Lecture 1 Flashcards
what are the three stimuli the visual system needs to recognise
food
predator
mate
the right hemifield activates the
left part of the brain
what part of the brain processes visual info
lateral geniculate nucleus
what are the two main pathways in the visual system
dorsal - where - posterior parietal
ventral - what - inferior temporal
OFF cells express
inotropic glutamate receptors
ON cells express
metabotropic glutamate receptors
describe taste transduction
the taste buds detect stimulus - pass it on to solitary nucleus of brainstem - goes to ventral posterior medial nucleus - goes to insult and parietal cortex
why is sound important
communication emotion recognition different sounds topographic view auditory survival
what features of sound need encoding
frequency
intensity
onset
duration - ear has to remain sensitive without fatigue
what is the human equivalent of the mushroom body
piniform complex
what is the human equivalent of the lateral horn
amygdala
what is the amygdala for
innate behaviour
chambers of cochlea
scala vestiboli - top
scala media - middle with organ of corti
scata tympani - bottom
what is in the Scala vestibule and the Scala tympani
perilymph
low potassium
normal calcium
what is in the scala media
endolymph
high potassium
low calcium
wheat is the organ of corti
tectorial membrane
at rest what is happening on the general hair cell
slight tension at tip links
resting MET current
large electrical gradient for potassium entry
what happens during excitation
large deflection of hair bundle maximal tip link tension large MET current fully depolarises hair cell (-30mV) rapid train of action potentials
what happens during inhibition
large deflection of hair bundle in opposite direction
minimal tip link tension
no MET current
fully HYPERpolarises hair cell below resting potential (-65mV)
no or very few action potentials
outer hair cells
V shaped hair bundle
majority of nerve are efferent fibres
prestin
function is to amplify the cochlea
where do the type I afferent neurones go
IHC (95% of all afferents)
type II afferent go
OHC (5%)
LOC efferent
to IHC
MOC efferent
OHC
what is the lateral geniculate nucleus
6 layers macular input (1 eye) layers alternate input from each eye organised retinotopically located deep so not much known
what is the thralamic relay station
ganglion axons make 1:1 connections with LGN
do the ventral and dorsal pathways interact
yes
as the hierarchical model of object recognition goes down
decreases in stimulus complexity
where are the simple cells located
layers 4+6 responds to bar in certain orientations presented in centre of receptive field
where are complex cells located
layers 2,3+5 responds to bar in certain orientations anywhere in the receptive field
what are the receptive fields downstream of V1
increase in complexity
receptive fields increase in size
