Visual Area 4

Reasons for 'biopsy-only' for all patients were either location in eloquent areas: (motor area 18.7%, language area 25,3%, basal ganglia 7.7%, visual area 4.4%) or extension of the disease (corpus callosum invasion 14.3% and multicentricity/multifocality 28.6%).  

To determine the locus, full extent, and topographic organization of cortical connections of area V4 (visual area 4), we injected anterograde and retrograde tracers under electrophysiological guidance into 21 sites in 9 macaques.  

In Old World monkeys, the locations of visual area 4 (V4; ventral stream) and middle temporal area (MT; dorsal stream) projecting neurons in V2 supports the hypothesis that the cytochrome oxidase (CytOx)-rich thin stripes and the CytOx-poor interstripes are associated with the ventral stream, and that the CytOx-rich thick stripes belong to the dorsal stream.  

The modular organization of cortical pathways linking visual area 4 (V4) with occipital visual area 2 (V2) and inferotemporal posterior inferotemporal ventral area (PITv) was investigated through an analysis of the patterns of retrogradely labeled cell bodies after injections of tracers into V4 and PITv.  

Does the critical area involved in achromatopsia correspond to cortical area V4 of monkeys, often implicated in processing wavelength? When visual area 4 is totally ablated in monkeys they have only a mild colour discrimination impairment and easily solve the colour ordering and colour selection tasks that an achromatopsic patient finds impossible.  

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