Cortical Connections of Area V4 in the Macaque

Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892-1366, USA.
Cerebral Cortex (Impact Factor: 8.67). 04/2008; 18(3):477-99. DOI: 10.1093/cercor/bhm061
Source: PubMed


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. Injection sites included representations ranging from central to far peripheral eccentricities in the upper and lower fields. Our results indicated that all parts of V4 are connected with occipital areas V2 (visual area 2), V3 (visual area 3), and V3A (visual complex V3, part A), superior temporal areas V4t (V4 transition zone), MT (medial temporal area), and FST (fundus of the superior temporal sulcus [STS] area), inferior temporal areas TEO (cytoarchitectonic area TEO in posterior inferior temporal cortex) and TE (cytoarchitectonic area TE in anterior temporal cortex), and the frontal eye field (FEF). By contrast, mainly peripheral field representations of V4 are connected with occipitoparietal areas DP (dorsal prelunate area), VIP (ventral intraparietal area), LIP (lateral intraparietal area), PIP (posterior intraparietal area), parieto-occipital area, and MST (medial STS area), and parahippocampal area TF (cytoarchitectonic area TF on the parahippocampal gyrus). Based on the distribution of labeled cells and terminals, projections from V4 to V2 and V3 are feedback, those to V3A, V4t, MT, DP, VIP, PIP, and FEF are the intermediate type, and those to FST, MST, LIP, TEO, TE, and TF are feedforward. Peripheral field projections from V4 to parietal areas could provide a direct route for rapid activation of circuits serving spatial vision and spatial attention. By contrast, the predominance of central field projections from V4 to inferior temporal areas is consistent with the need for detailed form analysis for object vision.

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    • "BOLD sensitivity to large neural networks may be one possible explanation for our finding that the colored Mondrians invoked a larger V1 BOLD signal magnitude than their achromatic counterparts. V4 was expected to activate preferably to the colored Mondrians, however, its connections to visual areas V3, V2, and V1 are extensive, including both feedback and feedforward communication (Ungerleider et al. 2008). Feedback communication from extrastriate regions does not affect neuronal spiking activity in the primary visual cortex, where firing activity is dependent on stimulation of the receptive field of the neuron (Budd 1998; Kim and Freeman 2014). "
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