Editing Visual cortex (section)

== Third visual cortex, including area V3 ==
[[File:Visual field maps.jpg|thumb|left|A visual field map of the primary visual cortex and the numerous extrastriate areas. More images in [[Colour centre]]]]

The term '''third visual complex''' refers to the region of cortex located immediately in front of V2, which includes the region named '''visual area V3''' in humans. The "complex" nomenclature is justified by the fact that some controversy still exists regarding the exact extent of area V3, with some researchers proposing that the cortex located in front of V2 may include two or three functional subdivisions. For example, David Van Essen and others (1986) have proposed the existence of a "dorsal V3" in the upper part of the cerebral hemisphere, which is distinct from the "ventral V3" (or ventral posterior area, VP) located in the lower part of the brain. Dorsal and ventral V3 have distinct connections with other parts of the brain, appear different in sections stained with a variety of methods, and contain neurons that respond to different combinations of visual stimulus (for example, colour-selective neurons are more common in the ventral V3). Additional subdivisions, including V3A and V3B have also been reported in humans. These subdivisions are located near dorsal V3, but do not adjoin V2.

Dorsal V3 is normally considered to be part of the dorsal stream, receiving inputs from V2 and from the primary visual area and projecting to the posterior [[parietal cortex]]. It may be anatomically located in [[Brodmann area 19]]. Braddick using fMRI has suggested that area V3/V3A may play a role in the processing of [[global motion]]<ref name="Braddick2001">{{cite journal | vauthors = Braddick OJ, O'Brien JM, Wattam-Bell J, Atkinson J, Hartley T, Turner R | title = Brain areas sensitive to coherent visual motion | journal = Perception | volume = 30 | issue = 1 | pages = 61–72 | year = 2001 | pmid = 11257978 | doi = 10.1068/p3048 | s2cid = 24081674 }}</ref> Other studies prefer to consider dorsal V3 as part of a larger area, named the [[dorsomedial area]] (DM), which contains a representation of the entire visual field. Neurons in area DM respond to coherent motion of large patterns covering extensive portions of the visual field (Lui and collaborators, 2006).

Ventral V3 (VP), has much weaker connections from the primary visual area, and stronger connections with the [[inferior temporal cortex]]. While earlier studies proposed that VP contained a representation of only the upper part of the visual field (above the point of fixation), more recent work indicates that this area is more extensive than previously appreciated, and like other visual areas it may contain a complete visual representation. The revised, more extensive VP is referred to as the ventrolateral posterior area (VLP) by Rosa and Tweedale.<ref>{{cite journal | vauthors = Rosa MG, Tweedale R | title = Visual areas in lateral and ventral extrastriate cortices of the marmoset monkey | journal = The Journal of Comparative Neurology | volume = 422 | issue = 4 | pages = 621–651 | date = July 2000 | pmid = 10861530 | doi = 10.1002/1096-9861(20000710)422:4<621::AID-CNE10>3.0.CO;2-E | s2cid = 25982910 }}</ref>