PSYC 100 - CH 3 and 9

Neurons

Cells that communicate via electrical and chemical signals.

Soma (cell body)

The cell's life support, containing the nucleus.

Dendrites

Branches that receive messages from other cells.

Axon

Passes messages away from the cell body to other neurons, muscles, or glands.

Myelin sheath

Covers the axon of some neurons and helps speed neural impulse.

Nodes of Ranvier

Gaps in the myelin sheath that speed up electrical impulse transmission.

Terminal buttons

Small knobs at the end of axons that release neurotransmitters.

Synapse

The junction between two neurons where neurotransmitters are exchanged.

Receptors

Protein structures on the postsynaptic neuron that bind to neurotransmitters.

Resting potential

The stable, negative charge of a neuron when it is inactive (~–70 mV).

Threshold

The level of stimulation required to trigger an action potential.

Action potential

A brief electrical charge that travels down the axon when a neuron fires.

Sodium and potassium

Ions that move across the neuron's membrane to generate and reset action potentials.

Refractory period

A short time after firing when a neuron cannot fire again.

All-or-none law

A neuron either fires completely or not at all, with no partial action potentials.

Reuptake

The process by which neurotransmitters are reabsorbed by the presynaptic neuron.

Excitatory transmitters

Neurotransmitters that increase the likelihood of the postsynaptic neuron firing.

Inhibitory transmitters

Neurotransmitters that decrease the likelihood of the postsynaptic neuron firing.

Acetylcholine

Neurotransmitter involved in muscle movement, memory, and learning.

Dopamine

Neurotransmitter linked to reward, motivation, and motor control.

Glutamate

The brain’s main excitatory neurotransmitter, involved in learning and memory.

GABA (gamma-aminobutyric acid)

The brain’s main inhibitory neurotransmitter, helps regulate anxiety.

Norepinephrine

Neurotransmitter involved in alertness, arousal, and the fight-or-flight response.

Serotonin

Regulates mood, appetite, sleep, and emotional states.

Endorphins

Natural painkillers that promote pleasure and reduce discomfort.

Agonists

Chemicals that mimic or enhance the effects of neurotransmitters.

Antagonists

Chemicals that block or reduce the effects of neurotransmitters.

Central nervous system (CNS)

Composed of the brain and spinal cord; processes sensory information.

Peripheral nervous system (PNS)

All nerves outside the CNS; connects CNS to limbs and organs.

Somatic system

Controls voluntary movements and sensory input.

Autonomic system

Regulates involuntary functions like heart rate and digestion.

Sympathetic system

Activates fight-or-flight response.

Parasympathetic system

Calms the body and conserves energy post-stress.

Spinal reflexes

Automatic responses to stimuli occurring via the spinal cord.

Medulla

Located at the base of the brain stem; controls heartbeat and breathing.

Reticular formation

Regulates arousal and consciousness.

Pons

Coordinates movement, located above the medulla.

Cerebellum

Coordinates voluntary movement and life-sustaining functions.

Midbrain

Involved in eye movement and serves as a dopaminergic center.

Blindsight

Responding to visual stimuli without conscious awareness.

Forebrain

Largest brain region; includes cerebral cortex and subcortical structures.

Cerebral cortex

Includes two hemispheres and four lobes: frontal, parietal, occipital, and temporal.

Grey matter

Contains neuron cell bodies; involved in processing and cognition.

White matter

Made of myelinated axons; facilitates communication between brain regions.

Thalamus

Directs sensory messages to the cortex and maintains homeostasis.

Hypothalamus

Regulates the Four F’s: fight, fleeing, food, and reproduction.

Hippocampus

Processes new explicit memories; decreases in size with age.

Amygdala

Linked to emotion; contains two lima-bean-sized neural clusters.

Basal ganglia

Involved in movement regulation and habit formation.

Split brain patient

Individuals with severed corpus callosum; studied for hemispheric specialization.

Henry Molaison

Key subject in memory studies post-hippocampus removal.

Phineas Gage

Individual whose personality changes after a frontal lobe injury revealed cortex role.

Endocrine system

Hormone-regulating system that influences growth and mood.

Pituitary gland

The master gland controlling other glands and regulating growth.

DNA

Carries genetic instructions for development and functioning.

Chromosomes

Structures made of DNA containing genes.

Epigenetics

Studies how the environment affects gene expression without changing DNA.

Adoption studies

Research assessing genetic influence by comparing adopted children to biological parents.

Twin studies

Comparative research on identical and fraternal twins to estimate genetic versus environmental influence.

Monozygotic (Identical) twins

Twins from one fertilized egg; share 100% of genes.

Dizygotic (Fraternal) twins

Twins from two fertilized eggs; share ~50% of genes.

Heritability

Proportion of variation in traits due to genetic factors.

Caveats about heritability

Does not apply to individuals; varies by population and environment.

Shared environment

Environmental factors that siblings share.

Non-shared environment

Unique experiences that differ among siblings.

3 laws of behavior genetics

1. All human traits are heritable. 2. Family effects are smaller than genetic. 3. Variation in traits unexplained by genes or shared environment.

Somato-sensory cortex

Processes touch and body position; located in the parietal lobe.

Mirror neurons

Fire when performing or observing an action; linked to empathy.

Brain plasticity

The brain's ability to change and adapt through experience or injury.

Cultural neuroscience

Studies the interaction of culture and biology on brain function.

Broca’s area

Region in the left frontal lobe responsible for speech production.

Wernicke’s area

Region in the left temporal lobe involved in language comprehension.

Left hemisphere

Handles language and logic.

Right hemisphere

Specializes in spatial, emotional, and creative tasks.

Corpus callosum

A thick band of nerve fibers connecting the two hemispheres.

Frontal lobes

Involved in decision-making, planning, problem-solving, and personality.

Occipital lobes

Located at the back of the brain; primarily responsible for visual processing.

Parietal lobes

Processes sensory information like touch and spatial awareness.

Temporal lobes

Handle auditory processing, language comprehension, and memory formation.

Motor cortex

Part of the frontal lobe responsible for planning and executing voluntary movements.

Motor humunculous

Representation of the body in the brain, showing areas of sensitivity.

EEG (electroencephalography)

Measures and records electrical activity in the brain.

CT scan

Uses X-rays to create detailed brain images for injury detection.

MRI

Uses magnetic fields to produce high-resolution images of brain structure.

fMRI

Measures brain activity by detecting changes in blood flow.

PET

Tracks radioactive tracers to show brain activity.

Transcranial magnetic stimulation (TMS)

Uses magnetic fields to stimulate or inhibit brain regions.

Language

A structured system of communication using symbols (spoken, written, or signed) governed by rules.

Generativity

The ability to produce an infinite number of sentences from a finite set of elements.

Grammar

The set of rules that govern the structure of language, including syntax and morphology.

Phoneme

The smallest unit of sound that can distinguish meaning in a language.

Morpheme

The smallest unit of meaning in a language (e.g., 'un-', '-ed').

Syntax

Rules that govern the arrangement of words into sentences.

Semantics

The study of meaning in language.

Pragmatics

The study of how context influences language use and interpretation.

Telegraphic speech

Early speech stage where children use short, content-rich phrases (e.g., 'want toy').

Overgeneralization

Applying grammatical rules too broadly (e.g., 'goed' instead of 'went').

B.F. Skinner

Behaviorist who believed language is learned through reinforcement and imitation.

Behaviorism

A theory that behavior is learned through conditioning and environmental stimuli.

Noam Chomsky

Linguist who proposed that humans have an innate ability to acquire language.