Cortical visual areas in monkeys: location, topography, connections, columns, plasticity and cortical dynamics

Abstract

The visual system is constantly challenged to organize the retinal pattern of stimulation into coherent percepts. This task is achieved by the cortical visual system, which is composed by topographically organized analytic areas and by synthetic areas of the temporal lobe that have more holistic processing. Additional visual areas of the parietal lobe are related to motion perception and visuomotor control. V1 and V2 represent the entire visual field. MT represents only the binocular field, and V4 only the central 30 degrees-40 degrees. The parietal areas represent more of the periphery. For any eccentricity, the receptive field grows at each step of processing, more at anterior areas in the temporal lobe. Minimal point image size increases towards the temporal lobe, but remains fairly constant toward the parietal lobe. Patterns of projection show asymmetries. Central V2 and V4 project mainly to the temporal lobe, while peripherals V2 (more than 30 degrees) and V4 (more than 10 degrees) also project to the parietal lobe. Visual information that arrives at V1 projects to V2, MT and PO, which then project to other areas. Local lateral propagation and recursive loops corroborate to perceptual completion and filling in. Priority connections to temporal, parietal and parieto-temporal cortices help construct crude early representations of objects, trajectories and movements.

Topography and Areal Organization of Mouse Visual Cortex

“…For instance, ventral stream areas in primates primarily represent the central visual field, enhancing processing of object features near the fovea, whereas parietal visual areas tend to over-represent the periphery and process spatial relationships (for review, see Gattass et al, 2005). Our measurements show that mouse extrastriate visual areas have consistent biases in visual field coverage as well.…”

“…Lateral areas primarily emphasized the central visual field, whereas medial areas were biased toward the periphery. Incomplete and biased representations of space have also been observed in extrastriate areas of primates (Baizer et al, 1991;Gattass et al, 2005;Orban, 2008). However, such coverage biases appear more extreme in mice, which may be driven by the need for functionally specific encoding of localized regions of the visual field on a smaller cortex.…”

“…A necessary step toward the detailed study of the visual hierarchy is a thorough characterization of areal boundaries and visual field representations. Numerous primate studies have relied on established visual field maps as a framework for further investigation of the network (Van Essen, 2004;Gattass et al, 2005;Rosa and Tweedale, 2005;Wandell et al, 2007). In the visual cortex of mice, it is apparent that many fundamental questions about cortical computation can be addressed with far greater precision, thanks to powerful new experimental tools (Luo et al, 2008;Madisen et al, 2010;Huberman and Niell, 2011).…”

The Retinotopic Organization of the Human Middle Temporal Area MT/V5 and Its Cortical Neighbors

“…Kolster et al (2009), in suggesting that the retinotopic region ventral to the cluster was PITd, assumed that there was a second more ventral portion that was also retinotopically organized. There is evidence for such a ventral region (Gattass et al, 2005), but it was labeled TEO. We propose that the two human regions in the cluster below the MT/V5 cluster correspond to monkey PITd and PITv.…”

On the Spatial Metric of Short-SOA Costs of Exogenous Cuing

“…This cue-induced inhibition includes two components: One is sensory and resembles masking, whereas the other is oculomotor, probably as a result of the requirement to maintain fixation. Physiologic evidence shows that early in the visual system, such as within the lateral geniculate nucleus, and in the striate and extrastriate visual cortex, the structure of receptive fields linearly represents the spatial arrangement of visual stimuli (for reviews, see DeAngelis, Ohzawa, & Freeman, 1995;Gattass et al, 2005). Sensory competition between adjacent stimuli has also been shown in retinotopic brain areas (Schwartz et al, 2005).…”