sensory perception Flashcards
visual sensory system: what does it contain? (5)
eyes (info enters, fires action potentials on rods and cones in retina) - brighter light, more AP
down optic nerve
to optic chiasma (where left and right optic nerves cross over)
enters lateral geniculate nucleus of thalamus
then goes back to primary visual cortex, complete vision is then assembled
what is the adelson checkerboard illusion
Using premises based on sensory evidence, perceived lighting conditions, and previous experiences, our visual system arrives at a false conclusion.
what is pareidolia
tendency to see patterns in things (thought og as psychosis but is normal, more pronounced in schizophrenia)
what is face pareidolia
tendency to see faces in things
what are the sensory systems for external stimuli - 6
somatosensory
visual system
auditory
vestibular
olfactory
gustatory
three types of somatosensory systems/ stimuli
tactile
proprioceptive
pain
what is the ascending sensory pathway (toe pain context) - 8
sensory stimulus (e.g. pain from stubbing toe)
action potential fired via sensory/ first order neuron
(in this case, up leg)
to spinal cord
carried onto second order neurons/ spinothalamic tract up spinal cord
then cross sides (e.g. if right toe, right first order neuron, then crosses to left spinothalamic tract, left part of spinal cord)
info goes into brain/ thalamus - relay centre, decides if info is important enough to enter third order neurons/ thalamocortical projections)
to cortex - where we make sense of it
what are first order/ sensory neurons
in processing of sensory info, these are the initial neurosn that carry info towards ns
found in eye, nose, etc
thalamocortical projections
third order neurons
spinothalamic tract
second order neurons
what are the general principles found in most sensory pathways - 5
specialised structures that transform sensory info into AP
AP travel to spinal cord
travel to spinothalamic tract
into thalamus for integration + filtering (except olfaction)
into cortex for interpretation + response
(problems in any stage can result in sensory disturbance)
decussation
“crossing over”
all sensory info we process decussates
all motor info sent down spinal cord decussates (left side of brain commands right foot)
unknown why rippp but only happens in vertebrates
stroke in left side of brain
affects right hand side of body!
what is the thalamus
sensory relay station
close to middle so basic ish
sensory filtering of info going into cortex (where is processed)
takes input/ feedback from limbic/ motox system and also from cortex
what is sensory gating
irrelevant sensory info can be filtered resulting in selective attention
what is the cocktail party effect
irrelevant info filtered - sensory gating
but able to respond to certain cues (e.g. going from a convo with someone to hearing ur name shouted at you from elsewhere)
rapid desensitisation to irrelevant interruptions
dec ability to do this in schizophrenia, may be improved by nicotine
what is the pulvinar nucleus of the thalamus
main structure responsible for sensory gating
sensory pathways - what happens when the AP enters the cortex in terms of parietal, temporal, and frontal cortex functions
parietal figures out where info is coming from (and orients it towards it)
temporal - what it is and where we have seen it before
frontal - what should we do about it/ not do about it - enables motor commands of what to do and shuts off what not to do
cortex vs lobe
cortex is outside layer
lobe is inside
(e.g. hippocampus is in temporal LOBE)
where is the fusiform face area
temporal cortex
on fusiform gyrus
what is prosopagnosia
where people cannot recognise others from faces aka face blindness
can recognise other features (hair colour, voice sound, etc), have other cognitive processes intact
no treatment
what causes prosopagnosia
some born with it as fusiform face area not developed, others post stroke symptom of that area - temporal lobe, fusiform gyrus, fusiform face area
what are super recognisers
opposite of prosopagnosia
often found in pts who had law enforcement role, don’t forget faces
4 regions of cerebral cortex + roles (in technical terms)
occipital - visual cortex
parietal - attend to stimuli
temporal - identifies nature of stimuli
frontal - selects and plans appropriate response
