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Spectral sensitivity in hemianopic macaque monkeys
Author(s) -
Cowey Alan,
Stoerig Petra
Publication year - 1999
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.1999.00635.x
Subject(s) - photopic vision , scotopic vision , mesopic vision , blindsight , macaque , striate cortex , sensitivity (control systems) , adaptation (eye) , spectral sensitivity , psychology , optics , audiology , neuroscience , visual cortex , physics , wavelength , medicine , retina , visual perception , electronic engineering , engineering , perception
We measured the increment threshold sensitivity to 2°, 200‐ms targets presented at a lateral and radial eccentricity of ≈ 20–26° in both visual hemifields of three macaque monkeys whose left striate cortex had been removed 5 years earlier, and in one normal control. As in patients with blindsight, sensitivity of the hemianopic field for blue, green and red stimuli was reduced by as little as 0.5 log units. With increasing light adaptation from scotopic to mesopic to photopic levels, there was a progressive increase in the sensitivity to long wavelengths relative to that for short and medium wavelengths. This shift in relative sensitivity (‘Purkinje shift’) shows that rod and cone mechanisms operate in both the normal and hemianopic fields and that the sensitivity that remains following removal of striate cortex is not mediated exclusively by rods.