Magnocellular and parvocellular pathway mediated luminance contrast discrimination in amblyopia

摘要: To evaluate whether luminance contrast discrimination losses in amblyopia on putative magnocellular (MC) and parvocellular (PC) pathway tasks reflect deficits at retinogeniculate or cortical sites. Fifteen amblyopes including six anisometropes, seven strabismics, two mixed 12 age-matched controls were investigated. Contrast was measured using established psychophysical procedures that differentiate MC PC processing. Data described with a model of the response primate retinal ganglion cells. All displayed same signatures tasks, three strabismics having reduced sensitivity. Amblyopic gain similar to electrophysiological estimates from visually normal, non-human primates. Sensitivity evident subset summation deficits, no change responses. The data do not support proposal amblyopic sensitivity but rather are due anomalous post-retinogeniculate processing signals.