Editing Visual cortex (section)

== Psychological model of the neural processing of visual information ==
{{Main|Two-streams hypothesis}}
[[File:Ventral-dorsal streams.svg|thumb|right|300px|The [[dorsal stream]] (green) and [[ventral stream]] (purple) are shown. They originate from primary visual cortex.]]

=== Ventral-dorsal model ===
V1 transmits information to two primary pathways, called the ventral stream and the dorsal stream.<ref>{{cite book |title=Computer Vision, Imaging and Computer Graphics Theory and Applications |location=Berlin, Germany | vauthors = Braz J, Pettré J, Richard P, Kerren A, Linsen L, Battiato S, Francisco I |publisher=[[Springer (publisher)|Springer]] |date=11 February 2016 |page=377 |isbn=978-3-319-29971-6 |chapter=Algorithmic Optimnizations in the HMAX Model Targeted for Efficient Object Recognition |chapter-url=https://books.google.com/books?id=hpKRCwAAQBAJ&pg=PA377 | veditors = Bitar AW, Mansour MM, Chehab A }}</ref>
* The '''[[Two-streams hypothesis#Ventral stream|ventral stream]]''' begins with V1, goes through visual area V2, then through visual area V4, and to the [[inferior temporal cortex]] (IT cortex). The ventral stream, sometimes called the "What Pathway", is associated with form recognition and object representation. It is also associated with storage of [[long-term memory]].
* The '''[[Two-streams hypothesis#Dorsal stream|dorsal stream]]''' begins with V1, goes through Visual area V2, then to the [[dorsomedial area]] (DM/V6) and middle temporal area (MT/V5) and to the [[posterior parietal cortex]]. The dorsal stream, sometimes called the "Where Pathway" or "How Pathway", is associated with motion, representation of object locations, and control of the eyes and arms, especially when visual information is used to guide [[saccade]]s or reaching.

The what vs. where account of the ventral/dorsal pathways was first described by [[Leslie Ungerleider|Ungerleider]] and [[Mortimer Mishkin|Mishkin]].<ref>{{cite book |title=Analysis of Visual Behavior |chapter=Two Cortical Visual Systems |chapter-url=https://archive.org/details/analysisofvisual00ingl |chapter-url-access=registration |vauthors=Ungerleider LG, Mishkin M |publisher=MIT Press |year=1982 |veditors=Ingle DJ, Goodale MA, Mansfield RJ |location=Boston |isbn=978-0-262-09022-3 |pages=[https://archive.org/details/analysisofvisual00ingl/page/549 549–586]}}</ref>

More recently, [[Melvyn A. Goodale|Goodale]] and Milner extended these ideas and suggested that the ventral stream is critical for visual perception whereas the dorsal stream mediates the visual control of skilled actions.<ref name="GoodaleMilner">{{cite journal | vauthors = Goodale MA, Milner AD | title = Separate visual pathways for perception and action | journal = Trends in Neurosciences | volume = 15 | issue = 1 | pages = 20–25 | date = January 1992 | pmid = 1374953 | doi = 10.1016/0166-2236(92)90344-8 | s2cid = 793980 | citeseerx = 10.1.1.207.6873 }}</ref> It has been shown that visual illusions such as the [[Ebbinghaus illusion]] distort judgements of a perceptual nature, but when the subject responds with an action, such as grasping, no distortion occurs.<ref name="Aglioti1995">{{cite journal | vauthors = Aglioti S, DeSouza JF, Goodale MA | title = Size-contrast illusions deceive the eye but not the hand | journal = Current Biology | volume = 5 | issue = 6 | pages = 679–685 | date = June 1995 | pmid = 7552179 | doi = 10.1016/S0960-9822(95)00133-3 | s2cid = 206111613 | doi-access = free | bibcode = 1995CBio....5..679A }}</ref>

Work such as that from Franz ''et al.''<ref name="Franz2005">{{cite journal | vauthors = Franz VH, Scharnowski F, Gegenfurtner KR | title = Illusion effects on grasping are temporally constant not dynamic | journal = Journal of Experimental Psychology. Human Perception and Performance | volume = 31 | issue = 6 | pages = 1359–1378 | date = December 2005 | pmid = 16366795 | doi = 10.1037/0096-1523.31.6.1359 }}</ref> suggests that both the action and perception systems are equally fooled by such illusions. Other studies, however, provide strong support for the idea that skilled actions such as grasping are not affected by pictorial illusions<ref name="Ganel2003">{{cite journal | vauthors = Ganel T, Goodale MA | title = Visual control of action but not perception requires analytical processing of object shape | journal = Nature | volume = 426 | issue = 6967 | pages = 664–667 | date = December 2003 | pmid = 14668865 | doi = 10.1038/nature02156 | s2cid = 4314969 | bibcode = 2003Natur.426..664G }}</ref><ref name="Ganel2008">{{cite journal | vauthors = Ganel T, Tanzer M, Goodale MA | title = A double dissociation between action and perception in the context of visual illusions: opposite effects of real and illusory size | journal = Psychological Science | volume = 19 | issue = 3 | pages = 221–225 | date = March 2008 | pmid = 18315792 | doi = 10.1111/j.1467-9280.2008.02071.x | s2cid = 15679825 }}</ref> and suggest that the action/perception dissociation is a useful way to characterize the functional division of labor between the dorsal and ventral visual pathways in the cerebral cortex.<ref name="Goodale2011">{{cite journal | vauthors = Goodale MA | title = Transforming vision into action | journal = Vision Research | volume = 51 | issue = 13 | pages = 1567–1587 | date = July 2011 | pmid = 20691202 | doi = 10.1016/j.visres.2010.07.027 | doi-access = free }}</ref>