Untitled Quiz

PYB102 - The Mind and the Brain

• Course name: PYB102 - The Mind and the Brain
• Student: Anne Vas
• Exam date: November 14th, 2024

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

• Axon: Transmits signals away from the neuron's cell body to communicate with other neurons or muscles.
• Tracts vs. Nerves:
  • Tracts (CNS): Bundles of axons transmitting signals within the CNS.
  • Nerves (PNS): Bundles of axons transmitting signals outside the CNS.
• Nuclei vs. Ganglia:
  • Nuclei (CNS): Clusters of neuron cell bodies associated with specific functions (e.g., processing sensory or motor information).
  • Ganglia (PNS): Similar clusters in the PNS, typically involved in sensory or autonomic functions.

Central Nervous System (CNS) Neuroanatomical Directions

• Ventral: Towards the belly.
• Dorsal: Away from the belly (towards the back).
• Anterior (Rostral): Towards the front (nose).
• Posterior (Caudal): Towards the back of the head (tail).
• Medial: Towards the spine or midline.
• Lateral: Away from the midline.

Neuroanatomical Planes of View

• Sagittal (Medial): Cuts the brain into left and right sides.
• Coronal: Cuts the brain into front (anterior) and back (posterior) sections.
• Horizontal: Cuts the brain into top and bottom sections.

Divisions of the Brain

• Forebrain:
  • Telencephalon:
    • Cerebral Cortex: Involved in higher-level functions like thought, reasoning, sensation, and voluntary muscle movement.
    • Limbic System: Involved in emotion, memory formation and motivation. Includes Amygdala (processes emotions and fear responses) and Hippocampus (critical for memory formation and spatial navigation).
    • Basal Ganglia: Plays a major role in movement control and planning.
  • Diencephalon:
    • Thalamus: Relay station for sensory information (except smell), filtering and organizing inputs.
    • Hypothalamus: Regulates basic drives (e.g., hunger, thirst, sex) and controls autonomic nervous system, influencing functions like body temperature and fight-or-flight responses.
• Midbrain
  • Superior Colliculi: Relay and process visual information.
  • Inferior Colliculi: Relay and process auditory information.
• Hindbrain:
  • Medulla: Controls essential autonomic functions (e.g., heart rate, blood pressure, respiration).
  • Pons: Acts as a bridge between different brain regions, regulating consciousness and alertness.
  • Cerebellum: Coordinates voluntary movements, balance, and posture.

Brain Development

• Divisions originate in the earliest stages.
• Neural tube grows to form the central nervous system.
• Developing neural tube forms discrete enlargements or vesicles.
• Embryonic vesicles develop into major brain regions (forebrain, midbrain, hindbrain).

Lobes of the Cerebral Cortex

• Occipital Lobe: Primarily responsible for vision.
• Parietal Lobe: Processes sensory information (touch, pressure, temperature, pain).
• Temporal Lobe: Processes auditory information, memory formation, and language.
• Frontal Lobe: Involved in complex processes like reasoning, planning, movement, speech, and problem-solving.

Lateralisation and Contralateral Arrangement

• Left cerebral hemisphere is lateralised for language.

• Left hemisphere processes somatosensory stimuli from the right side

• Visual stimuli from the left visual field is projected to the right hemisphere.

• Right hemisphere processes somatosensory stimuli from the left side.

• Visual stimuli from the right visual field is projected to the left hemisphere.

Split-Brain Experiments

• Used to investigate the lateralisation of the cerebral hemispheres.
• Patients with severe epilepsy had their corpus callosum severed.
• Left hemisphere is more specialised for language.

Brain Support Systems

• Meninges: Protective sheaths around the brain and spinal cord (dura mater, arachnoid membrane, pia mater).
• Cerebrospinal Fluid (CSF): Shock absorber, protects the brain.
• Blood Supply: Blood-brain barrier; protects the brain.

Peripheral Nervous System (PNS)

• Spinal Nerves: Fusion of dorsal and ventral roots, carry sensory and motor information.
• Cranial Nerves: 12 nerves attached to the ventral surface of the brain, control many senses in the head and neck region.
• Autonomic Nervous System: Serves basic life functions (heart beating, response to stress, regulation of smooth muscle, regulation of cardiac muscle and glands).
  • Sympathetic system: Expenditure of energy from body reserves.
  • Parasympathetic system: Increases the body's supply of stored energy.

Neurons

• Basic Units: Communicate with each other via synapses (synaptic cleft).
• Functions: Reception, Conduction, Transmission
• Types of Glial Cells: Oligodendrocytes (cover axons with myelin).
• Parts of the neuron: Dendrites, Soma, Axon, Terminal buttons, Myelin

Cell Membrane and Action Potential

• Cell Membrane: Composed of a lipid bilayer with proteins controlling materials into and out of the cell.
• Action Potential: Brief reversal in resting charge of the neuron, triggered by the exchange of ions triggered when depolarization reaches a threshold.

Synaptic Transmission

• Neurotransmitters are stored in vesicles in terminal buttons,
• Action potentials trigger neurotransmitter release.
• Neurotransmitters diffuse across the synaptic cleft.
• Attach to receptor molecules, generating an action potential (Excitatory or Inhibitory).
• Neurotransmission terminated by reuptake, enzyme deactivation, or autoreception

Types of Postsynaptic Potentials

• EPSPs (Excitatory): Make the neuron more positive (depolarization)—increase likelihood of firing.
• IPSPs (Inhibitory): Make the neuron more negative (hyperpolarization)—decrease likelihood of firing.

Basic Processes of Memory

• Encoding: Transforming sensory stimuli into a form that can be placed in memory.
  • Key Component: Attention: Acts as a filer, allowing one stimulus to pass.

Storage

• Sensory Register: Registers and briefly holds information from the senses.
  • Types:
    • Iconic Memory: Visual system, duration < 1.5 seconds, Capacity 9-10 items
    • Echoic Memory: Auditory system, duration ~2 seconds, Capacity ~5 items.
• Short-Term Memory (STM): Intermediate storage (chunking, rehearsal). Duration can exceed 20 seconds with rehearsal, loses information via decay/interference.
• Working Memory: Temporary storage and manipulation of information, involves multiple components like phonological loop.

Retrieval

• Types:
  • Free Recall: Recalling items in any order (primacy/recency effects, context, internal state).
• Memory Memory by Duration: Iconic, short-term, and long-term memories.

Memory by Type

• Declarative Memory: Explicitly stated knowledge, like semantic or episodic memory.
• Nondeclarative Memory: Implicit memory, knowledge from doing, including: - Skills: riding a bicycle - Priming: increased likelihood of using a word. - Conditioning: reaction to a stimulus

Brain Structures Involved in Memory

• Case Studies: Henry Molaison (HM): Patient with hippocampus removed— severe anterograde amnesia
• Hippocampus: Essential for forming new memories.
• Formal Assessments of HM's Amnesia: Digit Span + 1 test; failure to form new long-term verbal memories.

Synaptic Mechanisms of Learning and Memory

• Long-Term Potentiation (LTP): Strengthening of synapses with repeated activity. Essential for forming long-term memories.

Consciousness and REM Sleep

• EEG: Measures electrical activity of brain waves.
• Types of Brain Waves: Beta (alertness), Alpha (relaxed), Theta (light sleep), Delta (deep sleep), and K-Complexes (wakefulness, NREM).
• EOG: Measures eye movements, detecting REM sleep.
• EMG: Measures muscle activity, detects muscle atonia (paralysis) in REM sleep.

Sleep Disorders

• Insomnia: Difficulty falling or staying asleep.
• Sleep Apnea: Breathing interruptions during sleep.
• Somnambulism (Sleepwalking): Engaging in activities while asleep.
• Night Terrors: Intense fear episodes during sleep.
• REM Sleep Behavior Disorder (RBD): Acting out dreams during REM sleep.
• Narcolepsy: Excessive daytime sleepiness and sudden sleep attacks.

Brain Regions Involved in Sleep Regulation

• Suprachiasmatic Nucleus (SCN): Master clock for circadian rhythms.
• Retina & Optic Nerve: Detect light signals to SCN; influences wakefulness and sleepiness.
• Hypothalamus: Controls various functions including sleep, hunger and body temperature,
• Pineal Gland: Produces melatonin, induced by light exposure.
• Pons: Crucial for regulating REM sleep; Inhibits motor neurons during REM to prevent acting out dreams.
• Thalamus: sensory relay station; involved in transitions between wakefulness and sleep.
• Lateral Geniculate Nucleus (LGN): Relays visual information to the visual cortex.

Emotion and Stress

• Basic Emotion Approach: Suggests a definitive number of emotions (surprise, anger, fear, sadness, disgust, happiness).
• Emotional vs Mood: Emotions are short-term, intense responses, whereas Mood is a longer-term state.
• Theories of Emotion:
  • James-Lange Theory: Emotion is a result of physiological responses.
  • Cannon's Criticism: Physiological responses are slow.
  • Schachter-Singer Two-Factor Theory: Physiological arousal is interpreted within a particular context to lead to emotions.
• Facial Feedback Hypothesis: Facial expressions influence emotional experience.

Brain Regions Involved in Emotional Processes

• Limbic System (Emotional Processing)
• Frontal Lobes (Expression of Emotions).
• Interaction among various brain regions for emotional experience.

Stress

• Stress: A challenge to a person's capacity to cope with demands.
• Physiological and Emotional Arousal: Lead to physical and emotional changes.

Autonomic Nervous System (ANS):

• Sympathetic Division: Activated during "fight or flight"
• Parasympathetic Division: Supports energy conservation and restoration.
• Hypothalamus: Activates stress response pathways.

Neural vs. Endocrine Communication

• Neural Communication: Fast, directed communication using neurotransmitters.
• Endocrine Communication: Slower, widespread communication using hormones.
• The HPA Axis: The Hypothalamic pituitary adrenal axis is responsible for regulating stress response throughout the body using endocrine and neural systems simultaneously.

Language and Aphasia

• Aphasia: Language disorders; from Greek "a-phato", meaning not speakable.
• Phonemes: Smallest units of sound in language.
• Morphemes: Smallest units of meaning in language.
• Semantics: the study of meaning in language.
• Syntax/Grammar: The set of rules that govern how we put words together.
• Dysgraphia: Inability to write effectively.
• Alexia: Inability to read effectively.
• Aphasia: Language disorder, resulting from damage to the brain language centers.
• Signs of aphasia:
• Paraphasia
• Neologism
• Non-fluent speech
• Types of Aphasia: Broca's Aphasia (difficulty producing speech), Wernickeʼs Aphasia (difficulty comprehending speech or producing meaningful language).

Acquired Brain Injury (ABI)

• Definition: Injury to the brain after birth resulting in cognitive, physical, or behavioral deterioration
• Causes: Traumatic brain injury resulting from accidents, falls, assaults; other causes include conditions such as strokes, poisoning, infections, drug/alcohol abuse, progressive conditions (Alzheimer's, Parkinson's).
• Consequences Physical, emotional, and cognitive impairments.
• Assessment of Damage: GCS (Glasgow Coma Scale), LOC (loss of consciousness), PTA (post-traumatic amnesia).

Strokes

• Ischemic Stroke: Blood clot blocks blood flow to the brain. (Cause: thrombus / embolus).
• Hemorrhagic Stroke: Rupture of an artery in the brain. (Cause: aneurysms / other conditions); causes blood leakage and damages brain cells.

High-Order Cognition: Executive Functions

• Executive functions: Cognitive processes allowing individuals to override, switch, and maintain goals, working memory.
• Cold Executive: Dealing with logical tasks.
• Hot Executive Functions: Involved with emotional tasks.
• Frontal Lobes: Key regions for executive functions, including Dorsolateral PFC ("executive circuit"), Orbitofrontal Cortex, and Mediofrontal Cortex.