AP Psychology Unit 1: Biological Bases of Behavior

Neuron

Basic nerve cell that receives, processes, and transmits information

Dendrites

Branch-like extensions that receive messages from other neurons

Soma (Cell Body)

Contains the nucleus and keeps the neuron functioning

Axon

Long fiber that carries neural impulses away from the soma

Myelin Sheath

Fatty covering around the axon that speeds up neural impulses

Nodes of Ranvier

Gaps in the myelin sheath where electrical signals jump to speed conduction

Axon Terminals (Terminal Buttons)

Ends of the axon that release neurotransmitters

Synapse (Synaptic Gap)

Small gap between neurons where neurotransmitters travel

Neurotransmitters

Chemical messengers that cross the synapse and bind to receptor sites

Reuptake

Process where the sending neuron reabsorbs excess neurotransmitters

Resting Potential

State when a neuron is negatively charged inside and not firing

Threshold

Minimum level of stimulation needed to trigger an action potential

Action Potential

Brief electrical impulse that travels down the axon

All-or-None Response

Neuron either fires completely or not at all

Refractory Period

Resting period after a neuron fires when it cannot fire again

Depolarization

Sodium ions rush into the neuron, making the inside more positive

Repolarization

Potassium ions move out to restore the neuron’s negative charge

Acetylcholine (ACh)

Neurotransmitter involved in muscle movement, learning, and memory

Low ACh Levels

Associated with Alzheimer’s disease

Dopamine

Neurotransmitter involved in movement, attention, emotion, and pleasure

High Dopamine Levels

Associated with schizophrenia

Low Dopamine Levels

Associated with Parkinson’s disease

Serotonin

Regulates mood, hunger, sleep, and arousal

Low Serotonin Levels

Associated with depression

Norepinephrine

Controls alertness and arousal during fight-or-flight responses

GABA

Major inhibitory neurotransmitter that calms neural activity

Low GABA Levels

Associated with anxiety, insomnia, and seizures

Glutamate

Major excitatory neurotransmitter important for memory and learning

High Glutamate Levels

Can overstimulate the brain, causing migraines or seizures

Endorphins

Natural painkillers linked to pleasure and pain control

Agonist

Drug or molecule that increases a neurotransmitter’s action

Antagonist

Drug or molecule that blocks a neurotransmitter’s action

Cerebrum

Largest brain region responsible for advanced thinking and voluntary actions

Cerebellum

Controls balance, coordination, and fine motor movement

Brainstem

Controls basic survival functions like breathing and heartbeat

Frontal Lobe

Responsible for decision-making, planning, personality, and voluntary movement

Motor Cortex

Controls voluntary body movements

Prefrontal Cortex

Responsible for planning, judgment, attention, and personality

Broca’s Area

Controls speech production

Broca’s Aphasia

Difficulty producing speech

Parietal Lobe

Processes sensory information and spatial awareness

Somatosensory Cortex

Processes touch, pressure, pain, and temperature

Temporal Lobe

Processes auditory information and language comprehension

Auditory Cortex

Processes sound information

Wernicke’s Area

Responsible for language comprehension

Wernicke’s Aphasia

Difficulty understanding language

Occipital Lobe

Processes visual information

Visual Cortex

Interprets visual signals from the eyes

Amygdala

Processes emotions such as fear and aggression

Hippocampus

Converts short-term memories into long-term memories

Hypothalamus

Controls hunger, thirst, body temperature, and the endocrine system

Thalamus

Sensory switchboard that relays all sensory information except smell

Basal Ganglia

Controls movement, habits, and procedural learning

Corpus Callosum

Connects the brain’s left and right hemispheres

Limbic System

Group of structures involved in emotion, motivation, and memory

Medulla

Controls heartbeat and breathing

Pons

Helps regulate sleep, breathing, and movement coordination

Reticular Formation

Controls arousal, alertness, and consciousness

Plasticity

Brain’s ability to reorganize and adapt through experience or injury

Endocrine System

Network of glands that release hormones into the bloodstream

Adrenal Glands

Release epinephrine and norepinephrine during stress

Central Nervous System (CNS)

Consists of the brain and spinal cord

Peripheral Nervous System (PNS)

All nerves outside the brain and spinal cord

Autonomic Nervous System

Controls involuntary body functions

Sympathetic Nervous System

Activates fight-or-flight responses

Parasympathetic Nervous System

Calms the body after stress

Somatic Nervous System

Controls voluntary body movements

CT Scan

Uses X-rays to create images of brain structure

MRI

Uses magnetic fields to show detailed brain structure

fMRI

Shows brain activity and function by tracking blood flow

PET Scan

Uses radioactive glucose to measure brain activity and metabolism

Consciousness

Awareness of thoughts, feelings, and surroundings

Circadian Rhythm

Internal 24-hour biological clock regulating sleep cycles

Suprachiasmatic Nucleus (SCN)

Controls circadian rhythms and melatonin release

Pineal Gland

Releases melatonin to regulate sleep cycles

Hypnosis

State of increased suggestibility and focused attention

NREM-1 Sleep

Light sleep stage with hypnagogic sensations and alpha waves slowing down

Hypnagogic Sensations

Feeling of falling or floating while falling asleep

NREM-2 Sleep

Stage marked by sleep spindles and K-complexes

Sleep Spindles

Bursts of brain activity that protect sleep

K-Complexes

Large brain-wave responses to stimuli during sleep

NREM-3 Sleep

Deep sleep stage characterized by delta waves

Delta Waves

Slow brain waves associated with deep sleep

REM Sleep

Stage with vivid dreams, rapid eye movements, and temporary paralysis

Paradoxical Sleep

REM sleep where the brain appears awake but the body is paralyzed

REM Rebound

Increase in REM sleep after REM deprivation

Memory Consolidation

Sleep strengthens and stores memories

Insomnia

Persistent difficulty falling or staying asleep

Narcolepsy

Sudden uncontrollable sleep attacks

Sleep Apnea

Repeated stopping of breathing during sleep

Night Terrors

Episodes of fear and panic during deep NREM-3 sleep

Sleepwalking

Walking during deep sleep, usually during NREM-3

Freud’s Wish-Fulfillment Theory

Dreams express hidden desires and conflicts

Manifest Content

Literal storyline of a dream

Latent Content

Hidden meaning of a dream

Activation-Synthesis Theory

Dreams result from the brain trying to make sense of random neural activity

Information-Processing Theory

Dreams help process and store memories from the day

Sensation

Detecting environmental stimuli and converting them into neural signals

Perception

Organizing and interpreting sensory information

Transduction

Conversion of physical stimuli into neural impulses