Lecture 11 - Vision Flashcards
from which range of wavelengths of light is the visual system sensitive to?
380-740nm
which pathway in the brain is for spatial location (where)?
dorsal
which pathway in the brain is for object identification (what)?
ventral
how many cell types in the retina, how many nuclear layers and how many synaptic layers?
7, 3, 2
name the 3 nuclear layers of the retina
outer nuclear layer, inner nuclear layer and ganglion cell layer
name the types of cells found in the retinal outer nuclear layer
photoreceptors - rods and cones
name the types of cells found in the retinal inner nuclear layer
horizontal, bipolar and amacrine cells
name the type of glial cell found in the retina
muller cell
name the 2 synaptic layers of the retina
outer plexiform and inner plexiform
in the outer plexiform synaptic latyer of the retina there are synaptic connections between which 3 types of cells?
photoreceptors, horizontal and bipolar cells
in the iner plexiform synaptic layer of the retina there are synaptic connections between which 3 types of cells?
bipolar, amacrine and ganglion cells
order the layers of the retina from outermost to innermost: outer nuclear, inner nuclear, ganglion, outer plexiform, inner plexiform
outermost: outer nuclear, outer plexiform, inner nuclear, inner plexiform, ganglion : innermost
which type of cells span the entire thickness of the retina?
muller cells
in which synaptic layer of the retina are there on and off connections?
inner plexiform
name the range of light level in log cd/m2 that rods allow us to see light in
-6 to 1
name the range of light level in log cd/m2 that cones allow us to see light in
-3 to 10
the range of light in which rods are active is known as what?
scotopic range
the range of light in which cones are active is known as what?
photopic
the range of light in which cones and rod activity overlaps is known as what?
mesopic range
in which segments of rods/cones does phototransduction occur in? what is also contained within these segments?
outer segments, opsins
which photoreceptor is responsible for vision in dim light (darkness, moonlight, candlelight)?
rods
which photoreceptor is responsible for vision in daylight/ bright sun/starlight?
cones
which photoreceptors have high spatial acuity/high resolution images, low sensitivity and a narrow angle of coverage? what type of vision is this?
cones, central vision
which type of photoreceptors have low resolution images/poor spatial acuity, high sensitivity and aids in motion detection? what type of vision is this?
rods, peripheral vision.
short wavelength cones detect which colour of light?
long wavelength?
medium wavelength?
short - blue
long - red
medium - green
photoreceptors trigger which two types of cell which creates a glutamatergic response?
bipolar and horizontal
what sort of size receptive field does the fovea have? what about the periphery?
fovea is small, periphery large
midget (p) cells are the basis for the what pathway and they recognise which two things?
form and colour
parasol cells (m) detect which 2 things and are part of which pathway?
motion and distance, dorsal
in which location in the brain does the division between the dorsal and ventral pathway become anatomically evident?
lateral geniculate nucleus of the thalamus
S cones connect to S-cone biplar cells - which colour is this detecting?
what about L and M cones - what colour?
S = blue
L+M = yellow
in a B/Y bistratified ganglion cell where does the excitatory input come from? where does the inhibitory input come from?
excitatory from S cone bipolar cells
inhibitory from L+M cone bipolars
what does the superior colliculus in the retinotectal tract aid?
eye movements
what does the pretectum aid reflexes of?
pupil
in the retinohypothalamic tract what is the hypothalamus responsible for?
circadian rhythms
the left visual field falls on which nasal retina?
left
what is the name of the location at which optic nerves from both eyes meet?
optic chiasm
at the lateral geniculate nucleus how many layers in total? how many are parvo pathways at the top? how many are magno pathways at the bottom?
6 layers, top 4 are Parvo pathways, bottom 2 are Magno on each eye
in the lateral geniculate nuclei for both eyes, give the pattern of contralateral and ipsilateral layers starting from 6 going down to 1
c, i, c, i, i, c
to which cortex do LGN neurons project to
striate/6th
what is the name of the band of myelinated axons runnning parallel to the surface of the cortex along the calcarine fissure of the occipital lobe?
stria of gennari
main input from LGN is to which layer?
4
in which layer of the striate cortex are cells monocular? what are they in the other layers?
layer 4, binocular
what is the name of columns in which the striate cortex is organised? do they alternate between left and right eye?
ocular dominance columns, yes
for which type of cells (simple or complex) is the hubel and wiesel model for?
simple
which 2 types of cells in V1 receptive fields perform length summation?
complex and simple
which type of cells in V1 receptive field have inhibitory flanks on the ends of the receptive field?
hypercomplex
which type of cells in V1 receptive field have separate on and off subregions?
simple
which type of cells in V1 receptive fields are line detectors?
simple
which type of cells in V1 receptive fields are motion detectors?
complex
which type of cells in V1 receptive fields are angle detectors?
hypercomplex
which 3 types of cell can work together to decompose the outlines of a visual image into short segments
forming the basis of simple and complex
object recognition?
simple, complex and hypercomplex
