Psychology Unit 1: Biological Bases of Behaviour

Vocabulary flashcards covering the biological bases of behaviour, including genetics, neural transmission, neurotransmitters, hormones, psychoactive drugs, brain anatomy, consciousness, sleep stages, and sleep disorders.

Heredity

Genetic traits and tendencies passed from biological parents to offspring.

Environment

Non-genetic influences, including upbringing, culture, experiences, and surroundings.

Nature vs. nurture

The question of how inherited genes and environment interact to shape behaviour.

Epigenetics

The study of how environmental and other factors change gene expression without changing DNA sequence.

Natural selection

Inherited traits that improve survival and reproduction tend to become more common over generations.

Evolutionary psychology

Uses evolutionary principles to study behaviour and mental processes.

Eugenics

Discredited efforts to control human reproduction to supposedly improve a population; associated with coercion and discrimination.

Central nervous system (CNS)

Brain and spinal cord; processes information and coordinates responses.

Peripheral nervous system (PNS)

Nerves outside the CNS that carry information to and from it.

Glial cells

Cells that support, nourish, protect, and sometimes insulate neurons.

Sensory / afferent neurons

Carry information from sensory receptors toward the CNS (afferent = arrives).

Motor / efferent neurons

Carry commands from the CNS to muscles or glands (efferent = exits).

Interneurons

Neurons within the CNS that process and relay information among neurons.

Somatic nervous system

Controls voluntary skeletal muscle movement and carries associated sensory information.

Autonomic nervous system

Controls largely involuntary functions involving glands and internal organs.

Sympathetic nervous system

Mobilizes the body for stress: fight-or-flight; increases heart rate and alertness.

Parasympathetic nervous system

Calms the body: rest-and-digest; slows heart rate and supports digestion.

Dendrites

Branching neuron structures that receive incoming signals.

Axon hillock

Region near the soma where input is integrated and an action potential is initiated if threshold is reached.

Axon

Long fiber carrying an electrical signal away from the cell body.

Myelin sheath

Fatty insulation around an axon that speeds conduction of neural impulses.

Nodes of Ranvier

Gaps in myelin where impulses are regenerated as they travel along the axon.

Synaptic vesicles

Small sacs in axon terminals that store neurotransmitters for release.

Synapse / synaptic gap

Junction, including a tiny gap, where one neuron sends a signal to another cell.

Action potential

Brief electrical impulse traveling along the axon after a neuron reaches threshold.

Threshold

Minimum depolarization needed to trigger an action potential.

All-or-nothing principle

A neuron fires a full action potential once threshold is met, not a partial one.

Refractory period

Brief recovery interval after firing when a neuron cannot fire or is harder to excite.

Neurotransmitter

Chemical messenger released by a neuron that binds receptors on another cell.

Reuptake

Reabsorption of released neurotransmitter into the sending neuron.

Multiple sclerosis (MS)

A disease that damages myelin in the CNS, disrupting nerve-signal transmission.

Myasthenia gravis

An autoimmune disorder disrupting acetylcholine signalling at neuromuscular junctions, causing weakness.

Acetylcholine (ACh)

Neurotransmitter important in skeletal muscle contraction, learning, and memory.

Dopamine

Neurotransmitter associated with motivation, reward learning, and movement.

Serotonin

Neurotransmitter that helps regulate mood, sleep, and appetite.

Norepinephrine

Neurotransmitter that supports alertness, attention, and arousal in stress.

GABA

The brain's major inhibitory neurotransmitter; reduces neural activity.

Glutamate

The brain's major excitatory neurotransmitter; important for learning and memory.

Endorphins

Natural opioid-like neurotransmitters that help reduce pain and can produce pleasurable feelings.

Substance P

Neuropeptide involved in transmitting pain signals.

Adrenaline (epinephrine)

Hormone that helps prepare the body for fight-or-flight by increasing heart rate and energy availability.

Ghrelin

Hormone that signals hunger; often rises before meals.

Leptin

Hormone released mainly by fat tissue that helps signal energy stores and fullness.

Oxytocin

Hormone involved in childbirth, milk release, and social bonding.

Melatonin

Hormone released by the pineal gland that helps signal night and regulate circadian timing.

Psychoactive drug

Substance that alters brain activity, affecting mood, perception, thinking, or behaviour.

Agonist

A drug that activates a receptor, producing a response like a natural neurotransmitter.

Antagonist

A drug that binds to a receptor and blocks its activation.

Depressants

Drugs that slow CNS activity; examples include alcohol and many sedatives.

Opioids

Drugs that act at opioid receptors, often reducing pain and creating overdose/dependence risks.

Stimulants

Drugs that increase CNS activity and alertness; examples include caffeine and cocaine.

Hallucinogens

Drugs that alter perception and sensory experience; examples include LSD and psilocybin.

Tolerance

Reduced effect of the same dose after repeated use; more may be needed for the same effect.

Withdrawal

Physical or psychological symptoms when a regularly used substance is reduced or stopped.

Medulla

Lower brainstem region regulating breathing, heart rate, and related automatic processes.

Pons

Brainstem region involved in sleep, arousal, and communication between brain regions.

Cerebellum

Coordinates balance, fine movement, posture, and motor learning.

Thalamus

Relays most incoming sensory information toward appropriate cortical regions.

Hypothalamus

Regulates homeostasis: hunger, thirst, body temperature, and many hormone-related functions.

Pituitary gland

Hormone-releasing gland closely regulated by the hypothalamus.

Amygdala

Limbic structure especially involved in emotion and threat processing.

Hippocampus

Crucial for forming new explicit/declarative memories.

Limbic system

Collection of connected structures involved in emotion, motivation, and memory.

Cerebral cortex

Outer layer of the cerebrum involved in higher perception, reasoning, and voluntary actions.

Frontal lobe

Cortical lobe involved in planning, judgement, decision-making, impulse control, and voluntary movement.

Parietal lobe

Cortical lobe that processes bodily touch and spatial information.

Temporal lobe

Cortical lobe important for hearing, language comprehension, and memory processing.

Occipital lobe

Main cortical region for visual processing.

Reticular formation

Brainstem network contributing to arousal and wakefulness.

Corpus callosum

Large bundle of nerve fibers connecting the left and right cerebral hemispheres.

Broca's area

Usually left frontal-lobe language region involved in speech production.

Broca's aphasia

Condition caused by damage to Broca's area, leading to effortful, nonfluent speech while comprehension remains relatively better preserved.

Wernicke's area

Usually left temporal-lobe region important for language comprehension.

Wernicke's aphasia

Condition caused by damage to Wernicke's area, impairing understanding and leading to fluent but often nonsensical speech.

Neuroplasticity

Ability of the brain to change connections or reorganize function through experience or after injury.

EEG

Technique where electrodes on the scalp record patterns of electrical brain activity; useful for sleep studies and epilepsy.

MRI

Technique that uses magnetic fields to create detailed images of brain structure.

fMRI

Technique that tracks changes in blood oxygenation related to brain activity while tasks are performed.

Dual processing

The principle that the mind processes information along both automatic and controlled tracks.

Stroop effect

Phenomenon where automatic word reading interferes with deliberately naming ink colours.

Circadian rhythm

Approximately $24\text{-hour}$ biological rhythm regulating sleep, hormones, temperature, and alertness.

Suprachiasmatic nucleus (SCN)

Hypothalamic biological clock that coordinates circadian rhythms with light information.

Social jetlag

Mismatch between a person's biological sleep timing and obligations like school or work.

NREM Stage 2

Light sleep stage characterized by sleep spindles and K-complexes on EEG.

NREM Stage 3

Deep, restorative slow-wave sleep dominated by delta waves; sleepwalking can occur.

REM sleep

Sleep stage marked by rapid eye movements, vivid dreaming, an active brain, and typical skeletal-muscle atonia.

Sleep spindle

Brief burst of rapid brain-wave activity that characterizes NREM Stage 2.

K-complex

Large, brief brain-wave pattern characteristic of NREM Stage 2.

Activation-synthesis theory

Theory that random neural firing from the pons is shaped by the cortex into a dream storyline.

Consolidation theory

Theory that dreaming is linked to processing, organizing, and strengthening memories from waking life.

Parasomnia

Abnormal or undesirable event or behaviour occurring during sleep.

Obstructive sleep apnea

Condition where repeated upper-airway blockage during sleep causes breathing interruptions and brief arousals.

CPAP

Continuous positive airway pressure; a machine that helps keep the airway open during sleep.

Somnambulism

Sleepwalking: moving or performing activities while still asleep, occurring in deep slow-wave NREM Stage 3.

REM sleep behaviour disorder (RBD)

Loss of normal REM muscle atonia leading to physical or vocal acting out of dreams.

Narcolepsy

Chronic disorder of sleep-wake regulation causing severe daytime sleepiness and sometimes sudden sleep episodes.

Orexin / hypocretin

Wakefulness-promoting neurochemical; loss of orexin neurons is associated with narcolepsy type 1.

Cataplexy

Sudden muscle weakness triggered by emotions such as laughter, especially in narcolepsy type 1.

CBT-I

Cognitive Behavioural Therapy for Insomnia; a first-line, structured treatment for persistent insomnia.

Prefrontal cortex

Forward region of the frontal lobe involved in higher-level thinking, executive functions, and personality.