Lecture 10: Vision ll, Touch, and Taste Flashcards
what type of cell is located at the furthest back point in the eye?
photoreceptors
photoreceptors’ leak sodium channels are always ____ in the dark
depolarized
how are ON and OFF bipolar cells differentiated?
by whether they inhibit or exhibit glutamate
what is the effect of light on photoreceptors?
they are hyperpolarized and stop releasing neurotransmitters
function of retinal ganglion cells
integrate information from ON and OFF bipolar cells
how are the receptive fields of ganglion cells organized?
“center-surround” organization
how are retinal ganglion cells classified
they are called ON or OFF cells, depending on whether they show increased or decreased spiking activity when light is presented in the center of their receptive field.
ON retinal ganglion cells
excited by the light in the centre and are inhibited by light in the surround
OFF retinal ganglion cells
excited by the light in the surround and are inhibited by light in the centre
function of retinal ganglion cells in the fovea
process colour information
types of receptive fields of retinal ganglion cells
Yellow on, blue off
Blue on, yellow off
Red on, green off
Green on, red off
in a yellow on, blue off receptive field
yellow is at the centre and blue makes up the border
in a blue on, yellow off receptive field
blue is at the centre and yellow makes up the border
where does visual information go after retinal ganglion cells?
Visual information is relayed from the retinal ganglion cells to the thalamus (the lateral geniculate nucleus) to the area V1 in the cerebral cortex (primary visual cortex)
receptive fields of V1 neurons
the sum of many RGCs
simple cells in the primary visual cortex
sensitive to lines of light and their receptive fields are typically organized in a center-surround fashion
difference between neurons in the V1 and retinal ganglion cells
Neurons in the V1 have larger receptive fields than retinal ganglion cells
v1
another word for primary visual cortex
when are neurons in V1 most active?
when a line of light in a particular orientation is detected in the receptive field
what do V1 neurons try to determine?
borders, edges, and corners
how much of the cerebral cortex is dedicated to processing visual information?
20-25%
visual association cortex
part of the occipital lobe that surrounds the primary lobe
t or f: Visual processing extends into the temporal and parietal lobe
true
dorsal stream
encodes where objects are. Starts in the primary visual cortex and ends in the posterior parietal cortex.