Unit 1: Biological Bases for Behavior

Brain stem

the oldest and innermost region of the brain that connects the spinal cord to the higher brain regions and controls automatic, life-sustaining survival functions

Medulla

the base of the brainstem that automatically controls vital, life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion

Reticular activation system

a diffuse network of nerve pathways running through the center of the brainstem (spanning the medulla, pons, and midbrain) that controls arousal, alertness, and wakefulness

Reward Center

a network of brain structures that regulates pleasure, motivation, reinforcement, and goal-directed behavio

Cerebellum

a structure located at the rear base of the brain (in the hindbrain) that coordinates voluntary muscle movements, posture, and balance, while also playing a role in procedural learning

Cerebral cortex

is the outer layer of gray matter on the cerebrum, responsible for higher-level processes like thinking, language, memory, and voluntary movement

Limbic system

a complex network of neural structures located deep within the brain, beneath the cerebral cortex and above the brainstem. It plays a central role in regulating emotions, memory, and basic drives (such as hunger, thirst, and sex) necessary for survival

Thalamus

the brain's sensory switchboard or relay station, located directly on top of the brainstem in the middle of the brain

Hypothalamus

a small brain structure located just below the thalamus that maintains the body's internal balance (homeostasis) by regulating basic biological drives and controlling the endocrine system

Pituitary gland

a pea-sized structure located at the base of the brain, just beneath the hypothalamus, known as the "master gland" of the endocrine system because it releases hormones that regulate growth and control other endocrine glands

Hippocampus

a seahorse-shaped structure in the limbic system of the brain responsible for forming and consolidating new explicit (declarative) long-term memories and supporting spatial navigation

Amygdala

an almond-shaped cluster of neurons located in the limbic system within the temporal lobes of the brain. It processes emotions, triggers survival responses, and links strong feelings to memories.

corpus callosum

a thick band of neural (nerve) fibers that connects the left and right cerebral hemispheres of the brain, allowing them to communicate and share information. [1, 2]

Occipital lobes

rearmost region of the cerebral cortex responsible for processing visual information, including color, shape, depth, and motion

Temporal lobes

regions of the cerebral cortex located on the sides of the brain, right above the ears, that process auditory information and language comprehension

Parietal lobes

sits at the top and back of the head (behind the frontal lobe and above the temporal lobe) and processes sensory input, body position, and spatial awareness

Associaion areas

regions of the cerebral cortex that do not perform primary motor or sensory functions, instead integrating, processing, and connecting higher-level mental tasks like learning, thinking, remembering, and speaking

Somatosensory cortex

a strip of the cerebral cortex located at the front of the parietal lobe, just behind the central sulcus and parallel to the motor cortex. The somatosensory cortex. Itprocesses physical sensations from the body, including touch, pain, temperature, pressure, and proprioception (body position)

Frontal lobes

the region of the cerebral cortex located right behind your forehead, responsible for higher-level thinking, executive functions, and voluntary movement

Motor cortex

is a region at the rear of the frontal lobe that controls voluntary skeletal muscle movements

Split-brain research

the study of patients who have had their corpus callosum—the bundle of nerve fibers connecting the left and right brain hemispheres—severed (a procedure called a callosotomy), typically to treat severe, untreatable epilepsy

Hemispheric specialization

is the idea that the left and right hemispheres of the brain have distinct, specialized functions, even though they work together constantly

Broca's area

a critical region in the left frontal lobe of the brain responsible for speech production and language expression

Wernicke's area

the region of the brain responsible for language comprehension and understanding spoken or written words

Aphasia

an impairment of language, usually caused by left-hemisphere damage to specific brain areas responsible for speech production or comprehension

Contralateral hemispheric organization

each side of the brain (cerebral hemisphere) processes sensory input from and controls motor movements for the opposite side of the body

Plasticity

the brain's ability to change, reorganize, and form new neural pathways in response to learning, experience, or recovery from injury

EEG

a non-invasive tool used in AP Psychology to measure the electrical activity of the brain's surface

Lesioning

the naturally or experimentally caused destruction of brain tissue

consciousnesss

our subjective, moment-to-moment awareness of ourselves and our environment

Circadian rhythm

your body's internal, roughly 24-hour biological clock that regulates processes like the sleep-wake cycle, hormone release, and body temperature

Jet lag

a temporary physical and mental condition caused by a mismatch between your internal biological clock and the time zone of your new location

Shift work and how it impacts circidian rhythm

any employment schedule that falls outside the traditional daytime 9-to-5 workday, including evenings, nights, early mornings, or rotating shifts. It disrupts your circadian rhythm—the body's roughly 24-hour internal biological clock managed by the suprachiasmatic nucleus (SCN) in the hypothalamus

NREM stage 1

the brief, lightest stage of sleep that marks the transition from wakefulness to sleep

Hypnagogic sensations

lifelike, bizarre sensory experiences—such as feeling like you are falling, floating, or hearing a sudden noise—that occur as you transition from wakefulness into Stage 1 (NREM-1) sleep

NREM stage 2

a period of true sleep onset where the body deepens its rest, making up about 45% to 55% of an adult's total sleep time

Sleep spindles

brief, rapid bursts of rhythmic brain-wave activity that appear on an EEG during NREM Stage 2 sleep

REM stage sleep

a unique stage of the sleep cycle marked by fast, wake-like brain activity, rapid eye movements, and vivid dreaming

REM rebound

the tendency for your body to spend more time in—and enter more quickly into—REM (Rapid Eye Movement) sleep after you have been deprived of it

Activation-synthesis

a biological theory of dreaming stating that dreams are the cerebral cortex's attempt to make sense of random neural signals fired from the brainstem during REM sleep

Consolidation theory

sleep and dreaming help stabilize and strengthen fragile short-term memories into durable long-term memories

Memory consolidarion

the physiological and psychological process that stabilizes newly encoded, fragile information into durable, long-term memory over time.

Insomnia

a recurring sleep disorder characterized by persistent difficulty falling asleep, staying asleep, or waking up too early and being unable to return to sleep, despite having adequate opportunity to rest

Narcolepsy

neurological sleep disorder characterized by excessive daytime sleepiness and sudden, uncontrollable "sleep attacks" that often plunge a person directly into REM sleep

REM sleep behavior disorder

a parasomnia where individuals physically act out vivid, unpleasant dreams with vocal sounds and violent limb movements because the brain fails to paralyze the muscles during REM sleep

Sleep apnea

a sleep disorder characterized by temporary, repeated cessations of breathing during sleep and brief, momentary awakenings

somnabulism (sleep walking)

a parasomnia disorder where a person performs complex motor behaviors—such as walking or talking—while largely asleep and unresponsive.