Vision Physiology Flashcards
What must the photons be transduced into?
Electrical signals
What do the photoreceptors do?
Convert electromagnetic radiation to neural signals
What are the 4 main regions of the photoreceptors?
Outer segment
Inner segment
Cell body
Synaptic terminal
What does all-trans-Retinal lead to?
Closure of cGMP - gated Na+ channel, with lowered Na comes hyperpolarization
Is there more glutamate in the dark or in the light?
Dark
What is the receptive field?
Part of the retina that needs to be stimulated to elicit action potentials from a ganglion cell
When are Rods used more?
In dim light
When are cones used more?
In normal daylight
Where is the more convergence?
In rods, increasing sensitivity but decreasing acuity
Do ganglion cells cause changes in membrane potential or produce action potentials?
Produce action potentials
Where do horizontal cells receive input from?
Photoreceptors and project to other photoreceptors and bipolar cells
Where do Amacrine cells receive their input from?
Bipolar cells and project to ganglion cells, bipolar cells and other amacrine cells
The visual cortex is mapped out precisely, this is called what?
Visuotopic organization
What do the magnocellular LGN neurons protect?
Layer IVC alpha
What do the Parvocellular LGN neurons protect?
IVC beta
