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active v. passive perception?: most is passive b/c cheaper and less dangerous, active is more powerful and less susceptible to changes in environmental conditions
external systems: long range (vision, audition), short range (gustation, olfaction, somatosensation)
internal systems: balance, proprioception (relation of organs)
aristotle: 5 sensations, perceive through heart b/c correlation btwn heart rate and sensation
descartes: everything is a reflex, seed of consciousness in brain
introspectionism: wilhelm wundt- 1879based on systematic observation-- observers catalogued elemntary mental states-- prob is language and consciousness
structuralist introspectionism: titchener--atoms of thought-- dies out by 1930s
psychophysics: seek exact quantitative relationships btwn physical parameters in outside world and qualities in mind of observer-- Gustav Theodor Fechner
methods of psychophysics: method of limits, method of adjustment, method of constant stimuli, magnitude estimation
method of limits: stimulus parameter presented in up or down order until subjects change answer and avg crossover valu = thershold. pros: quick, easy, need several trials, effective when approx response already known. cons: not very reliable, history dependent estimates(hysteresis), have to know approx range
method of adjustment: match test stimulus as close as poss to standard comparison stimulus-- pop in color psychophys or percep of space. pros: quickest & easiest, most fun. cons: most unreliable, set up biases ( motor interactions), requires trained observer
method of constant stimuli: stimuli presented in random order, samples more than parameter range to prevent hysteresis. pro: yields reliable theshold estimates, no hysteresis. cons: large # trials, under/oversampling stimulus ranges, fatigue & training effects
difference thresholds: compare stimulus against variable standard to find JND
webers laws: ratio btwn diff threshold and standard stimulus is usually constant-- t/s= constant (weber fraction)
manitude estimation: most percep doesnt occur at thresholds-- subject introduced to standard with magnitude and asked to rate test stimuli relative to standard
steven's power law: 2 si= <2 pi (response compression) 2si=2 pi (linearity) 2 si= >2 pi (response expansion)
signal detection theory: how to make optimal decisions under conditions of uncertainty- fire alarm example ( alarm and no alarm vs. faire and no fire)
SDT type 1 and type 2 errors: 1: claim theres an effect when there is none 2: don't see effect when there is one
cognition: our knowledge of world, mental reps of the world, and operations on those reps
basic, lower cog functions: perception, attention, memory, imagery (mem & image -> categorization)
higher cog functions: decision-making, reasoning/prob-solving
perception =?: all of lower & decision-making
saccadic eye mvmnts: 3 times per sec, brain shuts of incoming info
efference copy: percepual stability- ex. tickling
negative feedback: feel less than you exert, feel more when your the victim
emission theory of vision: empedocles- ray from eye to object, ray from object to eye - ACTIVE
intromission theory: lucretios- sun to object, object to eye
criterion for curves with sdt: want curves with large diff in mean and narrow variance
ROC curve: receiver operating characteristic- sensitivity of system- hits on y axis & false alarms on x axis
d': difference btwn means of probability distributions )signal v. noise)-- want d' to be as high as possible!
fmri: functional magnetic resonance imaging--measures bloodflow to an area: active neaurons take up oxygen, more oxygenated the more coherent the spins picked up by the magnet, compare activity to baseline
imagery debate: do mental reps of images retain the depictive properties of image itself or is it language? fMRI proved in image area, not language (kosslyn)
pros if neuroimaging: noninvasive, assess relatively complex behaviors, cheap & available at universities
cons of neuroimaging:: limited to structure & dynamics of vascoclature, temporal resolution limited to 1 sec, nonlinear relationship btwn blood flow and neaural activity, measures inputs to area, not outpts (dendritic activity, not action potentials), blood flow levels can change without corresponding changes in neural activity
parietal lobe, temporal lobe, cerebellum, occipital lobe, frontal lobe: spacial, auditory/memory, motor learning, visual, language
central sulcus: everything behind is perceptual, everything in front is motor
the neuron: dendrites squiggly attached to cell body w/ nucleus inside, axon hillock/spike initiation zone between cell body and axon (myelin long parts, nodes of ranvier short parts), then at the end is the synaptic cleft
resting membrane potential: resting membrane potential is when diff between outside (more +) and inside is -70 mV. this is created by imbalance of ions (na+, na-, k+). at rest, most k is inside and most na is outside and k can get through the k channel and the k wants to be as far apart as possible.
action potential: electricity flows, na flows into axon through na channel, depolarizes to -40 mv (threshold where na channels open) spurring action potential, and the voltage spikes to + 40 mv. at +40 mv, na + channels inactivate (abs. refractory period) and k is pushed out until back to -60 mv, except k is outside and na is inside. after AP, pumps back to rp conditions
absolute refractory period: +40 mV, na + channels inactivate, completely unresponsive to second stimulus
electrophysiology: put electrode next to neuron to pick up ion changing directly
3 interactions of wavelengths with matter: no interaction: transparent specular reflection: mirror, goes in straight, comes out straight, etc scattering: absorb some energy, change direction- normal object
lens- 2 types: converging & diverging
3 parts of eye that bend light: cornea (fixed lens that converges light), lens (if contracts, lens fatter, etc), vitreous body (gets dirty with age )
myopia/ hyperopia: eye too big, needs diverging lenses/ eye too short, need converging lenses
retina-- layers: transduces phys energy from light into electric signals-- gc, amacrine cell, bp, horizontal cell, pr, pe
rods: rhodopsin is pigment, can detect single photon, responsibe for scotopic (night) vision, bleached at high light levels, more numerous
cones: 3 classes using 3 diff photopigments, resp. for photopic vision, only active at high light levels, peak in fovea
optic nerve: blindspot where all ganglion cell axons exit eye
signal processing in retina: photoreceptors transduce light into electricity, then connected to bipolar cells, which are connected to each other by horizontal cells, and bipolar cells are connected to ganglion cells. information transfer from bp to gc is modulated by amacrine cells
convergence in retina: 125 mil receptors and 1 mil that send outputs-- degree of convergence diff for rods and cones
receptive field: part of visual field wherestimulus is effective in changing the electrical activity of a neuron
lateral inhibition -- in retina: neuron inhibits or suppresses its neighbors, for example a bright surface is represented by less spikes b/c it is redundant, so edges are more bright -- in retina, implemented by horizontal cells
parasol cell: retinal gang cells that recieve inputs from rods- are large & have large rfs
midget cells: retinal gang cells that recieve inputs from cones- are small and have small rfs
receptive fields of ganglion cells: have center and antagonistic surround- ON gang cells are activated by light in the center & suppresed by light in surround, OFF gang cells activated by light in the surround and suppresed int he center
suprachiasmatic nucleus: receives inputs from photosensitive gang cells, only few optic nerve fibers terminate here, regulates sleep- wake cycles according to the environment, sensitve to bright light for long periods of time-- causes insomnia in the blind
superior colliculus: some fibers of optic nerve terminate here, involved in control of saccadic eye mvmnts, could be involved in blindsight
thalamus: subcortical structure at center of brain- signals from all sensory organs except smell pass through, connected to all brain areas through thalamo-cortical loops
possible functions of thalamus?: could be relay responsible for filtering info, could be involved in consciousness, could reformat signals for cortex
lgn: nucleus in thalamus where visual info passes through- has 6 layers which each receives input from one eye so each side retains info from one visual hemifield-- ci? ic, ic.
lgn layers 1-2: magnocellular- receive inputs from parasol gang cells
layers 3-6: parvocellular- inputs from midget gang cells
v1 function: extract fund. features- orientation, ocular dominance, spatial freq, motion, depth, color
v1 rfs: larger than lgn's and elongated, inhibitory surrounds a form of lateral inhibition
orientation turning curve: neuron has preference for certain orientation
population tuning curve: 1 trial, many neurons, brain chooses for which neurons are most active
spatial frequency receptive field: if more lines fit into receptive field, higher freq
how is cortex organized?: hierarchical, computational columns-- each column does one feature, neighboring columns selective for similar features
cortical divergence: 1 mil retinal gang cells-> 100-200 mil v1 neurons
how is v1 organized?: retinotopically- if neighboring in vis field, neighboring in cortex and more cortical space in v1 allotted to rep signals from fovea
scotomas: specific legions in v1 cause complete loss of vis function in some regions of vis field
cortical blindness: complete loss of v1 function
2 streams of vision: dorsal (where?) vs ventral (what?)-- example of parallel, hierarchical processing in brain
ventral stream: v1-v2-v4-it/ffa
dorsal stream: v1-mt-fef/mst/lip
v2: precise function unknown, responds to illusory contouts
v4: responds to elementary shapes, curvature, geons
it: inferotemporal cortex- object perception
ffa: fusiform face area- face perception
mt: medial temporal area- responds to visual motion and computes object velocity
fef: frontal eye field- eye mvmnts, voluntary saccades & pursuit eye mvmnts
mst: medial superior temporal area- optic flow fields using focus of expansion
lip: lateral intra-parietal area- integration of motion percep/info over time and diff motion stimuli- decision making/categorization
what dimension lost in the retina?: distance
3 kinds of depth cues: oculomotor, monocular, binocular
oculomotor depth cues: work at short dist, accomodation (lens) and convergence (object far away, eyes forward, object close, eyes converge)
9 monocular depth cues: occlusion, shadows, relative height, spatial freq, texture gradient, linear perspective, atmospheric perspective, familiar size, motion parallax
miller- leier illusion: 2 lines that appear to be diff lengths cuz of arrows on ends
stereopsis: binocular vision
binocular disparity: calculate diff btwn 2 eyes to calculate depth-- disparity btwn positions of 2 image pts on retina
objects that fall on the horopter..: fall on corresponding pts on retinae and have 0 disparity
objects that fall off the horopter....: fall on noncorresponding pts on retina: farther away= uncrossed and closer= crossed
absolute disparity: angle btwn actual pt and corresponding pt- indicates how far from the horopter
relative disparity: diff btwn absolute disparities of 2 objects- indicates how far they are from each other
pulfrich effect: pendulum circles around, not side to side
the correspondence problem: to compute depth, all dots in one image must be matched up with dots in other image
motion parallax: close object moves opposite, far object moves same
where are neurons sensitive to absolute disparity and relative disparity found?: absolute found in early visual cortical areas/dorsal stream and relative in later areas/ ventral stream
motion-- fundamental or derived?: seperate perceptual dimension- present in most animals
evidence for motion as seperate perceptual dimension: motion after-effect, apparent motion (tv),induced motion (illusions)
reichardt detectors: in vi- integrate illuminance signals from lgn- direction and speed selective
motion rf orientation: orietned in space time (x=space, y=time), sensitive for direction and speed
motion camoflage: keep angle constant
aperture problem: if end of line not in sight, you can only see component perp. to orientation of line
IOC- intersection of constraints: velocity found by connecting origin of velocity-space to intersection of constraint lines--computes global motion/veridical object velocity
area STPa: biological motion--ex point light walker
most common color blindness--3 kinds: dichromats: protanopia AAO deuteranopia AOA tritanopia0AA
trichromatic theory of color: aka young-helmholtz theory--color is relative activity of 3 cone photoreceptors as activated by diff wavelengths, evidence is color deficiencies and color matching experiments--true in retina
metamers: physically diff, perceptually same
opponent process theory: evidence is color mixtures, afterimages, color contrasts-- colors oppose each other-- true in LGN
additive vs subtractive color mixing: additive- lights, add energy at diff wavelengths subtractive- paints, subtract energy
color-brightness constancy: illuminance biases amnt of wavelength reflected-- various processes involved
color in the cortex: color responsive neurons found in many vis. areas in ventral stream-- distributed process
adams surrounds: lined colored squares, one is attractive shift, one repulsive
object perception & memory: memory next door, once object identified, ou know more about it then you see and youll rememebr it forever
inverse projection problem: image on retina is ambiguous, could have been created by diff objects, infinite # soluions and brain must pick one
viewpoint invariance: can see same objects at diff perspectives
problems with object recognition: ambiguity, viewpoint, occlusion/incompleteness, image quality, lighting, unfamiliarity
psych functions underlying object perception: percep. segregation, percep grouping/organization, linecontinuation/ completion
principles of percep segregation: figure/ground--symmetry, smaller area, meaning, motion imply figure
percep grouping: see things easiest/ likeliest-- gestalt!
structuralism: old and wrong percep grouping belief-- se little specks and put them all together
gestalt-- 8 principles: whole more than the sum of its parts- pragnanz (least assumptions), similarity, good continuation, connectedness, proximity, common fate, meaningfulness/familiarity, synchrony
line continuation: tendency to interpret lines as continuous- smoothest interpretation favored
geons: recognized by v4- non-accidental, invariant features- straight edges, collinearity, t-junctions, etc
lesions in area it create.?: visual agnosias, probs with viewpt invariance and object segmentation
neural responses in area it: very specific to object, invariant to color orientation size texture
binocular rivalry: if you see diff stimuli in 2 eyes then brain represses 1
3 possibilities for how objects represented in area it: grandmother neurons- one neuron, one stmulus, logical conclusion of hierarchical model but doubted population code- decode peak along linear stimulus dimension- conventional barcode- key combo of activities, if true then were out of luck
plasticity & 3 time scales: central to cog function, think hapens on level of indiv neurons-- ontogenetic (dev), short term ( percep learning), ultra short term (attention, adaptaton)
unilateral parietal lesion: hemi-neglect- breakdown in spatial attention ( draw half a clock)
attention & 2 models: results from narrowing cortical architecture of less & less independent info channels (bottleneck)-- biased competition and feature similarity gain
biased competition: neuronal pool with diff tuning prefs inhibit each other and compete for higher firing rate, one has head start b/c attention
feature similarity gain: no change in fund tuning props or prefs, attention changes gain of pool-- attention and phys characteristics direct tradeoff-- evidence supports!
decision making in vis cortex: once neurons in lip reach certain threshhold, decision made
cortex columnar structure: neurons organized in cortical columns w/ similar prefs grouped together, columns compete, neural voting isnot equal but weighted by reliability
corollary discharge theory: prob- motion could be self or other generated, so motor areas send efference copies to percep areas
ebbinghaus illusion: brain takes context into account, but motor areas make up for it
time perception: might not be percep b/c no transformation of energy involved, could be what brain does anyway, interpreted.. not simple readout from pacemaker
4 modes of temporal cognition: simultaniety, temporal order, subjective present, duration
subjective present: 3 seconds, evidence, necker cube changes every 3 secs, seach though in speech should be 3 secs, like saddle in time, 'indifference interval'- at 3 secs your subjective estimate of time matches objective experience
duration percep: prone to ext & int influences, changes with diff time scales, practice effects
physiological clock hypthesis: chemical? pacemaker of some sort, ev. temp (fever, ppl count faster), fatigue (when tired, count longer), drugs (anesthesia shortens time, drugs lenthen it)
cognitive clock: 60s and 70s-- percep is interpretation of dynamics of mental content going on anyways, more like byproduct
time percep as change percep: if more events occur, interval judged as longer, if even is novel, interval judged as longer, if events are complex, interval judged as longer --distinguishes empty from filled
attention effects on time percep: if paying attention to passage of time, time lengthens dramatically
memory effects on time percep: in hindsight, filled intervals appear longer and empty intervals shorten
emotions effects on time percep: pain & fear drastically lengthen time, positive emotions shorten it
age & passage of time: passage of time accelerates with age-- gives rise to logtime hypothesis-- new time interval judged relative to time passed thus far, ex. 1 yr old, next year is 100% time already spent-- bad implications for subjective life expectancy!
alternate explanantions for slowing time passage with age: limited space for memory representatons, slowing metablism, lodified log hypothesis
possibilites for physiological/neuronal time percep: completely distributed (neuronal fires, refractory periods, etc), suprachiasmatic nucleus, cerebellum (process reg, precise, short timesclases like motor actions), parietal lobe (moderate timescales, gauge elasped time)
function of temporal cognition on short and long time scales: short- organize behavior as coherent goal-directed set long- organize behavior in terms of behavioral economics
the auditory system & stimulus: long-range, external, stimulus is pressure waves in air(20-20000 Hz in humans)
pure tone: sounds represented by a sine wave
frequency: 1/wavelength-- higher freq= higher pitch
amplitude: corresponds to sound pressure, measured in decibel
loudness: function of bouth frequency and amplitude
where is our hearing most sensitive?: 300-5000 hz- conversational speech
complex sounds: many diff freq present at once, most sounds, additive synthesis (pressure waves add)
music notes: fundamental freqs added with other tones-- harmonics
fourier frequency spectrum: simple sine wave components of soundwave
timbre: produced by harmonics
frequency in vis and auditory systems: vis: hue, color aud: pitch
amplitude in vis and auditory sstems: vis: luminance aud: loudness
white light and white noise: contain all frequencies
outer ear: acts as funnel to direct sound waves towards inner structures- filled with air
middle ear: 3 small bones (ossicles) that amplify sounds--filed with air
inner ear: contains structures that transduce sounds-- filled with liquid
sound waves in middle-> inner ear: make eardrum vibrate, hammer/anvil/stirrup take mass of vibrations and transfer to oval window for amplification
pinna: like funnel
ossicles: equalizer system-- amplify specific freq more thanothers (ex. conversation)-- startwearing out with age
organ of corti: contains transducers to transduce mech. pressure waves into action potentials--contains basilar and tectorial membranes and hair cells, hair cells cilia move against tectorial
cochlea: tonotopically organized--freqs map onrderly on length
basilar membrane: has hair cells, death starts near beginning closer to oval window,pattern of vibration of hair cells depends on freq of sound wave
place code: pattern of vibration of hair cells depends on freq of sound wave-- high freq near oval window,, low freq near apex, stiffer at base and looser at apex
place theory: each freq causes maximum displacement of basilar membrane at diff position
mechanical gating: vibrations mechanically open channels of cilia, changing voltage inside cell--vibes pull open ion channels, ions flow in, voltage potential changed in cell, changes amnt of neurotransmitter released into synapseof neuron in auditory nerve
auditory pathway to cortex: ear, auditory nerve, cochlear nucleus (brain stem), superior olivarynuclei (sound localization, crossing over info from both ears in both hemispheres), inferior colliculus (reorients attention to sound), medial geniculate nucleus, primary auditory cortex (a1, temporal lobe)
3 parts of auditory cortex: core are ( pure tones) belt area (higher order sounds, lyrics, speech) primary auditory cortex (organized tonotopically, speech freq overrepresented
auditory adaptation: cells in cortex have characteristic freq, prolonged exposure to tone of cf raises threshold of neuron -- why stop hearing ambient noise
localizing sound sources- where stream: 3 ways- interaural time diff, interaural level diff, spectral cues
interaural time difference: encode sound sources-- diff in time it takes for sound waves from single source to reach r and l ear, neurons in superior olivary respond to itds, work like reichardt detectors
interaural level difference: encode sound localization-- diff in spl at each ear, ear away casts acoustic shadow, slightly quieter. mostly for high freq sounds
spectral cues: encode sound localization-- monaural, head related transfer function, ear amplifies some freqs and attenuates others, effect depends of vertical position of sound source to head
identifying sound sources: cochlea responds to simultaneous sounds from mult sources undifferentiated, stimuli must be grouped to be identified
shepards tones: in octave relationship to each other, always in equal loudness
major diff btwn vision and audition: temporal fidelity in audition better than vision b/c vision is chemical transduction, not mechanical
mcgurk effect: auditory ba, visual ga, brain guesses da
sound induced rabbot effect: think as many rabbits as there are sounds
motions bounce illusion: sound makes it unambiguous
somatosensation: subcortical processing-- cutaneous senses (touch, temp, pain), proprioception (acceleration/body orientation), kinesthesis (position/mvmnt of limbs), introception (thirst, satiety, nausea, bladder, etc)
skin: 'retina' of cutaneous senses b/c transducers, 3 layers - epidermis, dermis, subcutaneous)
4 touch receptor types: merkel receptor/merkel disk, ruffini cylinder/ ending, meisner corpuscle "stack", pacinian corpuscle "onion"
merkel receptor: touch receptor-- shallow, small rf, slow adapting, respond to slow pushing and fine details
ruffini cylinder: touch receptor-- deep, large rf, slow adapting, respond to sloow stretching
meisner corpuscle: touch receptor-- "stack", shallow, small rf, rapid adapting, responds to light tapping, flutter, gripping things
pacinian corpuscle: touch receptor-- "onion", deep, large rf, rapid adapting, respond to vibration, texture from motion
2 pt threshold: used to elicit absolute sensitivity of diff regions of skin to infer spacing/size of rfs, thresh lowest on face and hands, hairy skin less sensitive than hairless skin
2 ascending pathways for touch: - touch fibers enter spinal cord in dorsal root, some fibers synaps onto local interneaurons which synapse onto motor neurons (spinal reflex arc) -travel up to brain carrying info to brain stem, travels in medial lemniscal pathway, synapses in brainstem and cross to opposite side of brain, synapse in thalamus and neurons project to cortical areas
thermoreceptors: free nerve endings, cold fibers react to decrease in temp(20-45 c) and warm fibers react to increase (30-48 c), indiv fiber has preferred temp
spinothalamic tract: in spinal cord- conveys temp and pain related signals to brain
somatosensory cortex: s1 & s2-- immediately poterior to central sulcus, full sensory map of body, organized somatotopically (size scaled with amnt of sensory input)
use dependent cortical magnification: more you use things, more area they get
focal hand dystonia: musicians--crippling pain in hnds from overuse and repetition, therapy by immobilizing all fingers but one, get back one at a time
phantom limb pain: more than half of amputees, usually when amputated later in life, prob sprouting with representations of other regions invading lost limb area
insular cortex: homeostasis, thirst hunger nausea, emotions, seems to represent trust (link btwn physical and interpersonal warmth)
3 kinds of pain: neuropathic-results from damage to neural system itself nociceptive- activation of receptors (nociceptors) in skin inflammatory- due to tissue damage, release chemicals that activate nociceptors
visceral pain: organs that are in contact with outside wold have inflammatory pain (digestive system)
nociceptors: pain receptors- specialized for diff stimuli, free nerve endings connected to various fibers
A8 free nerve endings, C free nerve endings: a8- small, myelinated, high conductance speed, sensitive to mechanical noxious stimuli c- small, unmyelinated, slow conductance, sensitive to noxious stimuli
cortical pain processing: many regions involved, sensory aspects in somatosensory cortex, emotional distress processed in anterior cingulate cortex (active in sadness, unpleasantness, pain, social pain)
3 types of pain control: peripheral- gate control theory, pain intensity top down influenced by many factors central- endogenous opiates and corresponding receptors in brain conscious- pain control through neurofeedback (fire)
chemical senses: olfaction and gustation, short range, most ancient system available to organisms, detects presence of certain molecules in environment
macrosomatic/ microsomatic animals: macro- high reliance on olfaction micro- low reliance on olfaction
smell prism: (from top to bottom, l to r) flowers, spicy, fruity, resinous, putrid, burned
olfactory system: olfactory mucosa->olfactory bulb->pyriform cortex, orbitofrontal cortex, amygdala NO THALAMUS
entosomatic state: cribriform plate cuts receptor cells and cant smell, often leads to depression b/c smell stimulates brain
nasal passage: -> olfactory receptor cells, go through cribriform plate holes to olfactory bulb
olfactory receptor neurons: analogous to rods/cones, mouse has more types than we do (350 for humans), 10,000 of each type, membrane bound proteins located in cilia on top of ORN causes change of membrane potential
odor perception in relation to phys/chem properties: similar molecular structure doesnt lead to similar perception, combinational
olfactory bulb organization: 4 zones, contains glomenulus (primary structure in bulb, receives input from 5000-10000 ORN, input is chemotopic) and mitral cells which fire action potentials-- ipsilateral (no crossing over)
neurons in olfactory bulb: many respond to variety of odorants, many multimodal, affected by behavioral/emotional context
pheremones: chemicals that elicit behavioral response, animals have accessory olfactory system (vomeronasal organ), evidence for human pheremones in syncing of periods
major histocompatibility complex: females prefer odors from males with allelic matches to paternally inherited MHC genes
taste vs flavor: taste is gustatory system, flavor is taste and olfaction
tongue: gustation organ, not dedicated cuz also somatosensory, covered with papillae
papillae & 4 types: about 6 taste buds in each-- filiform (conical, entire surface, not involved in taste), fungiform (mushroom, tip &sides), foliate (folds along sides), circumvaliate (flat mounds, back)
taste buds: 6 in each papillae, also in roof of mouth and gut, sweet salty sour bitter umami (all over tongue,not specific places)
gut taste receptors: carbs, fat, protein, etc b/c tongue taste receptors too small to fit
gustation pathway: 3 facial nerves->NST->thalamus->insula or frontal operculum
flavor perception: oral &nasal cavities linked in nasal pharynx, thing on tongue evaporates to nasal covity, phys processes operating outside percep pathways have influence on flavor

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