(2025) U1 AP Psychology Unit 1: Biological Basis of Behavior

AP Psychology

Sensory Neurons

Neurons that carry information from sensory receptors to the brain and spinal cord.

Interneurons

Neurons that process information within the central nervous system, acting as intermediaries between sensory and motor neurons.

Motor Neurons

Neurons that carry signals from the central nervous system to muscles and glands to produce movement or responses.

Central Nervous System

Composed of the brain and spinal cord, it processes and coordinates sensory input and motor output.

Peripheral Nervous System

Connects the CNS to the rest of the body, including sensory and motor neurons.

Reflex Arcs

Simple, automatic responses to stimuli that involve sensory neurons, interneurons, and motor neurons, bypassing the brain for speed.

Somatic Nervous System

This part of the peripheral nervous system controls voluntary movements and receives sensory information from the body. 

Autonomic Nervous System

Subsystem part of the PNS that controls involuntary functions like heart rate and digestion

Sympathetic Nervous System

Activates the body's "fight or flight" response during stress.

Parasympathetic Nervous System

Calms the body and conserves energy after stress.

Endocrine System

A collection of glands that secrete hormones into the bloodstream to regulate body functions.

Hormones

Chemical messengers that travel through the bloodstream to affect distant organs and tissues.

Epinephrine (Adrenaline)

Hormone released by the adrenal glands in response to stress, increasing heart rate and energy.

Leptin

Hormone that regulates appetite by signaling fullness.

Ghrelin

Hormone that stimulates hunger.

Melatonin

Hormone that regulates sleep-wake cycles.

Oxytocin

Hormone involved in bonding, social behaviors, and stress regulation.

Lesioning

The intentional destruction of brain tissue to study its functions or treat medical conditions.

Electroencephalogram (EEG)

A test that measures electrical activity in the brain using electrodes.

Functional MRI (fMRI)

measures the small changes in blood flow that occur with brain activity. It may be used to examine which parts of the brain are handling critical functions, evaluate the effects of stroke or other disease, or to guide brain treatment.

PET Scan

used to see metabolism (chemical activity) within your body. It can detect abnormal changes before structural changes occur.

CT Scan

It takes multiple cross-sectional images to show the “shape” of internal organs and other structures, such as bones and blood vessels. The images are then re-assembled, like a loaf of bread, and displayed on a computer monitor for a radiologist to “read” or interpret.

MRI

uses a powerful magnet and radio waves to create detailed images of organs and other structures inside your body.

Medulla

Part of the brain that controls essential autonomic functions like breathing, heart rate, blood pressure, and reflexes like swallowing and vomiting, while also serving as a pathway for nerve signals between the brain and spinal cord.

Cerebellum

Controls balance, coordination, and fine motor skills.

Reticular Formation

Responsible for consciousness. It transfers sensory signals such as pain and touch received by the ascending tracts to the cerebral cortex, thus causing wakefulness.

Thalamus

Acts as the brain's sensory relay station, directing sensory input to appropriate areas of the cerebral cortex.

Hypothalamus

Regulates basic bodily functions like hunger, thirst, and temperature and links the nervous system to the endocrine system.

Amygdala

the part of the brain that's most closely associated with fear, emotions, and motivation.

Hippocampus

involved in memory, learning, and emotion. Its largest job is to hold short-term memories and transfer them to long-term storage in our brains.

Brain Stem

Responsible for automatic survival functions like breathing and heartbeat.

Cerebral Cortex

The brain's outer layer, responsible for higher-order functions like thought, perception, and decision-making.

Limbic System

A group of interconnected brain structures that help regulate your emotions and behavior. The structures also work together with other brain regions by processing your memory, thoughts and motivations, then tell your body how to respond

Contralateral Hemispheric Organization

Each hemisphere of the brain controls the opposite side of the body.

Split-Brain Patients

Individuals with severed corpus callosum, showing unique effects on brain communication.

Corpus Callosum

The bundle of fibers connecting the two hemispheres, enabling communication between them.

Association Area

Regions of the cortex that integrate information and are involved in complex processes like thinking and memory.

Frontal Lobe

Lobe of the brain responsible for control over many abilities, including the way you think, how you move and how you remember things. It's also a key part in your social skills, and helps you understand and control how you talk, behave and interact with others.

Prefro

Broca’s Area

region of the brain that contains neurons involved in speech function.

Aphasia

a language disorder caused by damage to parts of the brain that control speech and understanding of language.

Wernicke’s Area

region of the brain that contains motor neurons involved in the comprehension of speech

Motor cortex

the region of the cerebral cortex involved in the planning, control, and execution of voluntary movements.

Parietal Lobes

part of the brain that processes your sense of touch and assembles input from your other senses into a form you can use.

Somatosensory Cortex

Processes sensory input like touch, pain, and temperature.

Phantom Limb Syndrome

a nonpainful perception of the continued presence of an amputated limb. It is part of a deafferentation syndrome, in which there is loss of sensory input secondary to amputation.

Occipital Lobes

part of the brain that processes visual information

Temporal Lobes

Part of the brain that processes auditory information and language comprehension

Linguistic Processing

The brain's ability to understand and produce language.

Genetic Predisposition

a tendency for certain traits to be inherited, including physical and mental conditions and disorders.

Neuron

Information messengers. They use electrical and chemical signals to send information between different areas of the brain, as well as between the brain, the spinal cord, and the entire body.

Multiple Sclerosis

A disorder of the central nervous system marked by weakness, numbness, a loss of muscle coordination, and problems with vision, speech, and bladder control. Additionally damages the myelin sheath, disrupting neural communication

Neural Transmission

The process of sending signals between neurons

Resting Potential

the electric potential across the plasma membrane of a neuron when it is in the nonexcited, or resting, state.

Threshold

The level of stimulation required to trigger an action potential.

Action Potential

the change in electric potential that propagates along the axon of a neuron during the transmission of a nerve impulse or the contraction of a muscle.

All or None Principle

the principle that neurons either fire completely or not at all.

Depolarization

A reduction in the neuron’s negative charge, triggering an action potential.

Excitatory Signals

electrical signals that increase the likelihood that a neuron will fire an action potential.

inhibitory signals

signals in the nervous system that decrease the likelihood of a neuron firing an action potential, or "message."

Dopamine

Involved in reward, motivation, and motor control; imbalances linked to Parkinson's and schizophrenia.

Serotonin

Regulates mood, sleep and appetite

Norepinephrine

Affects alertness and arousal

Glutamate

Major excitatory neurotransmitter, critical for learning and memory.

GABA

a neurotransmitter, a chemical messenger in your brain. It slows down your brain by blocking specific signals in your central nervous system (your brain and spinal cord).

Endorphins

neurotransmitters released by the pituitary gland and hypothalamus in the brain. As natural hormones, they can alleviate pain, lower stress, improve mood, and enhance your sense of well-being.

Substance P

a neurotransmitter present in the brain and spinal cord, where it is known to be involved in pain signaling.

Acetylcholine

Involved in memory, learning, and muscle contractions; deficits linked to Alzheimer’s.

Alzheimer’s Disease

a brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks.

Myasthenia Gravis

a chronic autoimmune disorder in which antibodies destroy the communication between nerves and muscle, resulting in weakness of the skeletal muscles.

Priming

Prior exposure to a stimulus influences the response to a related stimulus without conscious awareness (e.g., seeing "yellow" makes "banana" easier to recognize).

Blindsight

The ability to respond to visual stimuli without consciously perceiving them, often due to damage in the visual cortex.

Consciousness

Awareness of internal and external experiences, including thoughts, sensations, and the environment.

Psychoactive Drugs

Substances that affect the brain, altering mood, perception, or behavior (e.g., stimulants, depressants).

Agonists

Chemicals that mimic or enhance the action of neurotransmitters by activating their receptors.

Antagonists

Chemicals that block or inhibit the action of neurotransmitters by occupying their receptors.

Reuptake

The process where neurotransmitters are reabsorbed by the neuron that released them, ending their action.

Tolerance

The need for increasing doses of a drug to achieve the same effect due to repeated use.

Withdrawal

Physical or psychological symptoms that occur when stopping or reducing the use of an addictive substance.

Caffeine

A stimulant that blocks adenosine receptors, increasing alertness and reducing drowsiness.

Cocaine

A stimulant that increases dopamine levels, leading to euphoria and energy but with high addiction potential.

Stimulants

Drugs that increase brain activity, boosting alertness and energy (e.g., caffeine, nicotine, amphetamines).

Alcohol

A depressant that slows brain activity, reducing inhibitions and promoting relaxation but impairing motor skills.

Depressants

Drugs that decrease central nervous system activity, causing sedation and relaxation (e.g., alcohol, benzodiazepines).

Hallucinogens

Drugs that alter perception, thoughts, and sensations, often causing hallucinations (e.g., LSD, psilocybin).

Marijuana

A psychoactive drug from the cannabis plant; it can cause relaxation, altered perception, and euphoria. It also has medical purposes as its used to ease symptoms caused by certain medical conditions.

Opiates

Drugs derived from opium that relieve pain and produce euphoria by binding to opioid receptors (e.g., morphine, codeine).

Heroin

a highly addictive analgesic drug derived from morphine, often used illicitly as a narcotic producing euphoria.

Circadian Rhythm

The 24-hour biological clock regulating sleep, wakefulness, and other bodily processes.

NREM stage 1

Light sleep where you drift in and out, characterized by slowed heartbeat and relaxed muscles.

NREM Stage 2

Deeper sleep with slower brain activity and sleep spindles (brief bursts of brain activity).

NREM Stage 3

Deep sleep (slow-wave sleep) critical for physical restoration and immune function.

Restoration of resources

The theory that sleep replenishes energy and repairs the body and brain.

REM/Paradoxical Sleep

Sleep stage with vivid dreams, rapid eye movements, and heightened brain activity.

REM Rebound

Increased REM sleep after being deprived of it, often with more vivid dreams.

Insomnia

Difficulty falling or staying asleep, often causing fatigue and cognitive issues.

Narcolepsy

A sleep disorder where people experience sudden, uncontrollable sleep episodes during the day.

Sleep Apnea

A disorder where breathing repeatedly stops and starts during sleep, leading to poor rest.

Somnambulism

Sleepwalking, a condition where a person performs activities while in deep sleep.

Activation Synthesis Theory

The idea that dreams result from the brain's attempt to make sense of random neural activity during sleep.