fibres from the retina to the SCN via the retinohypothalamic pathway (there is also an indirect pathway called the geniculohypothalamic pathway which is important for non-light zeitgebers. These processes are mediated by a chemical called melanopsin. What is the circadian rhythm of cortisol secretion? Cortisol levels typically reach their highest point after waking, this surge is referred to as the ‘cortisol awakening response’. They gradually decline throughout the day, and it reaches its lowest levels usually around midnight to 4 am. What is the cortisol awakening response? It refers to the rapid increase in cortisol concentration within the first hour of waking, it peaks between 30-40 minutes. It is initiated by a hormonal cascade. It is sensitive to light particularly blue wave light, light exposure in the morning helps to synchronise the body’s internal clock with the external day-night cycle contributing to the appropriate timing of the CAR. It is also thought that earlier and greater CAR leads to better executive function in old age. CAR also predicts better executive function in general 45 minutes post awakening. A bigger CAR predicts more brain plasticity later in the same day. What is the role of the cortisol awakening response? It is believed to prepare the body for the challenges and demands of the day. Cortisol increase in the morning may help mobilise glucose and energy resources and enhance alertness. Does the cortisol awakening response help to inform peripheral clocks? Cortisol does tend to act as a signalling molecule, and it can help to synchronise peripheral clocks in various tissues and organs to regulate local circadian rhythms and contribute to the coordination of physiological processes. More specifically, human peripheral clocks are entrained by glucocorticoids which work to synchronise circadian rhythms of peripheral clocks with the SCN master clock. What other factors are peripheral clocks informed by? Hormones such as glucocorticoids and melatonin, neuronal connections, body temperature, metabolites such as glucose, paracrine signal such as prokineticin 2. What is a glucocorticoid rhythm? It refers to the natural, rhythmic pattern of release and circulating levels of glucocorticoid hormones in the body. Glucocorticoids are a class of steroid hormones and cortisol is the primary glucocorticoid in humans. The secretion of glucocorticoids follows a circadian rhythm, and the regulation of this rhythm is tied to the body’s internal circadian clock, particularly the SCN in the hypothalamus. What are the information inputs for human orientation? 1. Visual 2. Vestibular (inner ear) – consists of semi-circular canals which are 3 fluid-filled structures that detect rotational movement of the head and sense angular accelerations; utricle and saccule detect linear acceleration and gravity. 3. Proprioceptive (somatosensory) 4. Auditory 5. Olfactory (smell) Human orientation (sensory awareness) allows one to perceive and understand their position and movement in space. What happens to spatial awareness in the dark? Visual inputs are useless, so vestibular and proprioceptive inputs are given greater weight. Auditory and tactile information is also used. Some people are field dependent. What are the functions of the vestibular system? It is involved in spatial orientation, balance, standing, walking, stabilising vision, and the vestibular ocular reflex. Vestibular-cardiovascular reflexes help regulate blood pressure with posture movement. It is able to detect linear acceleration and deceleration and provides information about changes in speed and direction of movement. It also helps to prevent motion sickness. What is the vestibular ocular reflex (VOR)? It is a reflex in which motion of the head is sensed by the other vestibular apparatus in the inner ear (semi-circular canals detect rotational movement and otolith organs detect linear acceleration). The information provided by these motion signals is then used to initiate ocular muscle contractions to move the eyeball. Information is usually carried by the vestibular nerve from the inner ear to the brainstem, specifically to the vestibular nuclei. Gap junctions in the vestibular system transmit signals faster than normal synapses. What are some examples of clinical problems to do with the vestibular system? 1. Minor imbalance, vertigo, or dizziness – usually resolves spontaneously, may be caused by toxins (food poisoning, alcohol, or drugs) or viral infection. 2. Benign positional vertigo – caused by detached calcium crystals (otoconia) activating hair cells. May be cured by physical therapy. 3. Vection – the illusion of self-movement in the absence of actual movement of the body e.g., train moving on platform. LECTURE 6 – Addiction & Learning One image in this lecture may need memorising. What is a sensation? It is the stimulation of the senses: touch, sight, hearing, smell, and taste. What is perception? It is the interpretation of the acquired sensations (visual sensory information). It could rely directly on the information present in the stimulus or on the perceiver’s expectations and previous knowledge as well as the information present in the stimulus. Even though the stimulus is the same for everyone, how we perceive it differs depending on each individual. How must perception occur? In order for perception to occur, we need to have visual stimulation. Low level processing (bottom-up processing) involves the analysis of sensory information, it starts with raw sensory input with the brain receiving signals from the sensory organs to assemble them into a coherent perception without relying on prior knowledge or expectations. High level processing (top-down processing) involves the use of prior knowledge, expectations, and context to interpret sensory information, higher level cognitive processes such as memory guide the perception of the sensory information. What is addiction? It is a primary, chronic disease characterised by impaired control over the use of psychoactive substances and or behaviour. Clinically, the manifestations occur along biological, psychological, sociological, and spiritual dimensions. A caveat is that this disease is not pathogen based and it is non-transmissible; acquisition requires direct, voluntary action on part of the individual. What is learning? Any relatively durable change in behaviour due to experience. Experiences cause neurobiological change (changes to the brain, new synaptic connections, neural plasticity), these present as and are assessed through changes in behaviour. This can be seen in all animals, it is generally adaptive, there is an evolutionary basis. What is classical conditioning? A form of learning in which a neutral stimulus (has no biological meaning so a sound or a flash of light) that is paired frequently enough with a significant stimulus (food or pain) comes to elicit a reflexive response to the significant stimulus (salivation or avoidance behaviour). It is not a conscious behaviour; it is a reflex. They key components are: 1. Unconditioned stimulus (UCS): stimulus that naturally triggers an unconditioned response without any learning (drugs producing a pleasurable effect). 2. Unconditioned response (UCR): automatic, unlearned reaction to the UCS (euphoria when taking a drug). 3. Conditioned stimulus (CS): initially a neutral stimulus that through repeated pairing with the unconditioned stimulus comes to elicit a response similar to the UCR. 4. Conditioned response (CR): the learned, reflexive response to the conditioned stimulus. What are the stages associated with classical conditioning? 1. Acquisition and pairing: repeated pairing of a neutral stimulus (environment or cues) with the unconditioned stimulus (the drug) can overtime make the neutral stimulus become a conditioned stimulus evoking a conditioned response. So, if a person regularly uses a drug in a specific environment, that environment becomes associated with the drug use and can produce a reflexive orienting response or an anticipatory state. 2. Extinction: if the conditioned stimulus (environment or cues) is repeatedly presented without the unconditioned stimulus (drug), the conditioned response (craving or anticipation) may weaken. 3. Spontaneous recovery: the. Conditioned response may reappear in response to the conditioned stimulus after a period of time. 4. Generalisation: similar stimuli to the conditioned stimuli might also elicit the conditioned response (similar rooms might trigger cravings). What is cue reactivity? The repeated pairing of cues with the addictive behaviour leads to a conditioned response where encountering the cues alone can trigger a desire for the substance. Individuals experiencing cue reactivity are often more vulnerable to relapse when confronted with addiction-related cues, this heightened responsiveness may persist even after a period of abstinence making it challenging to maintain recovery. What is operant conditioning? It is a form of learning in which behaviour is strengthened or weakened by the consequences that follow it. They key components are: 1. Positive reinforcement: person engages in a behaviour (substance use) and experiences pleasurable effects; the positive consequences increase the likelihood of the behaviour occurring again. 2. Negative reinforcement: removal or avoidance of aversive stimuli, person might use substances to alleviate negative feelings such as withdrawal symptoms, the removal of these aversive states reinforces the behaviour. 3. Positive punishment: application of an aversive stimulus following a behaviour to reduce the likelihood of the behaviour reoccurring, person experiencing health problems due to substance use. 4. Negative punishment: removing positive stimulus to reduce the likelihood of behaviour, person might lose privileges due to substance use. What is the difference between operant and classical conditioning? Classical is measured with reflexes and are very deep responses over which you have no control over whereas operant is measured with voluntary actions that are under conscious control. What is the dopaminergic reward system? It runs from the ventral tegmental area to the nucleus accumbens (most drugs of abuse target these areas). The two areas are joined by the media forebrain bundle which is the main reward pathway. It goes out through the mesolimbic pathway which is associated with mood changes and euphoria. 1. Ventral tegmental area: contains dopaminergic neurones which release dopamine to the nucleus accumbens. 2. Nucleus accumbens: considered the brain’s pleasure centre and is associated with experience of reward and reinforcement, it is in the ventral striatum. 3. Mesolimbic pathway: connection between VTA and NA, processes rewarding stimuli and reinforces behaviours associated with pleasure. What happens if the reward pathway does not operate? You can experience anhedonia which is the inability to experience pleasure from activities that are typically rewarding, demotivation, depression, heightened vulnerability to addiction. What can a bolus dose of cocaine do? If you take cocaine the traditional way, you get cocaine solution resting on the mucous membranes and it just diffuses across slowly. It is weak and it mixes with the blood stream. However, if you smoke it or inject it, you get an immediate bolus dose of pure cocaine. Dopamine shoots straight up. The speed of the increase in dopamine is a predictor on how addictive a substance is. What is the evolutionary basis of reward? Humans have evolved to favour immediate over delayed reward so faster elevation of dopamine results in faster formation of the behaviour and thus, stronger reinforcement of the behaviour. Why do we get addicted to drugs? Reciprocal determinism which is a complex interaction between personal, behavioural, and environmental factors. LECTURE 7 – Nociception & Pain What is nociception? The neural process of encoding noxious stimuli. It is the detection of noxious stimuli in order to form an adaptive response to it and avoid it. What is pain? An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. You do not need tissue damage for pain to exist. it is a psychological state not a physical event. It is a complex phenomenon. What are nociceptive fibres? They are all afferent. 1. Large, myelinated fibres: A alpha and large C fibres (large diameter and high conduction velocity diameter). 2. Small, myelinated fibres: A beta (narrower with a lower conduction velocity diameter). They afferent fibres directly associated with nociception are: 1. A-delta fibres: smallest myelinated fibres. 2. C fibres: non-myelinated fibres, they are ancient and are free nerve-endings in the skin that act as thermoreceptors, they also respond to chilli, they are VERY small and have a very slow conduction velocity. What happens when you stub your toe? A-delta fibres (myelinated) mediate and cause FAST pain (shooting pain up the leg) and then the wave of SLOWER pain that is deep and dull is the C fibre mediated pain and it is much more diffusing and aching. What are the 4 cardinal signs of inflammation? Redness, heat, swelling, pain(hyperalgesia). When happens when tissue gets damaged? At the periphery, we detect a noxious stimulus (needle being stuck in arm). If it damages cells, it will produce bradykinin, serotonin, prostaglandin, and potassium (chemical cascade). C-fibres get triggered, and they trigger their neurotransmitter called Substance P which causes localised capillaries to dilate (blood rushes to the area causing reddening). White blood cells make fluid leak out to fight any infection (oedema), the area also feels warm. Substance P also causes localised mast cells to release histamine which causes the release of C fibres. Where do afferent signals go? Most afferent systems are a three-neurone pathway: periphery to spine to thalamus to different areas of the brain. All afferent signals come through the dorsal horns and leave via the ventral horns. What are the dorsal horns? They exist in layers called lamina. Lamina 2 and 3 is where a lot of pain processing happens (the substantial gelatinous side). Where do signals from LARGE afferent fibres go? Signals from the large afferent fibres synapse directly with projection neurones which further project up the spinal thalamic tract. A-delta fibre also acts in a similar way. BUT, C- fibres synapse with interneurons first THEN synapse with projection neurones to the thalamus. What is the spinothalamic tract? A bundle of sensory nerve fibres conducting afferent pain impulse up the spinal cord to the brain. A-delta and C-fibres come in through the dorsal horn and then they CROSSOVER to the other side and then ascend on the contralateral side and they do this in the spinothalamic tract. What is the FAST pain pathway? It is lateral. A-delta fibres come up the lateral spinal thalamic tract, the next major synaptic junction is in the lateral nuclei of the thalamus, and it projects directly to the somatic sensory cortex. Lateral system is responsible for sensation and the discriminative aspect. What is the SLOW pain pathway? It is medial. C-fibres come up the paleospinothalamic tract. They do not go straight to the thalamus; they go through the reticular activating system first. Eventually, they will project up the medial thalamic nuclei and will project around to a lot of limbic areas. Medial system is responsible for suffering, affective-motivational aspect. What is the anterior cingulate cortex? It is particularly important in pain because it is responsible for response selection. It is broken down into the anterior anterior cingulate (responsible for pain) and the posterior anterior cingulate (responsible for cognition). Activity in the anterior part inhibits activity in the posterior part which is why chronic pain is so bad because it is so constant and does not allow you to focus on anything else. What are the three dimensions to the experience of pain? 1. Sensory discriminative. (Deals with sensation, pain localisation, lateral pain system deals entirely with this). It includes the location, intensity, and quality of the pain sensation. 2. Medial division (affected-motivational). It involves the emotional response and motivational aspects of pain, the emotional distress and unpleasantness associated with pain. 3. Cognitive-evaluative: cognitive appraisal and interpretation of the pain, individual’s beliefs, expectations and coping mechanisms to pain are important factors. Lateral and medial systems function independently. The intense sensation from the lateral pain system becomes PAIN due to the medial pain system. These are the two basic components: lateral is purely sensory and medial is emotional, affective-motivational. What do CO2 lasers do? They trigger individual C-fibres in the skin. They trigger C-fibres because they produce heat. What factors influence between-individual differences? 1. Sex (depends on stimulus type) 2. Ethnicity/cultural affiliation: people learn, through social acquisition, ways of dealing with and expressing pain appropriate to their own culture, ethnicity is no longer a relevant factor. 3. Personality characteristics: strong-self efficacy and internal locus of control will lead to less suffering. What factors influence within-individual differences? 1. Situational factors (injury to finger will be worse for a pianist rather than for a builder). 2. Automatic evaluation: pre-attentive processing of salient features in the environment, people evaluate the valence of most, if not all environmental information which is why some people may feel uncomfortable in a hospital. Right amygdala signals for potential harm in the environment. AE is universal, unconditional, non-volitional and it is fast. What are the perceived benefits of incapacity? 1. Alleviation of obligations and responsibility. 2. Support and sympathy. 3. Physical assistance. 4. Possible financial gain. What are the perceived costs of incapacity? 1. Removal of obligations and responsibilities. 2. Loss of personal control and autonomy. 3. Possible financial loss. LECTURE 8 – Nature & Relevance of Memory What is STM? It is effortless but has limited capacity and fades quickly, it is prone to interference and delay. Information that is deemed important or relevant may be transferred from short- term memory to long-term memory through a process called encoding. What is LTM? It is reconstructive, limitless, and long-lasting. It involves episodic memory (recollection of events or experiences), semantic memory (general knowledge and facts) and procedural memory (skills and habits). How does amnesia differ in STM and LTM? STM memory generally appears to be preserved in people that have amnesia. Amnesia appears to effect LTM more which indicates that to some extent they are both separate processes. What is encoding, storage and retrieval? Encoding: getting memories in (often via STM but sometimes directly into LTM). Converting sensory input from the external world into a form that the brain can store. Storage: storing memories by consolidating them, memories become activated enough times for them to become permanently stored (in LTM). Retention of encoded information. Retrieval: getting memories out (of LTM). Each of these processes can be either conscious or unconscious. What factors affect encoding? 1. Level of processing (depth of processing). 2. Attention 3. Rehearsal or spaced repetition 4. Organisation & chunking or use of mnemonics 5. Modality (individual differences so whether you are a visual learner or an interactive learner, how you engage with material). 6. Unique or distinct elements might be better remembered. What factors affect retrieval? 1. How well the information was processed initially (depth and breadth). 2. Context and cues (the more similar the context or the better the cues, the easier it will be to remember something). 3. ‘Tip of the tongue phenomena’ (the more you think about something, the harder it gets to remember it even though you know it). 4. Amount of retrieval support (trigger words, MCQs). Recognition (identifying previously encountered information from a list of options) provides additional retrieval cues that aid memory. 5. Attention What is the relevance of memory in our lives? 1. Skills (learning how to drive, or how to walk) 2. Knowledge (store facts you can later refer to such as address) 3. Continuity and context/a narrative. (allows us to connect with the world around us) 4. Communication (recognising facial expressions). 5. Goal setting (how to make progress, future goals) 6. Arise from and contribute to a shared social world. (gives relationships their identity) 7. Sense of self. What is autobiographical memory? It is long-term memory for personal experiences and personal knowledge of one’s life, it can be specific or generic. It is a memory for our lives, with functions including social connection, identity, and future thinking. It is built from episodic elements, personal knowledge (semantic) and general knowledge (semantic); it is unevenly distributed across the lifespan. Our AM gives us a narrative and a sense of identity. It guides out decisions and provides the social glue for us to build and maintain relationships. It is constructive and each time we remember a fleeting moment from our brain, we piece these pieces together to create an episodic memory of an event. What are some key features of autobiographical memory? 1. Memories are records of people’s experiences of life, not a record of the event itself. 2. Remembering is a constructive and reconstructive process. 3. Memories for experienced events are always incomplete. 4. Memories typically contain only a few highly specific details. 5. People can remember events that they have not experienced – experiences can be malleable and flexible; we would not want our knowledge to be like this. 6. Current knowledge/state of mind/context will influence how we record and retrieve memories. What are the 3 functions of autobiographical memory? 1. Directive (guides and shapes behaviour, utilises past decisions for problem-solving or for predicting and planning the future). 2. Social (facilities social interaction by sharing and reminiscing, allows for the creation of new relationships whilst nurturing existing ones, strengthens parent-child bond). 3. Self (constrains what the self is, has been and can be; memories can be altered and fabricated to be coherent with self). The ability to recall past events help individuals to regulate their emotions by drawing on the emotional content associated with those memories. How can we study autobiographical memory? It is quite difficult to measure due to questionable accuracy however cue words are used for an AB memory test, clinically AB memory interviews are conducted. Diary studies are also done but these take a lot of commitment and are very time-consuming. What is Conway’s self-memory system? 1. Episodic elements: building blocks (sights, smells, thoughts, and feelings). 2. Simple episodic memories: built up from episodic elements. 3. Complex episodic memories: all memories are drawn together to create a framework and create a sense of self. Conway's model emphasizes the dynamic nature of autobiographical memory and highlights the continuous construction and reconstruction of the self through the interplay of episodic and semantic memories. It provides a framework for understanding how individuals organize and make sense of their personal experiences in the context of their self-concept. How does autobiographical memory change across one’s lifespan? There are generally very few memories from early childhood, but the number of memories increases in young adulthood followed by a decrease in mid-life (the reminiscence bump). There is an increase again in memories in later years of life (the recency effect). What is the nature of childhood memory? Implicit memory is consistent and robust throughout childhood, implicit memory is your ability to be influenced by something that might have happened to you without you having any conscious recollection of it. However, declarative memory (our ability to consciously recall something) changes as most of our early memories (less than 2 years old) are lost or not available for conscious recall, forgetting also occurs more rapidly in children. Young children are also less prone to false memories and their narrative recall contains fewer details and those details are more quickly forgotten. Conversations with adults is thought to increase the longevity of memories. What is the cognitive explanation for childhood amnesia? Episodic memories are dependent on semantic memories (knowledge of concepts) but this develops in tandem, the ability to bind memories into existing knowledge develops through childhood. All episodic detail tends to fade over time so long-term memories tend to be vague and decontextualised. The storage and integration of memories is dependent on the development of other cognitive components such as language and attention. What is the neurobiology of childhood memory? 1. As people get older, they are more likely to make false memories. Children do worse on a memory test but make fewer mistakes, they do not add words that were not there. This age-related increases in false memories are correlated with changes in the medial temporal lobe, parietal cortex, and the prefrontal cortex. 2. Adults and children were presented with congruent vs. non-congruent noun-colour pairs. Adults were more likely to be using their prefrontal cortex, parietal cortex and occipitotemporal lobe. Children were more likely to use their occipital lobe. Adults are more semantic whereas children were more perceptual. 3. As we age, structural and functional changes in the hippocampus and the prefrontal cortex correlate with better consolidation and strategic control of memory. How can stress impact early memory formation? Stress and trauma can have both enhancing and impairing effects. Extreme stress impairs but moderate stress strengthens. Systems mediating stress undergo key changes during childhood: HPA axis, amygdala, hippocampus. Prolonged early stress has negative effects on the hippocampus, amygdala and prefrontal cortex which leads to poorer consolidation of emotional information. It also inhibits neurogenesis which leads to poorer storage and retention of memories. What is the reminiscence bump? It refers to the increase in memories between 10 and 30 usually found in participants over 35. It may be more prominent for positive than for negative experiences and includes recall of things like films, books, and music. The reason we might remember more during this time is because our brains are at their peak and form stronger memories, you experience more first time/novel experiences during this time. Key moments in our lives happen, we form our identities and make very critical decisions. What are self-defining memories? Turning points that often appear in autobiographies, they contain significant knowledge on our progress towards certain goals and they are a reminder of one’s identity. Events are more likely to be remembered if they are personally important, unique, consequential, or emotional. What are flashbulb memories? They are vivid, detailed recollections of moments that might have been dramatic, surprising, or emotionally arousing. Interestingly, people mainly remember what they were doing in the moment rather than the event itself. Once formed, flashbulb memories are long-lasting and unchanged and described as peculiarly vivid. What is the difference between AB memories and FB memories? AB memories are reconstructed, dynamic and changeable whereas FB memories are fixed, highly durable, more detailed, and vivid. What is our memory like in old age? In old age, implicit memory stays very reliable and durable. But strategic recall gets worse gradually. We see loss in prefrontal cortex. What is forward telescoping? It's a type of memory distortion where individuals perceive past events as having happened more recently than they truly did. This can happen for various reasons, including cognitive biases, the fading of specific details over time, or the influence of other memories. LECTURE 9 – Models of Memory What does evidence from patients with brain lesions tell us? They suggest that memory can be damaged in different ways depending on the brain area that is affected. They show that classic amnesia results from damage to the hippocampus. Damage to the cerebellum seems to effect procedural memory. The evidence also indicates that memory involves a large number of brain structures and that there are independent facets of memory. How is EEG/ERP useful in studying memory? EEG – measures electrical activity of brain. ERP – represent the brain’s response to specific stimuli. It is useful for detecting precise timing (excellent temporal resolution) and the different components of memory. They contribute to our understanding of how memories are formed, stored, and retrieved. How is fMRI useful in studying memory? It is better for localisation (excellent spatial resolution) but less helpful for detecting timing. It measures changes in blood flow and oxygenation levels in the brain. For example, in a meta review by Binder, an fMRI showed that there are 7 regions involved in semantic memory so it can help differentiate between different memory systems. What are the key areas of the brain that are involved in memory? 1. Temporal lobes, specifically the hippocampus (important for episodic memory and the formation of new memories). 2. Prefrontal cortex (also important for episodic memory) 3. Amygdala (emotional components of remembering) 4. Diencephalon (thalamus and hypothalamus) 5. Cerebellum (procedural memory) 6. Basal forebrain (produces ACh, there are low levels of ACh in people with Alzheimer’s. How do we know that memory in non-unitary? 1. Stochastic independence: lack of correlation between 2 measures of memory at level of individual item. 2. Functional independence: finding experimental manipulations that effect performance on 2 measures of memory in different and even opposite ways. What is an explicit test? Involves the conscious, intentional recollection of information. It assesses a person’s ability to consciously retrieve and recall previously learned information. What is an implicit test? Refers to the non-conscious influence of prior experiences on current behaviour. It assesses the impact of past experiences on performance without requiring conscious awareness or intentional recollection. How can we separate areas of the brain associated with memory? We can visualise different areas of the brain and how they are related to memory by looking at brain injuries, brain scans or cognitive experimental psychology. Correlational studies have also demonstrated that performance on various measures of memory correlate with performance on specific neuropsychological tests. How is the non-unitary model of memory supported? 1. Animal work (one study looked at the difference between the striatum and the hippocampus and they found that when they lesioned the striatum all the reward leaning stops. Rats would not respond to the rewards as they normally would do but they are still able to run around the maze. If you lesioned the hippocampus, the rats cannot remember the route of the maze, but they respond to reward learning. 2. Neuropharmacology: scopolamine blocks ACh, it essentially blocks episodic remembering whereas haloperidol which is dopamine blocker will prevent reward- based learning but does not interfere with episodic memory. 3. Neuroimaging: left prefrontal cortex was important for semantic memory whereas right prefrontal cortex was important for episodic 4. Experimental psychology 5. Computational modelling What is prospective vs. retrospective memory? Prospective memory: involves remembering to perform a planned action at some point in the future. Future-oriented memory. Retrospective memory: involves the recall of past events, experiences, or information. Ability to retrieve information. Past-oriented memory. What is declarative vs. non-declarative memory? Declarative is conscious memory that is expressed through recollection, it is a way of modelling the world. It can be divided into semantic and episodic memory. Non-declarative is unconscious memory that involves experience modifying behaviour without actually requiring any conscious memory content of the experience. These two work in parallel to support behaviour. How is the memory system organised? Long-term memory can be divided into declarative memory and non-declarative memory. Declarative memory can be divided into episodic and semantic memory which both involve the hippocampus, the diencephalon, and the prefrontal cortex. Non-declarative memory can be divided into procedural memory (basal ganglia), priming (neocortex), simple classical conditioning (amygdala, cerebellum) and habituation & sensitisation (reflex pathways). What is the anatomy of the hippocampus in terms of memory? Hippocampus is part of the limbic system and receives input from the entorhinal cortex which itself receives input from the parahippocampal cortex. Hippocampus also has rich connections with the amygdala, the anterior temporal cortex, and the prefrontal cortex. Hippocampus is the site of long-term potentiation, and it is the hub of episodic memory. Explain the concept of place cells in the hippocampus particularly in rodents. Place cells are neurones in CA1 and CA3 that fire when a rodent occupies a specific location. They are crucial for spatial navigation and creating cognitive maps. Place fields are the area that trigger firing in a specific place cell. So, when rats go through a sequence and return back to receive a reward, they replay that entire behavioural sequence. They replay it in reverse at the end of the run and then forward replay it at the beginning. What does research say about the role of the hippocampus in memory? The hippocampus and related structures (parahippocampal system) undoubtedly play a vital role in the formation of memories. It is the site of plasticity. However, some people think that the role of the hippocampus is temporary (e.g., with temporal gradient of retrograde amnesia) but some believe that it is very important in retrieval. Some evidence also suggests that memories may be stored across the cerebral cortex. The prefrontal cortex plays a vital role in the executive aspect of memory, and it works alongside the hippocampus. What other areas of the brain are important? Damage to HM’s brain goes beyond the hippocampus, adjacent areas and also white matter tracts are also independently important. Other important sites are mammillary bodies (posterior part of hypothalamus), thalamic nuclei, retrosplenial cortex. What is the role of the prefrontal cortex in memory? It plays a key role in strategic control and the organisation of memories. Prefrontal lesions can cause impairments in free recall but strengthen cued recall, they can also cause a lack in insight and cause one to not use strategies however one can perform at near-normal levels when given structured encoding tasks or support at retrieval. What is the ventral lateral prefrontal cortex important for? Implementing selection process. What is the dorsal lateral prefrontal cortex important for? It is important for organisation. LECTURE 10 – Decision Making What is decision making? It can be defined as the cognitive processes that undermine the selection of one course of action from several alternatives. A decision made under risk has more information available and thus, one will know what the outcome is and the probability of occurrence. These kinds of decisions are made with logic. A decision made under uncertainty has less information available and thus, one will know what the outcome is but not the probability of occurrence. These kinds of decisions are made with rules of thumb/heuristics or intuition. What is irrationality? Irrationality means that we all have inherent biases in our decision making. We make smart bets based on unconscious rules and these unconscious rules are referred to as heuristics or rules of thumbs. Visual illusions provide a metaphor for irrationality. What is Kahneman’s dual process theory of decision-making? We have 2 modes of thinking that govern our decision making: system 1 and 2. System 1 is intuitive thinking. It is fast, effortless, unconscious, triggers emotions. It is our default mode of thinking. It is working memory independent; it is autonomous and independent of cognitive ability. Advantages of system 1: high speed of response in a crisis, easy completion of routine (autopilot) or repetitive tasks, creativity through associations so it is good for expansive thinking. Disadvantages of system 1: one jumps to conclusions, unhelpful emotional responses, can make errors that are not detected, poor judgements. It uses heuristics and rule of thumbs so cognitive biases can often arise. System 2 is logic and reason. It is slow, effortful, conscious, logical, deliberative and can handle abstract concepts. It is working memory dependent, requires mental stimulation, correlated with cognitive ability. Advantages of system 2: it allows reflection and consideration of the bigger picture, options, pros and cons, consequences. Can handle logic, maths, statistics. It is good for reflective thinking. Disadvantages of system 2: It is slow, so requires time. It requires effort and energy, which can lead to decision fatigue. What are heuristics? Heuristics: cognitive rules of thumb/mental shortcuts (heuristics), they simplify the decision- making processes to allow for quick and efficient decisions, occasionally send us off course. What are framing heuristics? The observation that people make different choices depending on how the information about the decision is presented. Examples include decoy effect, gains and losses, opting in and opting out. What is the decoy effect? It refers to the change in preferences between two options when a third option is presented. The third option (decoy option) has to be an unattractive option that makes one of the other choices seem more attractive. Even though no one really chooses the decoy option, it still biases people’s decision-making. What are gains and losses in framing heuristics? People are more reluctant to lose money and therefore will take greater risks to avoid this. A person is risk-seeking to avoid losses, but they are risk-aversive for gains. People tend to sell stocks too soon if they go up and keep them too long if they lose. We have an irrational tendency to be less willing to gamble with profits than with losses. What is opting in and opting out? Ticking a box to OPT-OUT of being an organ donor might mean a country will have more organ donors simply because people did not want to tick and they adopt the default option as it usually requires the least amount of effort. What are anchoring heuristics? When people base judgements on implicitly suggested reference points (anchors). Individuals rely too heavily on the first piece of information encountered (the anchor) when making a decision. What are availability heuristics? States that we judge the probability of an event by how quickly and easily examples come to mind and we make decisions based on knowledge that is readily available rather than examining all the possibilities. What does Gigerenzer say about heuristic research? Gigerenzer criticised much of the work on heuristic research claiming that it is too focused on errors and painting heuristics in a negative light. He highlighted that the work of Kahneman does not really reflect how we make decisions but only how we make certain kinds of decisions. He highlighted that heuristics capture naturalistic decision making. He proposed a concept of ecological rationality – this refers to the idea that heuristics are neither good or bad but instead well adapted or not well adapted to a given environment. What brain regions underly decision making? Striatum: processing gains, aids decision making by representing reward values. Dorsolateral prefrontal cortex: working memory, planning, reasoning. More responsible for system 2, more deliberate thinking. Allows forward-planning. Orbital frontal cortex: working memory for emotion. Amygdala: processing of losses and threats, detects fear. Alerts our neural system of negative aspects of feedback. What effect does stress have on decision-making? Stress can increase impulsivity which may be linked to the activation of the ‘fight or flight response’. Some individuals make become more risk-averse whilst others may become more risk-seeking. Stress has been associated with impairments in memory so people might not be able to recall information relevant to the decision. The ‘anchoring’ effect may also occur where individuals rely too heavily on the first piece of information encountered. LECTURE 11 – The Aging Brain What stereotypes exist for older people? The stereotypes are a mix of negative (less competent, unproductive, burden, asexual) and positive (more warm, friendly, wise, experienced, reliable), they elicit feelings of pity and may lead to patronizing and protective behaviour, they are pervasive across cultures and are present from the age of 6, they can lead to dehumanisation and may influence health outcomes. What are negative stereotypes of age linked with? They are linked with memory impairments, Alzheimer’s disease, slower recovery from disability, poor health behaviour and physical functioning and poor cardiovascular health. What are the effects of subjective age on health? 1. Depression 2. Diabetes and hypertension 3. Cognitive impairment and dementia 4. High vulnerability to stress 5. Poor sleep quality 6. Higher systemic inflammation & adiposity/poor pulmonary and muscular functions What are the effects of subjective age on mortality? Stephan et al., 2018 carried out 3 longitudinal studies with more than 17,000 people and found that people felt on average 15-16 years younger. Across all samples, risk of mortality was twice as high among those who felt older than their age compared to those who felt younger than their age. Feeling 8, 11 and 13 years older was associated with 18%, 29% and 25% higher risk of mortality. This is mediated by disease burden, physical inactivity, functional limitations, and cognitive problems but not depressive symptoms. This study was controlled for education, race, and marital status. What are some key anatomical changes of the aging brain? There is an overall decline in grey matter volume, pattern is not uniform, the parts that are particularly affected include: limbic system (learning, memory, and emotion), frontal lobes (planning, strategy and working memory), substantia nigra (movement, reward, and learning), locus coeruleus (stress, panic, and REM sleep), cerebellum (movement and balance) and the caudate (executive functions, reward system). What are some cognitive changes in the aging brain? There is usually some reduction in fluid intelligence (logical problem solving), processing speed (affects ability to do complex tasks or those with timed elements), executive functions (planning and disinhibition) and memory (especially recall, source memory, prospective memory and working memory. What is the normal age-related memory loss? There are very few changes in implicit memory, procedural memory and STM. With semantic memory, there are relatively few reductions but more tip of the tongue experiences. There is a gradual but reliable reduction in episodic memory, recall is more affected than recognition; recognition is more reliant on familiarity than recollection. There is a reduction in prospective memory and source/context memory. Which cognitive functions are not affected by age? Knowledge and wisdom continue to grow, crystallised intelligence remains stable (ability to apply knowledge and skills). Vocabulary continues to grow, and some aspects of memory are resilient like recognition memory. What are the two main theories to explain cognitive changes in old age? 1. General resource theory: decline in ability to do any task that can be explained solely by a decline in general ability such as processing speed or attention. 2. Neuropsychological theories: task performance depends on intactness of different parts of the brain or of connections, especially hippocampal structures, and prefrontal cortex. According to the reserve theory, individuals who engage in mentally stimulating tasks throughout life might develop a neural reserve. What is exogenous? Physiological changes. What is endogenous? Changes to the environment. What factors can protect and compensate cognitive functioning in old age? Factors that are shown to protect cognitive functioning are: physical activity, physical health (especially cardiovascular), mental health and stress management, diet, and social support. Factors that can compensate are cognitive strategies, hyperactivity in frontal cortex and increased bilateral function. What is the scaffolding theory of aging and cognition? It aims to explain how various cognitive functions change over the course of aging. As people age, they compensate for declines in certain cognitive abilities by relying on cognitive scaffolding which involves using support mechanisms and strategies to maintain overall cognitive performance. It involves older adults employing compensation mechanisms, using external support such as notes or technology, they may also adapt their problem-solving approaches to better align with their changing cognitive abilities. It highlights the adaptive and compensatory strategies that people can employ to maintain cognitive functioning. What is normal pressure hydrocephalus? An abnormal build-up of CSF in the brain’s ventricles, this causes the ventricles to enlarge and put pressure on the brain. It can lead to poor balance, trouble walking and forgetfulness. What is dementia? It is a syndrome (group of signs/symptoms characteristic of an illness) NOT a disease. It is the loss of intellectual (cognitive functioning) at sufficient severity to interfere with daily functioning. Symptoms may also include changes in personality, mood, and behaviour. It is progressive and often irreversible but in some cases it can be treatable. What are the early clinical features of dementia? Memory loss, problems with language, disorientation of time and place, difficult with familiar tasks, impaired judgement, personality changes, problems with abstract thinking, misplacement of familiar things, inexplicable changes to mood and behaviour, and loss of initiative. What is some cause of dementia? 1. Neuronal degeneration: cortical (Alzheimer’s disease), sub-cortical (Parkinson’s disease, Huntington’s disease). 2. Blood vessel injury (stroke): vascular dementia. 3. Neurotoxic reactions to alcohol or drugs: Korsakoff’s syndrome (memory disorder due to B1 deficiency and alcoholism. 4. Infection to nervous system: AIDS dementia complex, Creutzfeldt-Jakob disease. What is Parkinson’s disease? It is caused by the degeneration or destruction of dopamine-producing nerve cells. This neural degeneration disrupts the CNS’s capacity to control and coordinate muscle movement. The substantia nigra (where dopamine is produced, has effects on movement control) is the site of neural degeneration. What is Lewy body dementia? It is the most common form of dementia. Protein deposits called Lewy bodies develop in the nerve cells in the brain, these affect brain regions involved in thinking, memory, and movement. The biggest difference between LBD and PD is the order of onset of the symptoms. What is the prognosis in Alzheimer’s disease? It is a slow deterioration initially, cognitive symptoms become incapacitating. Average length of time from diagnosis to death is 4 to 8 years although it can take 20 years for the disease to run its course. What are some advanced features of Alzheimer’s disease? Speech becomes monosyllabic and disappears, fleeting psychotic symptoms, behavioural and emotional disturbance, loss of bladder and bowel control, mobility deteriorates. What is the prevalence of dementia? In 2001, there were more than 24 million dementia cases worldwide. By 2040, it is estimated that there will be 81 million cases worldwide; this increased rate is due to increased life expectancy. It affects less than 1% of people aged 60-64 years but it affects between 24% and 33% of people ages 85 years and older. What are some causes and risk factors for Alzheimer’s disease? There is a clearer link between Alzheimer’s and ageing, genetics, cerebrovascular disease, depression, and head injury. Some less established links are obesity/diabetes, smoking, cardiovascular disease, reduced physical and mental exercise, low educational/occupational attainment. What is some brain-based biological markers of Alzheimer’s disease? There is overall brain shrinkage especially of the cerebral cortex, hippocampus, and entorhinal cortex (neuronal loss), there is ventricular enlargement, presence of neurofibrillary tangles, presence of amyloid plaques (extracellular deposits). The temporal and frontal areas of the brain are most affected by these changes. Cortical atrophy in an Alzheimer’s patient’s brain is evident at post-mortem. What are neurofibrillary tangles in Alzheimer’s? They are intracellular. They are intraneuronal structures composed of a protein called Tau, they are highly phosphorylated and insoluble. They have a structure of a twisted, paired helical filament. The abnormal phosphorylation of Tau proteins causes the structural integrity of the affected neurone to become compromised so their normal functions are disrupted. What is beta-amyloid plaques in Alzheimer’s? They are extracellular. They are sometimes called ‘senile’ or ‘neuritic plaques’ and contain beta amyloid protein. They are abnormal deposits of protein fragments that accumulate between neurones and disrupt brain function. The presence of these structures is necessary for the diagnosis of Alzheimer’s as they appear to be toxic to brain cells. What is the link between Acetylcholine and Alzheimer’s? Cholinergic pathways of Alzheimer patients are damaged by build-up of amyloid plaques. This leads to a greatly reduced presence of ACh in the cerebral cortex. It is likely that cognitive impairment is related to cholinergic degeneration in the brain. What is the treatment for Alzheimer’s? There is no cure. Principle aim of drug therapy is to preserve cognitive function and delay the progression of the disease. Most drug treatments aim to inhibit acetylcholinesterase which is the enzyme that inactivates ACh at the synapse (Donepezil and Rivastigmine). Other newer drugs aim to reduce glutamatergic activity (Memantine). LECTURE 5 – Visual Processing What are the main stages of visual perceptual processing? Light enters the eyes and is focused by the cornea and lens onto the retina. Photoreceptor cells (rods and cones) in the retina convert light into electrical signals. These signals are transduced into neural impulses which are transmitted through the optic nerve to the brain. Information from the optic nerve is processed in the primary visual cortex. Several areas of the brain are utilised to detect features, for parallel processing, perceptual organisation, and depth perception. What is the contribution of visual illusions to psychological research? What are illusions, reality, and sensation? Illusions: misperceptions or distortions of sensory stimuli. Reality: the actual state of things, the objective, external world the exists independently of our perception. Sensation: the initial process of detecting and receiving sensory information through sensory organs. Does perception rely directly on information present in the stimulus? Perception is influenced by information from the stimulus, but it also involves a complex interplay between sensory information and various other cognitive processes. Expectations and context play a significant role in shaping perception (top-down processing). What are visual perceptions? They are unconscious inferences. It is a complex and dynamic process that involves our brain’s ability to receive and interpret the information that our eyes receive (the light in the visible spectrum reflected by the objects in the environment). What is perception? It involves innate mechanisms forged by evolution; no learning is required. It is necessary for survival, and it is direct in that there is enough information in our environment to make sense of the world in a direct way. The pattern of light reaching the eye (the optic array) provides unambiguous information about the layout of objects in space, this is direct with little to no processing involved. It arises through an interaction between sensory input (bottom/low level) and prior knowledge (up/high level). At least two areas of the brain are required for this interaction: the ‘site’ where analysis of afferent signal occurs and the ‘source’ which applies the relevant prior knowledge. What is bottom-up theory of perception? It is known as stimulus/data-driven processing because perception begins with the stimulus itself. Processing of incoming sensory input travels up from the sensory organs (eye/retina) to the brain in one direction from the retina to the visual cortex. Each successive stage in the visual pathway carries out more complex analysis of the input. No prior knowledge affects the interpretation. Lower-level processing which begins with the sense receptors (photoreceptors, rods, and cones). What is top-down processing? It is conceptually driven processing, it refers to the brain’s use of knowledge, beliefs, memory, expectations, and other cognitive factors to interpret sensory information. It denotes the use of contextual information in patter recognition. Higher-levels processing derived from perceptions and experiences. How does visual perception occur? It involves perceptual decision making that takes place in many areas of the brain. The brain must extract relevant information from the retina, encode the sensory information represented in the visual cortex and recruit high level processes (memory/expectations) to make a perceptual choice. The more complex the stimulus, the more complex the perceptual processing and the more areas of the brain involved. What are illusions? It is a mismatch between the objective and perceived properties of an object present in the environment. It is a common feature of visual perception, both in normal and pathological conditions. Illusions reveal that visual processing is not so straightforward. It is a valuable tool to explore normal perception and its impairments. Why do our visual perceptions differ? There are individual differences in health such as cortical idiosyncrasies. In disease, errors of perception (illusions) can be due to knowledge being misapplied; such insights may further our understanding of the mechanisms underlying psychotic symptoms such as hallucinations and visual distortions. What are ambiguous figures? They are pictures which change their appearance during prolonged viewing: a sudden and unavoidable mental switch occurs whenever two of more interpretations of a given picture are displayed. What is the bottom-up explanation for this ‘mental switch’ with ambiguous figures? Neural channels: sensitive to a particular form of stimulation in a particular region of the visual field. Visual adaptation: when neurones adapt to the one orientation/figure, they fatigue or weaken so neurones corresponding to the other orientation/figure are stronger causing the reversal in perception. Visual adaptation: important for survival, allows us to adapt to the environment. In the Necker cube test, sensory/low-level processing appears to occur for stimulus size. What is the top-down explanation for this ‘mental switch’ with ambiguous figures? Attentional or expectational factors become emphasised: Gregory argued that the object appears to flip between orientations because the brain develops two equally plausible hypotheses and is unable to decide between them. In the Necker cube test, relative high-level processing appears to occur for perceptual ambiguity. What is an example of a top-down visual processing effect? ‘The Hollow Face’: there is a strong visual bias of seeing a hollow mask as normal convex face. The bias of seeing faces as convex is so strong it counters competing monocular depth cues such as shading and shadows. What is the motion after-effect and what effect does it have on visual processing? It is the illusion of motion in a visual image caused by prior exposure to motion in the opposite direction. Neural adaptation occurs which is when prolonged viewing of motion in one direction desensitises the observer to motion in that direction so then a stationary stimulus appears to move in the opposite direction. Can you give an example of an illusion that is due to low level processing? Simultaneous contrast: perceived colour of one area is influenced by the colour of its surrounding context. LECTURE 4 – Brain Imaging What us a single cell recording? Before brain imaging tools, single cell recording was used where you insert a fine electrode into the brain tissue of animals, the animal was given a task and the changes in voltage were recorded. It was obviously very invasive and unethical. What are the problems with lesion studies (accidents or strokes)? The areas that are affected in each individual are different, the lesion can be big or small, it could be affecting the area of the brain next to it too. It is difficult to precisely identify the region that is required for a particular function. Single patient case studies might not be generalisable. What is the contribution of neuroimaging techniques to Psychology? Allow us to study both the structure and function of the brain, they allow us to ALSO study the structure and function of the animal brain and therefore make comparisons. It is non- invasive and totally safe. Why are there changes in blood supply when neurones are being fired. When we undergo a psychological process, part of our brain becomes active and causes neurones to fire which causes a change in the electrical supply. Because the neurones are very active, they use more oxygen and therefore more blood. How is MRI and EEG used in Psychology? They are neuroimaging or brain mapping tools that measure activity in the brain, collect data during an action or behaviour and provide correlations. MRI measures blood flow indirectly and EEG measures changes in electrical activity. How is TMS and TDCS used in Psychology? They are neurostimulation tools that change the activity in the brain, they collect data just after stimulation of the brain and they can infer casual relationships. How do participants visualise a stimulus in a functional MRI? They view images on a projector screen on a mirror system that is mounted on the head coil which is a part of the MRI scanner. What is an MRI? It is a non-invasive method to visualise anatomical structures. It produces and reconstructs 3D images based on the natural magnetic properties of certain atoms in the body. Unlike x- rays, MRI does not produce any radiation and can be repeated an infinite number of times. BUT you need to ensure that you do not have any metal in your body or in your pockets. Magnetic field strength is measured in Tesla (T), typical MRI scanner strength is 1.5T, 3T or 7T (the higher the Tesla strength, the more intense the MR signal). What is a structural MRI (sMRI)? A patient does nothing (they rest), and it produces a very detailed anatomical brain image with functional activation that occurs due to a cognitive process. What is a functional MRI (fMRI)? It involves doing a task to measure function. Brain activity is recorded usually from the beginning until the end of the experiment, they record the hemodynamic or electrical fluctuations that occur when neurones are active. They CANNOT demonstrate the casual role of a given region, only correlations can be made. It has great spatial resolution but lower temporal resolution (this is due to the delay in the hemodynamic response). How does a functional MRI (fMRI) work? It measures the contrast of blood that carries oxygen and blood that does not carry oxygen (BOLD response takes about 5 seconds but with EEG this happens straight away). This is an indirect measure of neuronal activity (it is indirect because we do not actually measure the firing of neurones but assume that firing neurones consume more oxygen). What is a key difference between sMRI and fMRI? The anatomical protocol (sMRI) has a much better signal to noise ratio and a higher spatial resolution. However, it takes 8 minutes to collect one anatomical MRI image whereas it only takes 2 seconds to collect an fMRI image. sMRI is used to visualise anatomical structures at a high resolution, fMRI captures changes in blood flow and oxygenation levels in response to neural activity. sMRI has high spatial resolution, fMRI has better temporal resolution. sMRI is used for structural brain mapping, identifying abnormalities or lesions, fMRI is used for functional brain mapping. What is an electroencephalogram (EEG)? It usually consists of at least 64 electrodes. It is the direct measure of neural activity using ERPs (event-related potentials) which are significant voltage fluctuations resulting from neural activity. It is better for temporal resolution as it measures electrical activity. EEG does not record the activity of single neurons, but rather detects the signals created when populations of neurons are active at the same time. They are not good at localising brain areas like fMRI but they are good in revealing the time-course (temporal aspect) of neural activity. What is the amygdala? It is a major component of neural circuitry of emotion, contributing to the detection and evaluation of emotionally salient stimuli as well as the expression of emotional responses such as fear. It is also active when we are learning new things. A larger amygdala is associated with mental disorders and difficulties in emotional responding, adults with an insecure attachment have a larger amygdala. What is the hippocampus? It exerts strong regulatory control over the hypothalamic pituitary adrenal (HPA) axis stress response system, ultimately serving to modulate cortisol output via the same hippocampal glucocorticoid receptors that are susceptible to early environmental experiences. Also, very important for memory. What are some studies using sMRI in Psychology? London taxi drivers have a greater hippocampus due to increased memory. People with major depressive disorder have smaller volumes of basal ganglia, thalamus, hippocampus, and frontal lobe. Adults with autism have reduced corpus callosum (social functioning) and children with autism have increased amygdala volume. What are some studies using fMRI in Psychology? People with prosopagnosia did not have activity in the fusiform area as they were not able to recognise faces. People with major depressive disorder had less activity in the nucleus accumbens. People with bipolar disorder had an activation in the nucleus accumbens when they were angry. What is transcranial magnetic stimulation (TMS)? It is non-invasive and painless. A strong magnetic field is used to cause electric current at a specific area of the brain through electromagnetic stimulation. You can make the brain area more active or less active. What is transcranial direct current stimulation (tDCS)? It is non-invasive and painless. It uses direct low electrical currents to stimulate specific parts of the brain. Anodal stimulation increases neural excitability whereas cathodal stimulation decreases it. tdCS can increase or decrease cortical excitability depending on electrode polarity and position. In a study using tDCS, decreasing visual cortex excitability led to increased visual imagery strength. What happened to Phineas Gage? In a premature explosion, a one-metre-long tamping iron drove through his head. Much of his prefrontal cortex was destroyed and his behaviour was altered, namely: his decision- making skills, emotion, social interaction, and personality. What happened with Henry Molaison? He had surgery to treat his epilepsy, both his left and right medial temporal lobes were resected including most of the hippocampi. He was left with severe amnesia, but his general intelligence and language seemed to be preserved but he could not form new autobiographical memories. What are the differences between neuroimaging tools and neurostimulation tools? Neuroimaging tools are used to visualise and study brain structure and function. An example is fMRI (excellent spatial resolution) and EEG (excellent temporal resolution). Neurostimulation tools are designed to modulate neural activity and investigate casual relationships. An example is TMS and tDCS. What are the differences between fMRI anf EEG? fMRI measures changes in blood flow and oxygenation levels, it indirectly detects brain activity by using BOLD contrast, EEG measures electrical activity of the brain directly by recording voltage fluctuations from activity of neurones. fMRI has poorer temporal resolution compared to EEG which can capture millisecond-level changes in neural activity. fMRI has better spatial resolution than EEG. fMRI can penetrate deep into the brain whereas EEG measures from the cortical surface. The circle of Willis is described as an anastomotic system. What does that mean? It means that the circle is formed by anastomoses that allow blood to flow between two distinct arterial systems: the internal carotid and vertebrobasilar systems. Name the two collateral pathways in the circle of Willis. The anterior and posterior communicating arteries. What evolutionary advantage do the collateral pathways provide? Organisms with these collateral pathways are more likely to survive occlusive disease of the internal carotid arteries. How many cerebral arteries are there? Three: anterior cerebral artery, middle cerebral artery and posterior cerebral artery. Most people have a complete circle of Willis. Do most people have well developed communications between all its parts? No. Less than 50% of the population have a circle of Willis with well-developed communications between all its parts. Why is it clinically important that most people do not have a complete circle of Willis? Asymmetry is a significant factor in the development of intracranial aneurysms and ischemic stroke. In cases of internal carotid occlusive disease (atherosclerosis), the presence of a non- functional anterior collateral pathway is strongly associated with ischemic stroke. How many cerebellar arteries are there? Three: superior cerebellar artery, anterior inferior cerebellar artery, and posterior inferior cerebellar artery. What is the average cerebral blood flow in humans? The average cerebral blood flow is approximately 55mL per 100g of brain tissue per minute (15% of cardiac output). What percentage of total oxygen consumption is used by the brain. Approximately 25%. What does CVA stand for? Cerebrovascular accident (such as a stoke). What does the acronym FAST stand for? Face, Arms, Speech, Time. The common visible symptoms of a CVA: Face (drop or paralysis on one side), Arms (paralysis or reduction in strength in one arm), Speech (slurred speech), Time (intervention is time-critical). What is the Circle of Willis? It is an anastomotic system of arteries. It sits at the base of the brain and encircles the stalk of the pituitary gland. It links the blood supply of the forebrain and hindbrain.

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