Biological Psychology Notes Week 3 PDF

Topic 3: Biological psychology Part 2 The Nervous System: An Overview Neurons are the building blocks! Consistently created and pruned during life Action potentials nerve impulse or electrical signals that travel down an axon Glial cells support, nourish & protect neurons Ne...

Topic 3: Biological psychology Part 2 The Nervous System: An Overview Neurons are the building blocks! Consistently created and pruned during life Action potentials nerve impulse or electrical signals that travel down an axon Glial cells support, nourish & protect neurons Neurons meet at synapses Neurons communicate through neurotransmission Neurons= queen bee Glial cells = worker bees Neurons: the brain’s communicators Neurons are nerve cells, specialized in communication with each other Building blocks of the nervous system Transmit information in the form of electrical signals  Neural components Cell body (soma): Dendrites: branchlike centre of neuron, builds extensions that receive new cell components information Axon terminal: knob at the end of the axon Axons: “tails” that containing synaptic transmit information vesicles filled with neurotransmitters Synapse (synaptic clef): space between neurons through which NTs travel (meeting place) Dendrites listen, axons speak! Glial cells Glial means glue Plentiful in the brain Play valuable support role, involved in psychological functioning (e.g., make myelin) Bodyguards: feed & protect Myelin sheath Fatty insulation from glial cells surrounding axon Multiple sclerosis (ms): loss of myelin causes erratic signals How does a neuron fire? Electrical impulse is called the action potential Step 1: resting potential Neuron is polarized (negative inside, positive outside) Selectively permeable – gates don’t allow sodium ions (Na+) to pass through  How does a neuron fire? Step 2: action potential – brief electrical charge that travels down neuron Transmits neural messages to other neurons, muscles etc. When stimulated, neuron depolarized (gates open, Na+ rushes in) All-or-none law Frequency = intensity How does a neuron fire? Step 3: repolarization Potassium (Ka+) flows out repolarizing the axon Step 4: return to resting potential Step 5: refractory period Brief period of time where neuron won’t fire no matter how much stimulation Electrochemical communication When an electrical signal reaches the end of an axon (electro), it triggers the release of neurotransmitters into the synapse (chemical) Neurotransmitters then bind to receptors of receiving neuron’s dendrites, transmitting the signal Excitatory: messages that make it more llikely a neuron will fire Inhibitory: messages that make it less likely that a neuron will fire Neurotransmitters Chemical messengers that help neurons communicate with each other Influence emotions & mood (serotonin & dopamine) Control movement (acetylcholine) Regulate sleep and alertness (GABA & norepinephrine) Learning & memory (glutamate) Implicated in mental illness Neurotransmission Release Reuptake Action potential triggers Excess NTs are removed by neurotransmitter (NT) released drifting away, being broken down, from vesicles into the synaptic or reabsorbed. cleft. Reuptake: NTs are taken back NTs bind to receptors on the into the presynaptic neuron postsynaptic neuron (lock and (recycling!) key). Some drugs (e.g., cocaine) block reuptake, prolonging NT effects. Neurotransmitters: helpers & blockers Agonist: mimic or enhance the effect of an neurotransmitter (helpers) Antagonist: block or impedes the normal activity of a neurotransmitter (blockers) Opioids (e.g., fentanyl) vs. Naloxone Schizophrenia associated with excess dopamine —> dopamine antagonists prescribed (antipsychotic medication) Parkinson’s associated with low dopamine —> prescribed dopamine agonist Neurotransmitters Glutamate GABA Acetylcholine Dopamine Serotonin Anandamines  Glutamate and GABA Most common NTs in the CNS Associated with learning and memory Glutamate is excitatory and increases the chance neurons will communicate Toxic in high doses, may contribute to schizophrenia and other mental disorders GABA is inhibitory, dampening neural activity Acetylcholine Arousal, selective attention, memory, sleep Anticholinergic: Benadryl, unison Increased risk of dementia Alzheimer’s —> neurons containing acetylcholine are destroyed, leads to memory loss Aricept -> boosts acetylcholine levels Insecticide limits breakdown (more acetylcholine) Dopamine Pleasure and reward, voluntary movement Attention Parkinson’s à deficit of dopamine Schizophrenia + symptoms à excess dopamine  Serotonin Sleeping, eating, mood, pain, depression Increase serotonin by: eating foods rich in tryptophan, working out, “runner’s high”, light exposure Depression drugs act on serotonin – increase availability MDMA causes massive release, empties tank  Selective serotonin reuptake inhibitor (SSRI) Used to treat depression Blocks reuptake of serotonin Zoloft, Prozac, Lexapro etc. Agonist or antagonist? The brain Major parts of the brain Neural Plasticity The brain you’re born with is not the brain The brain is adaptable and can change you’ll die with Myelination: makes neurons faster, brain regions more efficient Pruning: reorganizing to make bain more efficient! Remove some synaptic connections (e.g., pruning an apple tree) Plasticity decreases in adulthood  Neural plasticity in action London taxi drivers show larger hippocampus Acquired savant syndrome  Intergenerational trauma 1st observed in children of Holocaust survivors – also Vietnam veterans in US, residential school survivors in Canada Assumed that trauma was passed down through env’t or behavioural PTSD associated with changes in brain structure, function & chemistry which may be passed down – makes brain more vulnerable to trauma  Major regions of the brain  Hindbrain Reptilian/primitive brain Controls basic functions like eating, sleeping Major components: Medulla: vital functions like controlling heartbeat, muscles involved with breathing, vomiting, blood pressure, swallowing, etc. Pons: sleep & arousal Cerebellum: motor coordination (e.g., timing of leg and arm movements) Reticular Activating System: key in arousal (regulating sleep & wakefulness), directing attention, - dysregulated in ADHD brains Midbrain & forebrain Midbrain: controls movement and transmits information that enables seeing and hearing (relays information between the brain and the eyes and ears) Forebrain: manages complex cognitive activities, sensory and associative functions, and voluntary motor activities Major components: cerebral cortex, thalamus, hypothalamus, limbic system  Outermost layer of the brain, “grey matter” Cerebral cortex Higher mental processes (sense, self, reasoning) Consists of two cerebral hemispheres (4 lobes) connected by the corpus callosum Contralateral control Cerebral cortex: Lobes Lobes: Frontal: planning, decision making Parietal: sensation (somatosensory) Temporal: auditory Occipital: vision Lateralization Cognitive function that relies more on one side of the brain than the other Left hemisphere Right hemisphere Fine-tuned language skills Coarse language skills - Speech comprehension, production, - Simple speech reading, writing, etc. - Simple writing - Tone of voice Actions Visuospatial skills - Making Facial expressions - Perceptual grouping - Motion detection - Face perception Split brain surgery Procedure that involves severing the corpus callosum to reduce the spread of epileptic seizures  Frontal Lobes Planning, executive functions, motor Most sophisticated information processing Broca’s area: language production Motor cortex: responsible for body movement Prefrontal cortex: thinking, planning and language, the “CEO” Broca’s aphasia Phineas Gage: PFC damage Railroad foreman in 1848 in Vermont Tamping iron exploded and thrust into his head Destroyed most of his left prefrontal cortex Remarkable behavioural change following injury The psychopathy connection PFC important for thoughtful decisions, controlling impulses, regulating emotions Brain injuries involving PFC resulted in “pseudopsychopathy” People with psychopathic traits sometimes have abnormalities or reduced activity in PFC PFC damage linked to changes in moral judgment, deficits in guilt, empathy, learning from punishment Parietal Lobe Somatosensory cortex: sensitive to pressure, pain and temperature Communicates info to the motor cortex every time we reach, grasp, or move our eyes Temporal lobe Hearing, understanding language, storing autobiographical memories Contains the auditory cortex and Wernicke’s area, responsible for language comprehension Wernicke’s aphasia Occipital lobe Specialized for vision processing and higher-order visual functions (e.g., recognizing complex shapes) Located at the back of the brain “Seeing stars”? Activated your visual cortex! Damage can lead to prosopagnosia (face blindness), visual agnosia  Limbic system Emotional center – also a role in smell, motivation, and memory Hypothalamus: regulates and controls internal bodily states (homeostasis); controls pituitary gland Body temp, hunger & thirst, sexual behaviour etc. Thalamus: relays information from the sense organs to primary sensory cortex Limbic system Amygdala: plays key role in fear, aggression, excitement and arousal - Damage makes it impossible to recognize facial expressions for Toxoplasma threat/distress Hippocampus: spatial memory, damage causes inability to form new memories (anterograde amnesia) - Memories not stored here Pardini et al., 2015 Reduced amygdala volume implicated in development of severe & persistent aggression & the development of psychopathic personality Sample: 56 men with varying histories of violence Method: neuroimaging study Found that men with lower amygdala volume exhibited higher levels of aggression & psychopathic features from childhood to adulthood Lower amygdala volume also associated with aggression, violence, psychopathy traits at 3-year follow-up What would you guess are the top 10 sports/recreational activities that produce concussions?  Overview Nervous system: primary Endocrine system: communication system of the second communication body (fast, electrochemical system (slower, secretes communication) hormones into CNS à brain and spinal cord bloodstream) PNS à sensory and motor neurons connecting the CNS to the rest of the body Peripheral Nervous System (1) somatic nervous system conveys info from CNS to muscles (2) autonomic nervous system controls all the involuntary movements of the body (e.g., heart, breathing, and other organs), which is subdivided into: Sympathetic Nervous System Parasympathetic Nervous System Autonomic nervous system Sympathetic: fight or flight Parasympathetic: rest & digest When one is active, the other is inactive The polygraph Uses physiological measurements linked to ANS (e.g., galvanic skin response, heart rate, breathing) to “detect deception” How could you fool a polygraph? Endocrine system Series of glands that produce hormones to regulate normal bodily functions, regulate emotions The hypothalamus links the nervous system and endocrine system via the pituitary gland Pineal gland secretes melotonin – can calcify with age or Alzheimers MAJOR GLANDS OF THE ENDOCRINE SYSTEM Pituitary gland Controlled by the hypothalamus In turn, controls the other glands in the body Releases hormones that influence growth, blood pressure, and other functions Oxytocin Responsible for numerous reproductive functions, implicated in maternal and romantic love May be key in trust Oxytocin: the love hormone Child-mother attachment Mothers with higher levels of oxytocin across pregnancy & postpartum reported more behaviours that support attachment, committed to infant safety (Feldman et al., 2007) Ps given synthetic oxytocin gave more money to a stranger than control group (bond required for giving behaviour?) (Zak, 2007) “Oxytocin is a social glue… makes us care about other people” Endocrine disruptors