VISION3 Flashcards
in the retina, the image is
inverted top to bottom and left to right
ephs
ephrin B2 is at optic chiasm and neurons that express eph1 cannot cross over
mononuclear blindness
disease or damage of one of the eyeballs or of the optic nerve that results in loss of vision int he affected eye and loss of respective visual field
anopsia
relatively large visual field deficits
bitemporal hemianopsia
loss of information frm the nasal retina
can result from compression of the optic chiasm (pituitary tumor or aneurysm of circle of willis)
homonomous hemianopsia
loss of vision in half of the visual field where the same portion of the visual field in each eye is lost
produced by any lesion more central than the optic chiasm
3 groups of cells
simple cells
complex cells
hypercomplex cells
simple cortical cells
several on center ganglion cells in a row
rectangular receptive field–grid of rteina- depends on orientation of stimulus in that small piece of retina
complex cortical cells
larger receptive fields
ona nd off responses throughout
sensitive to rientation and length
best input is end of a line of that orientation
two simple cortical cells synapse on
an end stopped complex cell
hypercomplex
only a stimulus of correct shape and orientation moving in a proper direction will excite the cell1`q
as you go higher in the visual system
there appears to be a greater degree of convergence of visua information
orientation columns
cells arranged in vertical columns, so that if you go down through a column all of the cells will have the same orientation specificity
hyper column
two ocular dominance columsnt together (right and left)
an ocular dominance column are vertical columns with cells receiving input from same piece of retina
BLOBS
groups of cells that process color information and do not have orientation specificity
-interspersed among the columns
critical period to avoid cortical blindness
0/6years
strabismus
misalignment of two eyes
- -usually due to improper control of gaze by eye muscles or due to weakness or damage to one of muscles
- -results in lack of coordination between eyes