Intro to Psych Quest 1

​​Neurons

basic units of the nervous system, communicate via electrical & chemical signals.

Cell body (soma)

keeps neuron alive.

Dendrites

receive signals.

Axon

carries signal away.

Myelin sheath

Insulates axon, speeds transmission.

Nodes of Ranvier

gaps where ion channels regenerate action potential.

Terminal buttons

release neurotransmitters into the synapse.

Action potential

electrical impulse along axon.

Resting membrane potential .

neuron’s baseline charge

Absolute refractory period

can’t fire again immediately.

Relative refractory period

harder, but possible, to fire.

All-or-none principle

fires completely or not at all.

Brain stem

survival functions (heart rate, breathing).

Cerebellum

motor coordination, balance.

Thalamus

sensory relay station.

Basal ganglia

movement, reward.

Amygdala

fear, emotion.

Hippocampus

memory.

Hypothalamus

regulates hunger, sex, body temp.

Cerebral cortex

higher thought.

Frontal lobes

planning, decision making.

Parietal lobes

touch, spatial awareness.

Occipital lobes

vision.

Temporal lobes

hearing, language.

Prefrontal cortex

personality, rational thought.

Broca’s area

speech production.

Insula

internal body states (like disgust).

Corpus callosum

connects hemispheres in brain

Central nervous system (CNS)

brain + spinal cord.

Peripheral nervous system (PNS)

everything else.

Somatic (SNS)

voluntary movement.

Autonomic (ANS)

involuntary (organs, glands).

Sympathetic

fight or flight

Parasympathetic – rest

rest and digest

Endocrine system

glands release hormones (via bloodstream).

Pituitary gland

“master gland.”

Plasticity

ability to adapt after injury/experience.

Split brian

shows hemispheric specialization.

Genes

units of heredity.

Chromosomes

structures carrying genes.

Genotype

genetic makeup.

Phenotype

genetic makeup.

Dominant / recessive genes .

determine inheritance.

Monozygotic twins vs dizygotic twins

identical vs fraternal

Heritability

proportion of variation due to genes

Gene expression

when/if a gene is “turned on.”

EEG (electroencephalography)

brain waves.

MRI (Magnetic resonance imaging)

structure.

fMRI (functional magnetic resonance imaging)

activity (blood flow)

PET (Positron emission tomography)

metabolism (uses radioactive tracer).

TMS (Transcranial magnetic stimulation)

temporarily disrupts brain regions.

Consciousness

awareness of self and environment.

Attention

limited resource

Endogenous attention

intentional.

Exogenous attention

grabbed by environment.

Change blindness

failure to notice big changes.

Priming

exposure influences later behavior without awareness.

Subliminal perception

info processed below awareness.

​​Hypnosis

suggestibility, altered perception.

Meditation

focus, relaxation, altered awareness.

Drugs

psychoactive substances that change brain function.

Circadian rhythms

biological cycles (24h).

NREM

deep sleep.

REM sleep

dreaming, brain active, body paralyzed.

Activation synthesis hypothesis

brain tries to make sense of random neural firing.

Traumatic brain injury (TBI)

alters consciousness

Insomnia

trouble falling asleep

Narcolepsy

sudden sleep attacks.

Obstructive sleep apnea

breathing stops during sleep

Sensation

detecting raw info.

Perception

interpreting info.

Transduction .

converting energy → neural signals

Bottom up processing

data

Top down processing

expectation

Absolute threshold

minimum detectable stimulus.

Difference threshold .

smallest detectable difference

Signal detection theory (SDT)

detecting a stimulus depends on sensitivity + decision making.

Sensory adaptation

Reduced response after constant stimulation

Retina

photoreceptors

Rods

dim light, black & white

Cones

color, detail.

Fovea

sharpest vision.

Object constancy

perception remains stable despite changes

Binocular depth cues

need both eyes

Binocular disparity

slightly different images

Convergence

eyes turning inward.

Monocular depth cues

one eye (size, overlap, linear perspective).

Motion parallax

nearby objects move faster across retina.

How we hear

Sound wave → eardrum vibrates → inner ear → auditory nerve.

Temporal coding

low frequency.

Place coding

high frequency.

Taste buds

detect 5 tastes (sweet, salty, sour, bitter, umami).

Olfactory epithelium

receptors.

Olfactory bulb

processes smell (direct to brain, bypasses thalamus).

Haptic sense

touch.

Vestibular sense

balance (inner ear).

Pain

warning system for damage.