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==Motion processing==
[[Akinetopsia]] is an intriguing condition brought about by damage to the [[Extrastriate cortex]] MT+ that renders [[humans]] and [[monkeys]] unable to perceive motion, seeing the world in a series of static "frames" instead<ref name="zihl1">{{cite journal|last=Zihl|first=J.|coauthors=von Cramon, D.Y., Mai N., Schmid, C.|year=1991|title=Disturbance of movement vision after bilateral posterior brain damage|journal=Brain|issue=144|doi=10.1093/brain/114.5.2235|pages=2235–2252|volume=114|pmid=1933243}}</ref><ref name="zihl2">{{cite journal|last=Zihl|first=J. |author2=von Cramon, D.Y. |author3=Mai, N.|year=1983|title=Selective disturbances of movement vision after bilateral brain damage|journal=Brain|issue=1062|doi=10.1093/brain/106.2.525-a|pages=313–340|volume=106}}</ref><ref name=Hess1989>{{cite journal | title=The" motion-blind" patient: low-level spatial and temporal filters | author=Hess, Baker, Zihl | journal=Journal of Neuroscience | year=1989 | volume=9 | issue=5 | pages=1628–1640 | pmid=2723744}}</ref><ref name=Baker1991>{{cite journal | title=Residual motion perception in a" motion-blind" patient, assessed with limited-lifetime random dot stimuli | author=Baker, Hess, Zihl | journal=Journal of Neuroscience | year=1991 | volume=11 | issue=2 | pages=454–461 | pmid=1992012}}</ref> and indicates that there might be a "motion centre" in the brain. Of course, such data can only indicate that this area is at least necessary to motion perception, not that it is sufficient; however, other evidence has shown the importance of this area to primate motion perception. Specifically, physiological, neuroimaging, perceptual, electrical- and [[transcranial magnetic stimulation]] evidence (Table 1) all come together on the area V5/hMT+. Converging evidence of this type is supportive of a module for motion processing. However, this view is likely to be incomplete: other areas are involved with [[motion perception]], including V1,<ref name="orban1">{{cite journal|last=Orban|first=G.A.|author2=Kennedy, H. |author3=Bullier, J. |year=1986|title=Velocity sensitivity and direction selectivity of neurons in areas V1 and V2 of the monkey: influence of eccentricity|journal=Journal of Neurophysiology|volume=56|issue=2|doi=10.1016/j.jphysparis.2004.03.004|pages=462–480|pmid=3760931}}</ref><ref name="mov1">{{cite journal|last=Movshon|first=J.A.|author2=Newsome, W.T. |year=1996|title=Visual response properties of striate cortical neurons projecting to area MT in macaque monkeys|journal=Journal of Neuroscience|volume=16|issue=23|pages=7733–7741|pmid=8922429}}</ref><ref>{{cite journal|last=Born|first=R.T.|author2=Bradley, D.C. |year=2005|title=Structure and function of visual area MT|journal=Annual Review of Neuroscience|volume=28|pages=157–189|pmid=16022593|doi=10.1146/annurev.neuro.26.041002.131052}}</ref> V2 and V3a <ref>{{cite journal|last=Grill-Spector|first=K.|author2=Malach, R. |year=2004|title=The Human Visual Cortex|journal=Annual Review of Neuroscience|volume=7|pages=649–677|doi=10.1146/annurev.neuro.27.070203.144220|pmid=15217346}}</ref> and areas surrounding V5/hMT+ (Table 2). A recent fMRI study put the number of motion areas at twenty-one.<ref name="stiers">{{cite journal|last=Stiers|first=P|coauthors=Peeters, R; Lagae, L; Van Hecke, P; Sunaert, S|title=Mapping multiple visual areas in the human brain with a short fMRI sequence|journal=NeuroImage|date=Jan 1, 2006|volume=29|issue=1|pages=74–89|doi=10.1016/j.neuroimage.2005.07.033|pmid=16154766|url=http://www.sciencedirect.com/science/article/pii/S1053811905005070|accessdate=28 April 2013}}</ref> Clearly, this constitutes a stream of diverse anatomical areas. The extent to which this is ‘pure’ is in question: with Akinetopsia come severe difficulties in obtaining structure from motion.<ref name=rizzo>{{cite journal|last=Rizzo|first=Matthew|author2=Nawrot, Mark |author3=Zihl, Josef |title=Motion and shape perception in cerebral akinetopsia|journal=Brain|date=1 January 1995|volume=118|issue=5|pages=1105–1127|doi=10.1093/brain/118.5.1105|pmid=7496774}}</ref> [[V5/hMT+]] has since been implicated in this function<ref name=grunewald>{{cite journal|last=Grunewald|first=A|author2=Bradley, DC |author3=Andersen, RA |title=Neural correlates of structure-from-motion perception in macaque V1 and MT|journal=The Journal of neuroscience : the official journal of the Society for Neuroscience|date=Jul 15, 2002|volume=22|issue=14|pages=6195–207|pmid=12122078}}</ref> as well as determining depth.<ref name=angelis>{{cite journal|last=DeAngelis|first=GC|author2=Cumming, BG |author3=Newsome, WT |title=Cortical area MT and the perception of stereoscopic depth|journal=Nature|date=Aug 13, 1998|volume=394|issue=6694|pages=677–80|doi=10.1038/29299|pmid=9716130}}</ref> Thus the current evidence suggests that motion processing occurs in a modular stream, although with a role in form and depth perception at higher levels.
{| class="wikitable"
| [[Physiology]] (single cell recording)
| Cells directionally and speed selective in MT/V5
| <ref name=zeki1>{{cite journal|last=Zeki|first=SM|title=Functional organization of a visual area in the posterior bank of the superior temporal sulcus of the rhesus monkey|journal=The Journal of physiologyPhysiology|date=Feb 1974|volume=236|issue=3|pages=549–73|pmid=4207129|pmc=1350849}}</ref><ref name=vanessen1>{{cite journal|last=Van Essen|first=D. C.|author2=Maunsell, J. H. R. |author3=Bixby, J. L. |title=The middle temporal visual area in the macaque: Myeloarchitecture, connections, functional properties and topographic organization|journal=The Journal of Comparative Neurology|date=1 July 1981|volume=199|issue=3|pages=293–326|doi=10.1002/cne.901990302|pmid=7263951}}</ref><ref name=maunsell>{{cite journal|last=Maunsell|first=JH|author2=Van Essen, DC|title=Functional properties of neurons in middle temporal visual area of the macaque monkey. I. Selectivity for stimulus direction, speed, and orientation|journal=Journal of neurophysiologyNeurophysiology|date=May 1983|volume=49|issue=5|pages=1127–47|pmid=6864242}}</ref><ref name=felleman>{{cite journal|last=Felleman|first=DJ|author2=Kaas, JH |title=Receptive-field properties of neurons in middle temporal visual area (MT) of owl monkeys|journal=Journal of neurophysiologyNeurophysiology|date=Sep 1984|volume=52|issue=3|pages=488–513|pmid=6481441}}</ref>
|-
| [[Neuroimaging]]
| Greater activation for motion information than static information in [[Visual cortex#V5.2FMT|V5/MT]]
| <ref name="stiers"/><ref name=culham1>{{cite journal|last=Culham|first=JC|author2=Brandt, SA |author3=Cavanagh, P |author4=Kanwisher, NG |author5=Dale, AM |author6= Tootell, RB |title=Cortical fMRI activation produced by attentive tracking of moving targets|journal=Journal of neurophysiologyNeurophysiology|date=Nov 1998|volume=80|issue=5|pages=2657–70|pmid=9819271}}</ref>
|-
| Electrical-stimulation & perceptual
| [[Magnetic]]-stimulation
| Motion perception is also briefly impaired in humans by a strong magnetic pulse over the corresponding scalp region to hMT+
| <ref name=hotson>{{cite journal|last=Hotson|first=John|author2=Braun, Doris |author3=Herzberg, William |author4= Boman, Duane |title=Transcranial magnetic stimulation of extrastriate cortex degrades human motion direction discrimination|journal=Vision Research|year=1994|volume=34|issue=16|pages=2115–2123|doi=10.1016/0042-6989(94)90321-2|pmid=7941409}}</ref><ref name=beckers>{{cite journal|last=Beckers|first=G.|author2=Zeki, S. |title=The consequences of inactivating areas V1 and V5 on visual motion perception|journal=Brain|date=1 January 1995|volume=118|issue=1|pages=49–60|doi=10.1093/brain/118.1.49|pmid=7895014}}</ref><ref name=walsh>{{cite journal|last=Walsh|first=V|author2=Cowey, A |title=Magnetic stimulation studies of visual cognition|journal=Trends in cognitiveCognitive sciencesSciences|date=Mar 1, 1998|volume=2|issue=3|pages=103–10|doi=10.1016/S1364-6613(98)01134-6|pmid=21227086}}</ref>
|-
| [[Psychophysics]]
| [[Physiology]] (single cell recording)
| Complex motion involving contraction/expansion and rotation found to activate neurons in medial superior temporal area (MST)
| <ref name=tanaka>{{cite journal|last=Tanaka|first=K|author2=Saito, H |title=Analysis of motion of the visual field by direction, expansion/contraction, and rotation cells clustered in the dorsal part of the medial superior temporal area of the macaque monkey|journal=Journal of neurophysiologyNeurophysiology|date=Sep 1989|volume=62|issue=3|pages=626–41|pmid=2769351}}</ref>
|-
| [[Neuroimaging]]
== Color processing ==
Similar converging evidence suggests modularity for color. Beginning with Gowers’ finding<ref name=gowers>{{cite book|last=Gowers|first=W.|title=A manual of diseases of the brain|year=1888|publisher=J & A Churchill}}</ref> that damage to the fusiform/lingual [[gyri]] in [[occipitotemporal cortex]] correlates with a loss in color perception ([[achromatopsia]]), the notion of a "color centre" in the primate brain has had growing support.<ref name=meadows>{{cite journal|last=Meadows|first=JC|title=Disturbed perception of colours associated with localized cerebral lesions|journal=Brain : a journal of neurology|date=Dec 1974|volume=97|issue=4|pages=615–32|doi=10.1093/brain/97.1.615|pmid=4547992}}</ref><ref name=zeki2>{{cite journal|last=Zeki|first=S.|title=Parallelism and Functional Specialization in Human Visual Cortex|journal=Cold Spring Harbor Symposia on Quantitative Biology|date=1 January 1990|volume=55|issue=0|pages=651–661|doi=10.1101/SQB.1990.055.01.062}}</ref><ref name=grusser>{{cite book|last=Grüsser and Landis|title=Visual agnosias and other disturbances of visual perception and cognition|year=1991|publisher=MacMillan|pages=297–303}}</ref> Again, such clinical evidence only implies that this region is critical to color [[perception]], and nothing more. Other evidence, however, including [[neuroimaging]]<ref name="stiers"/><ref name=barzek2>{{Cite journal |author=Bartels, A. & Zeki, S. |title=Brain dynamics during natural viewing conditions - a new guide for mapping connectivity ''in vivo'' |journal=[[NeuroImage]] |volume=24 |issue=2 |pages=339–349 |year=2005 |doi=10.1016/j.neuroimage.2004.08.044 |quote=no |pmid=15627577}}</ref><ref name=barzek1>{{Cite journal |author=Bartels, A. & Zeki, S. |title=The architecture of the colour centre in the human visual brain: new results and a review |journal=[[European Journal of Neuroscience]] |volume=12 |issue=1 |pages=172–193 |year=2000 |doi=10.1046/j.1460-9568.2000.00905.x |quote=no |pmid=10651872}}</ref> and physiology<ref name=wachtler>{{cite journal|last=Wachtler|first=T|author2=Sejnowski, TJ |author3=Albright, TD |title=Representation of color stimuli in awake macaque primary visual cortex|journal=Neuron|date=Feb 20, 2003|volume=37|issue=4|pages=681–91|doi=10.1016/S0896-6273(03)00035-7|pmid=12597864|pmc=2948212}}</ref><ref name=kusunoki>{{cite journal|last=Kusunoki|first=M|author2=Moutoussis, K |author3=Zeki, S |title=Effect of background colors on the tuning of color-selective cells in monkey area V4|journal=Journal of neurophysiologyNeurophysiology|date=May 2006|volume=95|issue=5|pages=3047–59|doi=10.1152/jn.00597.2005|pmid=16617176}}</ref> converges on V4 as necessary to color perception. A recent [[meta-analysis]] has also shown a specific [[lesion]] common to achromats corresponding to V4.<ref name=bouvier>{{cite journal|last=Bouvier|first=S. E.|author2=Engel, SA |title=Behavioral Deficits and Cortical Damage Loci in Cerebral Achromatopsia|journal=Cerebral Cortex|date=27 April 2005|volume=16|issue=2|pages=183–191|doi=10.1093/cercor/bhi096|pmid=15858161}}</ref> From another direction altogether it has been found that when [[synesthesia|synaesthetes]] experience color by a non-visual stimulus, V4 is active.<ref name=rich>{{cite journal|last=Rich|first=AN|author2=Williams, MA |author3=Puce, A |author4=Syngeniotis, A |author5=Howard, MA |author6=McGlone, F |author7= Mattingley, JB |title=Neural correlates of imagined and synaesthetic colours|journal=Neuropsychologia|year=2006|volume=44|issue=14|pages=2918–25|doi=10.1016/j.neuropsychologia.2006.06.024|pmid=16901521}}</ref><ref name=sperling>{{cite journal|last=Sperling|first=JM|author2=Prvulovic, D |author3=Linden, DE |author4=Singer, W |author5= Stirn, A |title=Neuronal correlates of colour-graphemic synaesthesia: a fMRI study|journal=Cortex; a journal devoted to the study of the nervous system and behavior|date=Feb 2006|volume=42|issue=2|pages=295–303|doi=10.1016/S0010-9452(08)70355-1|pmid=16683504}}</ref> On the basis of this evidence it would seem that color processing is modular. However, as with motion processing it is likely that this conclusion is inaccurate. Other evidence shown in Table 3 implies different areas’ involvement with color. It may thus be more instructive to consider a multistage color processing stream from the retina through to cortical areas including at least [[Visual cortex#Primary visual cortex .28V1.29|V1]], [[Visual cortex#V2|V2]], [[Visual cortex#V4|V4]], PITd and TEO. Consonant with motion perception, there appears to be a constellation of areas drawn upon for [[color perception]]. In addition, V4 may have a special, but not exclusive, role. For example, single cell recording has shown that only V4 cells respond to the color of a stimuli rather than its waveband, whereas other areas involved with color do not.<ref name=wachtler/><ref name=kusunoki/>
{| class="wikitable"
|-
| Shape detection
| <ref name=pasupathy>{{cite journal|last=Pasupathy|first=A|title=Neural basis of shape representation in the primate brain|journal=Progress in brain research|year=2006|volume=154|pages=293–313|pmid=17010719|doi=10.1016/S0079-6123(06)54016-6|series=Progress in Brain Research|isbn=9780444529664}}</ref><ref name=david>{{cite journal|last=David|first=SV|author2=Hayden, BY |author3=Gallant, JL |title=Spectral receptive field properties explain shape selectivity in area V4|journal=Journal of neurophysiologyNeurophysiology|date=Dec 2006|volume=96|issue=6|pages=3492–505|pmid=16987926|doi=10.1152/jn.00575.2006}}</ref>
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| Link between [[Visual perception|vision]], [[attention]] and [[cognition]]
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