Unit 3 Psychology – Brain Function Master Set

Nervous System

The body’s electrochemical communication network consisting of the CNS and PNS.

Central Nervous System (CNS)

Brain and spinal cord; processes, interprets, and sends commands.

Peripheral Nervous System (PNS)

All nerves outside CNS; sends info to and from CNS.

Somatic Nervous System (SNS)

Controls voluntary skeletal muscle movement.

Autonomic Nervous System (ANS)

Controls involuntary actions of internal organs and glands.

Sympathetic Nervous System

Activates “fight or flight” response; increases heart rate, respiration, dilates pupils.

Parasympathetic Nervous System

“Rest and digest”; conserves energy, slows heart rate, aids digestion.

Homeostasis

The body’s process of maintaining internal stability through balance of sympathetic and parasympathetic activity.

Neuron

A cell that transmits electrical impulses to communicate information.

Dendrites

Branch-like structures that receive messages from other neurons.

Axon

Long fibre that transmits electrical impulses away from the soma.

Myelin Sheath

Fatty insulation that speeds up neural transmission.

Axon Terminals

Branches that release neurotransmitters into the synapse.

Synapse

Junction between two neurons where neurotransmitters are exchanged.

Sensory (Afferent) Neuron

Transmits sensory input from body to CNS.

Motor (Efferent) Neuron

Sends commands from CNS to muscles/glands.

Interneuron

Connects sensory and motor neurons within CNS for processing.

Action Potential

The electrical impulse that travels along an axon when a neuron fires.

Neurotransmission

The process of sending a signal across a synapse using neurotransmitters.

Reflex

Automatic, unlearned response to a stimulus enhancing survival.

Reflex Arc

Neural pathway controlling a reflex action (receptor → sensory neuron → interneuron → motor neuron → effector).

Monosynaptic Reflex

Involves one synapse (e.g. knee-jerk).

Polysynaptic Reflex

Involves interneurons and multiple synapses (e.g. withdrawal reflex).

Spinal Cord

Relays information between brain and body; controls reflexes independently of the brain.

Forebrain

Responsible for cognition, memory, emotion, language.

Midbrain

Coordinates movement, arousal, sleep.

Hindbrain

Regulates vital functions and balance.

Cerebrum

Largest brain area; divided into two hemispheres linked by the corpus callosum.

Corpus Callosum

Thick nerve fibres connecting left and right hemispheres.

Cerebral Cortex

Outer 3mm layer of cerebrum; involved in complex thought, perception, planning.

Gyri and Sulci

Folds and grooves that increase surface area for neural connections.

Localisation of Function

Specific areas perform specific functions.

Distributed Function

Multiple brain regions share functional responsibility.

Frontal Lobe

Motor control, planning, reasoning, personality, emotion regulation, speech (Broca’s area).

Parietal Lobe

Sensory processing (touch, temperature, pressure, pain) and spatial awareness.

Temporal Lobe

Auditory processing, language comprehension (Wernicke’s area), memory.

Occipital Lobe

Vision; houses the primary visual cortex.

Primary Motor Cortex

Controls voluntary skeletal movement.

Primary Somatosensory Cortex

Processes bodily sensations.

Primary Auditory Cortex

Interprets sound information.

Primary Visual Cortex

Processes visual input (shape, colour, motion).

Association Areas

Regions integrating info for higher-order thinking and decision-making.

Explicit Memory

Conscious recall of facts and events (e.g. names, dates).

Implicit Memory

Unconscious memory for skills and habits (e.g. riding a bike).

Hippocampus

Forms new explicit memories; encodes context of experiences.

Amygdala

Attaches emotion to memories, especially fear.

Neocortex

Stores long-term semantic (factual) memories.

Cerebellum

Forms procedural (skill-based) memories and coordinates motor activity.

Basal Ganglia

Involved in habit formation and smooth sequencing of movements.

Broca’s Area

Produces speech and coordinates muscles used for talking (left frontal lobe).

Wernicke’s Area

Comprehends spoken and written language (left temporal lobe).

Geschwind’s Territory (Angular Gyrus)

Connects Broca’s and Wernicke’s areas; integrates sound, sight, and meaning of words.

Broca’s Aphasia

Non-fluent, effortful speech; comprehension intact.

Wernicke’s Aphasia

Fluent but meaningless speech; comprehension impaired.

Arcuate Fasciculus

Nerve fibre bundle linking Broca’s and Wernicke’s areas.

Lateralisation

Specialisation of functions in one cerebral hemisphere (e.g. language → left hemisphere).

Voluntary Movement

Controlled action involving conscious intent.

Primary Motor Cortex

Initiates voluntary muscle movement.

Basal Ganglia

Selects and refines movements, suppresses unwanted ones.

Cerebellum

Coordinates timing, balance, and precision of movements.

Motor Pathway Sequence

Parietal lobe (position sense) → Frontal lobe (planning) → Cerebellum (refinement) → Primary Motor Cortex (execution).

Limbic System

Emotional and motivational brain network (amygdala, hippocampus, hypothalamus).

Amygdala

Processes emotions, especially fear and aggression.

Hippocampus

Links memories to emotional significance.

Hypothalamus

Maintains homeostasis; activates stress response (HPA axis).

Prefrontal Cortex

Regulates emotion, decision-making, impulse control.

HPA Axis

Hypothalamic-Pituitary-Adrenal system; releases stress hormones like cortisol.

LeDoux’s Short Route

Thalamus → Amygdala → fast emotional response.

LeDoux’s Long Route

Thalamus → Cortex → Hippocampus → Amygdala → slower, more accurate emotional processing.

Neurotransmitter

Chemical messenger that transmits signals across synapses.

Excitatory Neurotransmitter

Increases likelihood of neuron firing (e.g. Glutamate).

Inhibitory Neurotransmitter

Decreases likelihood of neuron firing (e.g. GABA).

Glutamate (Glu)

Main excitatory transmitter; involved in learning and memory.

GABA (Gamma-Amino Butyric Acid)

Main inhibitory transmitter; calms brain, reduces anxiety.

Acetylcholine (ACh)

Controls muscle contraction, attention, learning, memory.

Dopamine (DA)

Involved in movement, reward, motivation; imbalance → Parkinson’s or schizophrenia.

Serotonin (5-HT)

Mood regulation, sleep, appetite; low levels → depression.

Epinephrine (Adrenaline)

Triggers fight-or-flight physiological response.

Norepinephrine (Noradrenaline)

Increases alertness and arousal; linked to stress and anxiety.

Synaptic Transmission

Process of electrical impulse causing release of neurotransmitters that bind to receptors on next neuron.

Neurotransmitter Malfunction

Imbalance in neurotransmitter levels or receptor function.

Parkinson’s Disease

Low dopamine in basal ganglia (substantia nigra degeneration); tremors, rigidity, slow movement.

Alzheimer’s Disease

Low acetylcholine; progressive memory loss and cognitive decline.

Schizophrenia

Excess dopamine activity; disorganised thoughts, hallucinations.

Depression

Low serotonin and norepinephrine; persistent sadness, lack of motivation.

Anxiety Disorders

Low GABA, high norepinephrine; hyperarousal and tension.

Neural Plasticity

Brain’s ability to reorganise itself by forming new neural connections.

Synaptic Pruning

Elimination of weaker synaptic connections during development.

Myelination

Growth of myelin sheath to increase transmission speed and efficiency.

EEG (Electroencephalogram)

Measures electrical activity in the brain via scalp electrodes.

fMRI (Functional Magnetic Resonance Imaging)

Detects changes in blood flow to show brain activity.

PET Scan (Positron Emission Tomography)

Uses radioactive tracer to measure metabolic activity.

Left Hemisphere Specialisation

Language, logic, analytical processing.

Right Hemisphere Specialisation

Spatial ability, creativity, facial recognition, emotion processing.

Corpus Callosotomy

Surgical separation of hemispheres (used to treat epilepsy).

Plasticity After Damage

Ability of undamaged brain areas to take over lost functions (especially in young brains).