Visual system Flashcards
Only retinal cells with voltage gated channels
= retinal ganglion cells- only cells that make APs
Horizontal cells
receive glutamatergic input from central photoreceptors and GABAergic from adjacent rods and cones, Gives ganglion cells concentric center surround
What are important for making the concentric center-surround field of retinal ganglion cells? What else do these cells do?
Horizontal cells
- impt for central surround
- impt for lateral inhibition= increased acuity
First cells to exhibit center-surround reception?
bipolar cells
The effect of light on a photoreceptor
hyperpolarization= decreased glutamate release.
Amacrine Cells
Modify input to M class ganglion cells. M cells are sensitive to moving stimuli.
Output cells of the retina
ganglion cells== form optic nerve
Magnocellular cells
motor, peripheral vision, most input is from rods. Some of these are the melanopsin cells
(also called Y or alpha cells)
Parvocellular cells
Most of the input is from cones (=color), central retina
= X cells or beta cells
Extra unnecessary names for primary visual cortex
V1, striate cortex, Area 17
Where do M and P cells diverge?
starting at area 18 V2 region
Temporal field goes to?
ipsilateral LGN
Nasal field goes to ?
contralateral LGN
Pupillary light reflex
Light–> retinal ganglion cells–> optic nerve–> optic tract–> LGN–> pretectal nucleus (post commissure connects both sides) –> accessory oculomotor nucleus–> (preganglionic symp fibers travel with CN III to) ciliary ganglion –> post ganglionic symp fibers to sphincter pupillae
Saccadic eye movement
Frontal eye field mediates this. Brodmann area 8. Stimulation (from lesion) causes eyes to look away.
Destruction causes eyes to look towards that side.
