AP Psychology: Unit 1

Neuron

Individual cells in the nervous system that receive, integrate, and transmit information; the basic communication units.

Soma

Cell body of the neuron that contains the nucleus and major cellular organelles.

Dendrite

Branch-like parts of a neuron that receive information from other neurons.

Axon

Long fiber that transmits information away from the neuron to other neurons, muscles, or glands.

Myelin Sheath

Insulating layer around some axons that speeds neural transmission.

Terminal Button

Knobs at the end of an axon where neurotransmitters are released to activate neighboring neurons.

Synapse

Junction where information is transmitted from one neuron to another.

Glia

Support cells in the nervous system that nourish neurons, remove waste, and insulate axons.

Neurotransmitters

Chemicals that transmit information across the synaptic cleft from one neuron to another.

Acetylcholine

Neurotransmitter between motor neurons and voluntary muscles; involved in muscle activation.

Dopamine

Monoamine involved in movement control and reward; degeneration linked to Parkinson's and overactivity linked to schizophrenia.

Norepinephrine

Monoamine involved in arousal and mood; low levels linked to depression.

Serotonin

Monoamine involved in sleep, wakefulness, and eating behavior; imbalance linked to mood disorders.

GABA

Gamma-aminobutyric acid; the main inhibitory neurotransmitter in the brain; reduces neural excitability.

Endorphins

Endogenous opioids that modulate pain and produce other effects; act on endorphin receptors.

Agonist

Chemical that mimics the action of a neurotransmitter and enhances PSPs.

Antagonist

Chemical that opposes the action of a neurotransmitter and blocks PSPs.

Monoamines

Class of neurotransmitters including dopamine, norepinephrine, and serotonin.

Receptor Site

Location on the postsynaptic neuron where neurotransmitters bind to produce effects.

Reuptake

Process by which neurotransmitters are reabsorbed into the presynaptic neuron.

Presynaptic Neuron

Neuron that sends the signal across the synapse.

Postsynaptic Neuron

Neuron that receives the signal at its receptors.

PSP (Postsynaptic Potential)

Voltage change at the postsynaptic membrane; graded, not all-or-none.

Excitatory PSP

PSP that increases the likelihood that the postsynaptic neuron will fire an action potential.

Inhibitory PSP

PSP that decreases the likelihood that the postsynaptic neuron will fire a neuron.

Absolute Refractory Period

Minimum time after an action potential during which another action potential cannot begin (about 1–2 ms).

All-Or-None Law

Neural impulses fire completely or not at all; rate conveys stimulus strength.

Synaptic Cleft

Gap between the terminal button of one neuron and the membrane of the next.

Synaptic Vesicles

Vessels in the presynaptic terminal that contain neurotransmitters.

Central Nervous System

Brain and spinal cord; protected by meninges and cerebrospinal fluid.

Peripheral Nervous System

Nerves outside the brain and spinal cord.

Somatic Nervous System

Nerves that connect to voluntary muscles and sensory receptors; includes afferent and efferent fibers.

Autonomic Nervous System

Nerves that regulate involuntary bodily functions; divided into sympathetic and parasympathetic divisions.

Sympathetic Division

Mobilizes body resources for emergencies ('fight or flight').

Parasympathetic Division

Conserves bodily resources and returns the body to calm after arousal.

Medulla

Hindbrain structure that controls vital functions like breathing and heart rate.

Pons

Bridge of fibers connecting the brainstem to the cerebellum; involved in sleep and arousal.

Cerebellum

Brain region that coordinates movement, balance, and is affected by alcohol.

Reticular Formation

Network in the hindbrain and midbrain contributing to arousal, sleep, and reflexes.

Thalamus

Sensory relay station through which all senses (except smell) pass to the cortex.

Hypothalamus

Regulates basic biological needs; controls autonomic nervous system and endocrine system; governs basic drives (five F's: fighting, fleeing, feeding, mating).

Limbic System

Emotion, memory, and motivation circuitry; loosely connected network in the brain.

Cerebrum

Largest brain region; involved in learning, memory, thinking, and conscious experience.

Cerebral Cortex

Wrinkled outer layer of the cerebrum responsible for higher-order processing.

Corpus Callosum

Bundle of fibers connecting the two cerebral hemispheres.

Occipital Lobe

Lobe at the back of the brain; primary visual cortex (sense of sight).

Parietal Lobe

Lobe responsible for primary somatosensory cortex (sense of touch).

Temporal Lobe

Lobe responsible for primary auditory cortex (sense of hearing).

Frontal Lobe

Lobe containing the primary motor cortex; important for planning and executing movements.

Plasticity

Experience shapes brain structure; younger brains are more malleable; damage can lead to reorganization.

Split-Brain

Surgical severing of the corpus callosum to reduce seizures; hemispheres operate independently.

Roger Sperry

Nobel Prize-winning researcher known for split-brain studies in the 1960s.

Hemispheric Specialization

Left hemisphere tends to handle language; right hemisphere tends to handle nonverbal and spatial tasks.

Endocrine System

Glands that secrete hormones into the bloodstream to regulate bodily functions.

Hormones

Chemical messengers released by glands; slower than neurotransmitters but have lasting effects.

Pituitary Gland

Master gland; releases hormones and is regulated by the hypothalamus.

Meninges

Protective layers covering the brain and spinal cord; inflammation leads to meningitis.

Cerebrospinal Fluid

Fluid that nourishes the brain and spinal cord and provides cushioning.

Meningitis

Inflammation of the meninges, often due to infection.

Electroencephalograph (EEG)

Device that records the brain's electrical activity via scalp electrodes.

Lesioning

Destroying brain tissue to study its function (often in animals).

Electrical Stimulation of the Brain (ESB)

Applying a weak electrical current to a brain region to activate it.

Transcranial Magnetic Stimulation (TMS)

Magnetic stimulation used to temporarily enhance or depress activity in a brain area.

Brain-Imaging Procedures

Techniques like CT, PET, and MRI that visualize brain structure and function.

Darwin

Natural selection and fitness as driving forces in evolution.

Fitness

The reproductive success of an organism in comparison to others in the population.

Natural Selection

Heritable traits that confer survival or reproductive advantages become more common.

Dobzhansky

Genetic perspective on evolution integrating Mendel's work with Darwinian theory.

Adaptation

Inherited characteristic that increases a population's survival or reproduction.

Inclusive Fitness

An individual's own reproductive success plus the impact on relatives' reproductive success.

Polygenic Traits

Traits influenced by multiple genes across the genome.

Oxytocin

A hormone and neurotransmitter involved in social bonding, trust, sexual arousal, and maternal behaviors like childbirth and lactation. Often called the "love hormone."

Adrenaline (Epinephrine)

A hormone secreted by the adrenal glands, involved in the "fight or flight" response, increasing heart rate, blood pressure, and energy supply in emergencies.

Melatonin

A hormone primarily produced by the pineal gland that regulates sleep-wake cycles and influences circadian rhythms.

Ghrelin

A hormone produced by the stomach that stimulates appetite; often referred to as the "hunger hormone."

Leptin

A hormone produced by fat cells that signals satiety to the brain, suppressing appetite and regulating energy balance; often referred to as the "satiety hormone.""

Sensation

The stimulation of sense organs.

Perception

The selection, organization, and interpretation of sensory input.

Psychophysics

Study of how physical stimuli are translated into psychological experience.

Absolute Threshold

Minimum stimulus intensity that an organism can detect.

Just Noticeable Difference (JND)

The smallest difference in stimulus intensity that a specific sense can detect.

Weber’s Law

The size of a JND is a constant proportion of the initial stimulus.

Weber’s Fraction

Fractions that apply to different sensory inputs until a difference is noted; increases proportionally.

Signal-Detection Theory

Detection of stimuli involves decision processes and sensory processes, influenced by factors beyond stimulus intensity.

Noise

Background distractions that lower the chance of detecting a stimulus.

Subliminal Perception

Registration of sensory input without conscious awareness.

Sensory Adaptation

Gradual decline in sensitivity to prolonged stimulation.

Light

A form of electromagnetic radiation that travels as a wave at the speed of light.

Amplitude

Affects brightness (height) of light.

Wavelength

Affects perceived color (distance between peaks of a wave).

Retina

Neural tissue lining the inside back surface of the eye; absorbs light, processes images, and sends visual information to the brain; part of the CNS.

Lens

Transparent eye structure that focuses light rays onto the retina.

Nearsightedness (Myopia)

Nearby objects are clear; distant objects appear blurry.

Farsightedness (Hyperopia)

Distant objects are clear; nearby objects appear blurry.

Pupil

The opening in the center of the iris that permits light to pass into the rear chamber of the eye.

Iris

Controls the size of the pupil and the amount of light entering the eye.

Optic Disk

Holes in the retina where the optic nerve fibers exit the eye.

Rods

Photoreceptors that are important for night and peripheral vision; outnumber cones.

Cones

Photoreceptors that are important for daylight and color vision; concentrated in the fovea.

Fovea

Tiny spot in the center of the retina that contains only cones; visual acuity is best here.