Biological Bases of Behavior

Psychoactive drugs

Chemical substances that alter perceptions and moods.

Agonists

Molecules that increase a neurotransmitter's action by mimicking it or blocking reuptake.

Antagonists

Molecules that inhibit or block a neurotransmitter's action.

Reuptake inhibitors

Drugs that interfere with the reabsorption of neurotransmitters, leaving more in the synapse.

Stimulants

Drugs (like Caffeine and Cocaine) that excite neural activity and speed up body functions.

Depressants

Drugs (like Alcohol) that reduce neural activity and slow body functions.

Hallucinogens

Psychedelic drugs (like Marijuana—specifically THC) that distort perceptions and evoke sensory images.

Opioids

Drugs (like Heroin) derived from opium that depress neural activity, temporarily relieving pain and anxiety.

Tolerance

The diminishing effect with regular use of the same dose of a drug.

Addiction

Compulsive craving for drugs or certain behaviors despite known adverse consequences.

Withdrawal

The discomfort and distress that follow discontinuing an addictive drug or behavior.

Brain stem

The oldest part and central core of the brain, responsible for automatic survival functions.

Medulla

The base of the brainstem that controls heartbeat and breathing.

Reticular activating system (RAS)

A nerve network in the brainstem that plays an important role in controlling arousal/alertness.

Cerebellum

The 'little brain' at the rear of the brainstem; processes sensory input, coordinates movement, and balance.

Cerebral cortex

The intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center.

Limbic system

Neural system including the hippocampus, amygdala, and hypothalamus; associated with emotions and drives.

Thalamus

The brain's sensory control center that directs messages to sensory receiving areas in the cortex.

Hypothalamus

Directs maintenance activities and governs the endocrine system via the Pituitary gland; linked to emotion and reward.

Hippocampus

A neural center in the limbic system that processes explicit (conscious) memories.

Amygdala

Two lima-bean-sized neural clusters in the limbic system linked to emotion, specifically fear and aggression.

Corpus callosum

The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

Occipital lobes

At the back of the head; includes areas that receive information from the visual fields.

Temporal lobes

Roughly above the ears; includes auditory areas.

Parietal lobes

At the top/rear; receives sensory input for touch and body position.

Frontal lobes

Behind the forehead; involved in speaking, muscle movements, and making plans/judgments.

Association areas

Areas of the cerebral cortex not involved in primary motor or sensory functions; involved in higher-order thinking and linguistic processing.

Executive functioning

High-level cognitive processes managed primarily by the prefrontal cortex.

Somatosensory cortex

Area at the front of the parietal lobes that registers and processes body touch and movement sensations.

Motor cortex

Area at the rear of the frontal lobes that controls voluntary movements.

Hemispheric specialization

The tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other.

Split brain research

Studies of patients whose corpus callosum has been severed, revealing the independent functions of the two hemispheres.

Broca’s area

Controls language expression; located in the left frontal lobe and directs muscle movements involved in speech.

Wernicke’s area

Controls language reception; a brain area involved in language comprehension, usually in the left temporal lobe.

Aphasia

Impairment of language; Broca's aphasia results in difficulty speaking, while Wernicke's aphasia results in difficulty understanding or producing meaningful speech.

Contralateral hemispheric organization

The setup where the left side of the brain controls the right side of the body, and vice versa.

Plasticity

The brain’s ability to change, particularly during childhood, by reorganizing after damage or by building new pathways.

EEG (Electroencephalogram)

An amplified recording of the waves of electrical activity sweeping across the brain's surface.

fMRI (Functional MRI)

A technique for revealing blood flow and brain activity by comparing successive MRI scans.

Lesioning

Purposefully destroying tiny clusters of normal or defective brain cells to observe the effects on behavior.

Consciousness

Our subjective awareness of ourselves and our environment.

Circadian rhythm

Our biological clock; regular bodily rhythms that occur on a 24-hour cycle.

Jet lag

A temporary sleep disorder caused by traveling across time zones, disrupting the circadian rhythm.

Shift work

Work schedules outside the standard 9-to-5, which can disrupt sleep patterns.

NREM stage 1

The transition from wakefulness to sleep; may involve hypnogogic sensations.

NREM stage 2

Characterized by sleep spindles, bursts of rapid brain activity.

NREM stage 3

Deep sleep characterized by slow delta waves.

REM sleep

Rapid Eye Movement sleep; a recurring sleep stage during which vivid dreams commonly occur.

REM rebound

The tendency for REM sleep to increase following REM sleep deprivation.

Activation-synthesis theory

The theory that dreams are the brain's attempt to synthesize random neural activity.

Consolidation theory / Memory consolidation

The idea that sleep helps process experiences into long-term memory.

Restoration of resources

Theory that sleep allows the body and brain to repair and replenish chemical and physical resources.

Insomnia

Persistent problems in falling or staying asleep.

Narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks.

REM sleep behavior disorder

A condition where the paralysis associated with REM sleep is absent, causing the person to act out their dreams.

Sleep apnea

A disorder where the person stops breathing for brief periods while asleep.

Somnambulism

Sleepwalking; occurs during NREM-3 deep sleep.