PSYB51H3 Lecture Notes - Parallel Computing, Hemianopsia, Fusiform Face Area
Document Summary
Hemianopia: half of the visual field is missing [relative to your fovea] in both eyes or one eye. Optic chiasm is disrupted: crossing over of visual field info. is disrupted [so visual field info from left visual field eventually goes to the right hemisphere and vice versa. = this process is disrupted] = sorting of info occurs in the optic chiasm. [contrast sensitivity is a measure of the ability to discern between luminances of different levels in a static image. ] = lower spatial frequency means a lower contrast sensitivity. While contrast sensitivity rises at intermediate spatial frequencies & it comes to 0 at 60 cycles/degree [on graph] At 60 cycles/degree = can"t see anything anymore. In terms of neurons: higher spatial frequencies [60 degree/cycle] we can t simply resolve that b/c our photoreceptor fields aren t small enough and near 1 degree/cycle. There aren t enough neurons to represent these lower spatial frequencies.
