Achromatopsia is due to lesion in which area of occipital coex?
Correct Answer: Area v4
Description: Area v4 REF: Yanoff's ophthalmology p- 1300 Patients who have acquired, central cerebral achromatopsia (inability to identify colors) may have complete loss or miss only one primary color. The isolation of single color defects links with research performed in macaque monkeys, which showed that an area of prestriate coex, identified as area V4, contains neurons that respond to specific color stimuli. Patients with cerebral achromatopsia generally describe objects as "washed out" or "faded." Patients still may be able to use contrast clues to separate the edge of one intense color from another. If two colors or a color and a shade of gray match pseudoisochromatically, however, patients demonstrate a distinct inability to isolate colored targets. Despite the achromatopsia, other pas of the parvicellular system may remain intact. Patients may have normal visual acuity and contrast sensitivity. Postmoem and radiological studies of these patients reveal bilateral lesions of the inferior occipital coex.
Category:
Physiology
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