AP PSYC UNIT 1B

circadian rhythm

an organism’s 24 hr “internal clock” cycle of physical, mental, and behavioral changes

melatonin

the key sleep hormone released and suppressed at certain times during our circadian rhythm

sleep cycle stage 1: N1

transition stage

• theta waves

• hypnagogic sensations (vivid, dream-like sensations during the transition from wakefulness to sleep)

sleep cycle stage 2: N2

light sleep

• sleep spindles (bursts of brainwave activity connected to memory consolidation)

sleep cycle stage 3: N3

deep sleep

• delta waves (slow/large brainwaves)

• decreased heart rate and blood pressure

• physical development + strengthening of the immune system

sleep stage 4: REM

REM sleep

• paradoxical stage (brain produces waves similar to wakefulness, but body is paralyzed neck down)

• dreams

• length of REM increases as night progresses

REM rebound

increased amount of REM needed when sleep deprived

leptin

the hormone responsible for metabolism and hunger

• when sleep deprived, decreased hormone levels (leads to increased hunger)

EEG (electroencephalogram) 

recording of how stimuli affect neural brain activity

sleep deprivation

• fatigue

• cognitive decline (poor memory and concentration)

• depressed immune system

• emotional irritability (disconnect between amygdala and prefrontal cortex)

• decreased leptin hormone (increase hunger)

hypnagogic sensations

vivid, dream-like sensations during the transition from wakefulness to sleep

activation synthesis theory

sleep is the brain’s attempt to make sense of random neural activity in the brain stem during REM sleep

memory consolidation theory

sleep is useful for organizing memories and making short term —> long term memories

insomnia

difficulty falling or remaining asleep and persistent reawakening

• treated w/ sedatives or sleep restrictions 

narcolepsy

sudden and irresistible onsets of sleep during normal waking periods

• wakefulness —> REM (lasts 10-20 mins)

• treated w/ amphetamines

REM sleep behavior disorder

moving or acting out dreams during REM sleep

sleep apnea

frequent and temporary halt of breathing for 15-60 secs during sleep

• treated w/ CPAP machine

somnambulism

sleepwalking during stage 3 (deep sleep)

absolute threshold

the lowest possible level of a stimulus that a person can detect (at least 50% of the time) 

just noticeable difference (difference threshold)

the minimum difference a person can detect between 2 stimuli

weber’s law

just noticeable difference is proportional to the intensity of the original stimulus (ex. WILL notice a change in sound in a quiet room but WONT in an already loud room)

signal-detection theory 

our ability to detect a stimulus depends on the strength of the stimulus and our psychological awareness

transduction

the process of converting a physical stimulus into a neuro-chemichal message sent to the brain

sensory interaction

McGurk affect - our vision can overpower most senses (ex hearing)

sensory adaptation

when we are exposed o stimulus for long enough, our receptors decrease their sensitivity to make them less noticeable

synesthesia

abnormal blending of the senses in which the stimulation of one sense produces sensation in other senses

retina

lining at the back of the surface of the eye

• where transduction occurs

• contains photo receptors to process light info

blind spot

part of retina with no photo receptor cells, where eye connects to the optic nerve

visual nerve

optic nerve

accommodation

curvature of lens adjusts to focus light and create a sharp image

rods

• blurry, shapes, movement

• low light

• black and white 

cones

• sharp, detail

• high light

• colorful

trichromatic theory

process color by combining 3 types of signals

• blue(short)

• green(medium)

• red(long)

opponent-process theory

ganglion cells process colors in pairs —> red-green, blue-yellow, black-white

—> explains after image effect with american flag

fovea

greatest point of visual activity on retina —> highest concentration of cone photo receptor cells

ganglion cells

next layer of cells that transfer messages from bipolar —> optic nerve

color blindness

dichromatism: see 2/3 primary colors

monochromatism: see 1/3 colors (red, green, blue)

Prosopagnosia

face blindness

blind-sight

damage to visual cortex causes blindness, but patients are able to subconsciously respond to visual stimuli

pitch

determined by the frequency/length

• ex: short waves = higher pitch (and frequency) 

loudness

determined by amplitude and frequency

place theory

different wavelengths trigger different “places” on basilar membrane

volley theory

group of neurons “take turns” firing rapidly, creating a volley to represent the highest-pitch sounds

frequency theory

the whole basilar membrane vibrates and brain measures intensity/frequency  of neural impulses raveling up auditory nerve (explains low pitch)

sound localization 

ability to perceive the location by processing differences in timing and intensity of sound waves

basilar membrane

hair cells bend on membrane as it ripples, triggering transduction, converting mechanical vibrations into neural impulses

conduction deafness

damage/blockage in the middle ear

sensorineural deafness

damage to the cochlea’s hair cells in the inner ear

vestibular sense

balance

kinesthetic sense

body position and movement awareness

gate control theory

perception of pain: the spinal cord contains a gate that blocks pain signals or allows them to pass on to the brain

• closed by stimuli (rubbing a wound)

frontal lobe and prefrontal cortex

FL: problem solving, judgment, speaking

PFC: emotional traits, decision making, judgment

heritability

percent of variation among individuals in a group due to genes (not individuals)

contralateral functions

LEFT hemisphere (right visual field): language, speech, logical reasoning

• can create explanations SO PPL COULD SAY WHAT SAW

RIGHT hemisphere (left visual field): spacial reasoning, perceptual awareness

• COULD ONLY DRAW NOT SPEAK WHAT SAW

hypothalamus (hype to eat)

maintenance functions (homeostatic state)

thalamus (muscles control sensations)

sensory control center (directs and transmits sensory info)

temporal lobe (tempo)

auditory info processing, understanding language, hearing

occipital lobe (optic)

visual info

threshold

minimum stimulation needed to trigger a response