Visual modularity explained

In cognitive neuroscience, visual modularity is an organizational concept concerning how vision works. The way in which the primate visual system operates is currently under intense scientific scrutiny. One dominant thesis is that different properties of the visual world (color, motion, form and so forth) require different computational solutions which are implemented in anatomically/functionally distinct regions that operate independently – that is, in a modular fashion.[1]

Motion processing

Akinetopsia, a term coined by Semir Zeki,[2] refers to an intriguing condition brought about by damage to the Extrastriate cortex MT+ (also known as area V5) that renders humans and monkeys unable to perceive motion, seeing the world in a series of static "frames" instead[3] [4] [5] [6] 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,[7] [8] [9] V2 and V3a [10] and areas surrounding V5/hMT+ (Table 2). A recent fMRI study put the number of motion areas at twenty-one.[11] 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.[12] V5/hMT+ has since been implicated in this function[13] as well as determining depth.[14] 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.

Evidence for a "motion centre" in the primate brain! Methodology ! Finding! Source
Physiology (single cell recording)Cells directionally and speed selective in MT/V5[15] [16] [17] [18]
NeuroimagingGreater activation for motion information than static information in V5/MT[19]
Electrical-stimulation & perceptualFollowing electrical stimulation of V5/MT cells perceptual decisions are biased towards the stimulated neuron's direction preference[20]
Magnetic-stimulationMotion perception is also briefly impaired in humans by a strong magnetic pulse over the corresponding scalp region to hMT+[21] [22] [23]
PsychophysicsPerceptual asynchrony among motion, color and orientation.[24] [25]
Evidence for a motion processing area surrounding V5! Methodology ! Finding! Source
Physiology (single cell recording)Complex motion involving contraction/expansion and rotation found to activate neurons in medial superior temporal area (MST)[26]
NeuroimagingBiological motion activated superior temporal sulcus[27]
NeuroimagingTool use activated middle temporal gyrus and inferior temporal sulcus[28]
NeuropsychologyDamage to visual area V5 results in akinetopsia

Color processing

Similar converging evidence suggests modularity for color. Beginning with Gowers’ finding[29] 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.[30] [31] [32] Again, such clinical evidence only implies that this region is critical to color perception, and nothing more. Other evidence, however, including neuroimaging[11] [33] [34] and physiology[35] [36] converges on V4 as necessary to color perception. A recent meta-analysis has also shown a specific lesion common to achromats corresponding to V4.[37] From another direction altogether it has been found that when synaesthetes experience color by a non-visual stimulus, V4 is active.[38] [39] 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 V1, V2, 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.[35] [36]

Evidence against a "color center" in the primate brain! Other areas involved with color/Other functions of V4! Source
Wavelength sensitive cells in V1 and V2[40] [41]
anterior parts of the inferior temporal cortex[42] [43]
posterior parts of the superior temporal sulcus (PITd)[44]
Area in or near TEO[45]
Shape detection[46] [47]
Link between vision, attention and cognition[48]

Form processing

Another clinical case that would a priori suggest a module for modularity in visual processing is visual agnosia. The well studied patient DF is unable to recognize or discriminate objects[49] owing to damage in areas of the lateral occipital cortex although she can see scenes without problem – she can literally see the forest but not the trees.[50] Neuroimaging of intact individuals reveals strong occipito-temporal activation during object presentation and greater activation still for object recognition.[51] Of course, such activation could be due to other processes, such as visual attention. However, other evidence that shows a tight coupling of perceptual and physiological changes[52] suggests activation in this area does underpin object recognition. Within these regions are more specialized areas for face or fine grained analysis,[53] place perception[54] and human body perception.[55] Perhaps some of the strongest evidence for the modular nature of these processing systems is the double dissociation between object- and face (prosop-) agnosia. However, as with color and motion, early areas (see [46] for a comprehensive review) are implicated too, lending support to the idea of a multistage stream terminating in the inferotemporal cortex rather than an isolated module.

Functional modularity

One of the first uses of the term "module" or "modularity" occurs in the influential book "Modularity of Mind" by philosopher Jerry Fodor.[56] A detailed application of this idea to the case of vision was published by Pylyshyn (1999), who argued that there is a significant part of vision that is not responsive to beliefs and is "cognitively impenetrable".[57]

Much of the confusion concerning modularity exists in neuroscience because there is evidence for specific areas (e.g. V4 or V5/hMT+) and the concomitant behavioral deficits following brain insult (thus taken as evidence for modularity). In addition, evidence shows other areas are involved and that these areas subserve processing of multiple properties (e.g. V1[58]) (thus taken as evidence against modularity). That these streams have the same implementation in early visual areas, like V1, is not inconsistent with a modular viewpoint: to adopt the canonical analogy in cognition, it is possible for different software to run on the same hardware. A consideration of psychophysics and neuropsychological data would suggest support for this. For example, psychophysics has shown that percepts for different properties are realized asynchronously.[24] [25] In addition, although achromats experience other cognitive defects[59] they do not have motion deficits when their lesion is restricted to V4, or total loss of form perception.[60] Relatedly, Zihl and colleagues' akinetopsia patient shows no deficit to color or object perception (although deriving depth and structure from motion is problematic, see above) and object agnostics do not have damaged motion or color perception, making the three disorders triply dissociable.[4] Taken together this evidence suggests that even though distinct properties may employ the same early visual areas they are functionally independent. Furthermore, that the intensity of subjective perceptual experience (e.g. color) correlates with activity in these specific areas (e.g. V4),[33] the recent evidence that synaesthetes show V4 activation during the perceptual experience of color, as well as the fact that damage to these areas results in concomitant behavioral deficits (the processing may be occurring but perceivers do not have access to the information) are all evidence for visual modularity.

See also

Notes and References

  1. Calabretta. R.. Parisi, D. . 2005. Evolutionary Connectionism and Mind/Brain Modularity. Modularity. Understanding the Development and Evolution of Complex Natural Systems. 10.1098/rstb.2005.1807. 309–330. 16524839. 361. 1467. 1609335.
  2. ZEKI. S.. Cerebral Akinetopsia (Visual Motion Blindness). 1991-04-01. Brain. 114. 2. 811–824. 10.1093/brain/114.2.811. 2043951. 0006-8950.
  3. Zihl J, von Cramon D, Mai N, Schmid C . 1991. Disturbance of movement vision after bilateral posterior brain damage. Brain. 144. 10.1093/brain/114.5.2235. 2235–2252. 114. 1933243.
  4. Zihl. J. . von Cramon, D.Y. . Mai, N.. 1983. Selective disturbances of movement vision after bilateral brain damage. Brain. 2. 10.1093/brain/106.2.525-a. 313–340. 106.
  5. Hess RH, Baker CL, Zihl J . The "motion-blind" patient: low-level spatial and temporal filters . J. Neurosci. . 9 . 5 . 1628–40 . 1989 . 2723744 . 10.1523/JNEUROSCI.09-05-01628.1989. free . 6569833 .
  6. Residual motion perception in a" motion-blind" patient, assessed with limited-lifetime random dot stimuli . Baker CL, Hess RF, Zihl J . Journal of Neuroscience . 1991 . 11 . 2 . 454–461 . 1992012. 10.1523/JNEUROSCI.11-02-00454.1991 . free . 6575225 .
  7. Orban. G.A.. Kennedy, H. . Bullier, J. . 1986. Velocity sensitivity and direction selectivity of neurons in areas V1 and V2 of the monkey: influence of eccentricity. Journal of Neurophysiology. 56. 2. 10.1016/j.jphysparis.2004.03.004. 462–480. 3760931. 26116687 .
  8. Movshon. J.A.. Newsome, W.T. . 1996. Visual response properties of striate cortical neurons projecting to area MT in macaque monkeys. Journal of Neuroscience. 16. 23. 7733–7741. 8922429. 10.1523/JNEUROSCI.16-23-07733.1996. 6579106. free.
  9. Born. R.T.. Bradley, D.C. . 2005. Structure and function of visual area MT. Annual Review of Neuroscience. 28. 157–189. 16022593. 10.1146/annurev.neuro.26.041002.131052.
  10. Grill-Spector. K.. Malach, R. . 2004. The Human Visual Cortex. Annual Review of Neuroscience. 27. 649–677. 10.1146/annurev.neuro.27.070203.144220. 15217346.
  11. Stiers P, Peeters R, Lagae L, Van Hecke P, Sunaert S . Mapping multiple visual areas in the human brain with a short fMRI sequence. NeuroImage. Jan 1, 2006. 29. 1. 74–89. 10.1016/j.neuroimage.2005.07.033. 16154766. 24485857 . free.
  12. Rizzo. Matthew. Mark Nawrot. Nawrot, Mark . Zihl, Josef . Motion and shape perception in cerebral akinetopsia. Brain. 1 January 1995. 118. 5. 1105–1127. 10.1093/brain/118.5.1105. 7496774.
  13. Grunewald. A. Bradley, DC . Andersen, RA . Neural correlates of structure-from-motion perception in macaque V1 and MT. The Journal of Neuroscience. Jul 15, 2002. 22. 14. 6195–207. 12122078. 10.1523/JNEUROSCI.22-14-06195.2002. 6757912. free.
  14. DeAngelis. GC. Cumming, BG . Newsome, WT . Cortical area MT and the perception of stereoscopic depth. Nature. Aug 13, 1998. 394. 6694. 677–80. 10.1038/29299. 9716130. 1998Natur.394..677D . 4419753 .
  15. Zeki. SM. Functional organization of a visual area in the posterior bank of the superior temporal sulcus of the rhesus monkey. The Journal of Physiology. Feb 1974. 236. 3. 549–73. 4207129. 1350849. 10.1113/jphysiol.1974.sp010452.
  16. Van Essen. D. C.. Maunsell, J. H. R. . Bixby, J. L. . The middle temporal visual area in the macaque: Myeloarchitecture, connections, functional properties and topographic organization. The Journal of Comparative Neurology. 1 July 1981. 199. 3. 293–326. 10.1002/cne.901990302. 7263951. 19578153 .
  17. Maunsell. JH. Van Essen, DC. Functional properties of neurons in middle temporal visual area of the macaque monkey. I. Selectivity for stimulus direction, speed, and orientation. Journal of Neurophysiology. May 1983. 49. 5. 1127–47. 6864242. 10.1152/jn.1983.49.5.1127.
  18. Felleman. DJ. Kaas, JH . Receptive-field properties of neurons in middle temporal visual area (MT) of owl monkeys. Journal of Neurophysiology. Sep 1984. 52. 3. 488–513. 6481441. 10.1152/jn.1984.52.3.488.
  19. Culham. JC. Brandt, SA . Cavanagh, P . Kanwisher, NG . Dale, AM . Tootell, RB . Cortical fMRI activation produced by attentive tracking of moving targets. Journal of Neurophysiology. Nov 1998. 80. 5. 2657–70. 9819271. 10.1152/jn.1998.80.5.2657.
  20. Salzman. CD. Murasugi, CM . Britten, KH . Newsome, WT . Microstimulation in visual area MT: effects on direction discrimination performance. The Journal of Neuroscience. Jun 1992. 12. 6. 2331–55. 1607944. 10.1523/JNEUROSCI.12-06-02331.1992. 6575906. free.
  21. Hotson. John. Braun, Doris . Herzberg, William . Boman, Duane . Transcranial magnetic stimulation of extrastriate cortex degrades human motion direction discrimination. Vision Research. 1994. 34. 16. 2115–2123. 10.1016/0042-6989(94)90321-2. 7941409. 25382683 .
  22. Beckers. G.. Zeki, S. . The consequences of inactivating areas V1 and V5 on visual motion perception. Brain. 1 January 1995. 118. 1. 49–60. 10.1093/brain/118.1.49. 7895014.
  23. Walsh. V. Cowey, A . Magnetic stimulation studies of visual cognition. Trends in Cognitive Sciences. Mar 1, 1998. 2. 3. 103–10. 10.1016/S1364-6613(98)01134-6. 21227086. 16473802.
  24. Moutoussis. K.. Zeki, S. . A direct demonstration of perceptual asynchrony in vision. Proceedings of the Royal Society B: Biological Sciences. 22 March 1997. 264. 1380. 393–399. 10.1098/rspb.1997.0056. 9107055. 1688275.
  25. Viviani. Paolo. Aymoz, Christelle . Colour, form, and movement are not perceived simultaneously. Vision Research. 1 October 2001. 41. 22. 2909–2918. 10.1016/S0042-6989(01)00160-2. 11701183.
  26. Tanaka. K. Saito, H . 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 of Neurophysiology. Sep 1989. 62. 3. 626–41. 2769351. 10.1152/jn.1989.62.3.626.
  27. Grossman. E. Donnelly, M . Price, R . Pickens, D . Morgan, V . Neighbor, G . Blake, R . Brain areas involved in perception of biological motion. Journal of Cognitive Neuroscience. Sep 2000. 12. 5. 711–20. 10.1162/089892900562417. 11054914. 10.1.1.138.1319. 15679202.
  28. Beauchamp. MS. Lee, KE . Haxby, JV . Martin, A . FMRI responses to video and point-light displays of moving humans and manipulable objects. Journal of Cognitive Neuroscience. Oct 1, 2003. 15. 7. 991–1001. 10.1162/089892903770007380. 14614810. 120898 .
  29. Book: Gowers, W.. A manual of diseases of the brain. 1888. J & A Churchill.
  30. Meadows. JC. Disturbed perception of colours associated with localized cerebral lesions. Brain: A Journal of Neurology. Dec 1974. 97. 4. 615–32. 10.1093/brain/97.1.615. 4547992.
  31. Zeki. S.. Parallelism and Functional Specialization in Human Visual Cortex. Cold Spring Harbor Symposia on Quantitative Biology. 1 January 1990. 55. 651–661. 10.1101/SQB.1990.055.01.062. 2132845.
  32. Book: Grüsser and Landis. Visual agnosias and other disturbances of visual perception and cognition. 1991. MacMillan. 297–303.
  33. Bartels, A. . Zeki, S. . amp . Brain dynamics during natural viewing conditions - a new guide for mapping connectivity in vivo . . 24 . 2 . 339–349 . 2005 . 10.1016/j.neuroimage.2004.08.044 . no . 15627577. 16882384 .
  34. Bartels, A. . Zeki, S. . amp . The architecture of the colour centre in the human visual brain: new results and a review . . 12 . 1 . 172–193 . 2000 . 10.1046/j.1460-9568.2000.00905.x . no . 10651872. 6787155 .
  35. Wachtler. T. Sejnowski, TJ . Albright, TD . Representation of color stimuli in awake macaque primary visual cortex. Neuron. Feb 20, 2003. 37. 4. 681–91. 10.1016/S0896-6273(03)00035-7. 12597864. 2948212.
  36. Kusunoki. M. Moutoussis, K . Zeki, S . Effect of background colors on the tuning of color-selective cells in monkey area V4. Journal of Neurophysiology. May 2006. 95. 5. 3047–59. 10.1152/jn.00597.2005. 16617176.
  37. Bouvier. S. E.. Engel, SA . Behavioral Deficits and Cortical Damage Loci in Cerebral Achromatopsia. Cerebral Cortex. 27 April 2005. 16. 2. 183–191. 10.1093/cercor/bhi096. 15858161. free.
  38. Rich. AN. Williams, MA . Puce, A . Syngeniotis, A . Howard, MA . McGlone, F . Mattingley, JB . Neural correlates of imagined and synaesthetic colours. Neuropsychologia. 2006. 44. 14. 2918–25. 10.1016/j.neuropsychologia.2006.06.024. 16901521. 6047634 .
  39. Sperling. JM. Prvulovic, D . Linden, DE . Singer, W . Stirn, A . Neuronal correlates of colour-graphemic synaesthesia: a fMRI study. Cortex. Feb 2006. 42. 2. 295–303. 10.1016/S0010-9452(08)70355-1. 16683504. 1559357 .
  40. Livingstone. MS. Hubel, DH . Anatomy and physiology of a color system in the primate visual cortex. The Journal of Neuroscience. Jan 1984. 4. 1. 309–56. 6198495. 10.1523/JNEUROSCI.04-01-00309.1984. 6564760. free.
  41. DeYoe. EA. Van Essen, DC. Segregation of efferent connections and receptive field properties in visual area V2 of the macaque. Nature. Sep 5–11, 1985. 317. 6032. 58–61. 10.1038/317058a0. 2412132. 1985Natur.317...58D . 4249013 .
  42. Zeki. S. Marini, L . Three cortical stages of colour processing in the human brain. Brain. 1998. 121. 9. 1669–1685. 10.1093/brain/121.9.1669. 9762956. free.
  43. Beauchamp. MS. Haxby, JV . Rosen, AC . DeYoe, EA . A functional MRI case study of acquired cerebral dyschromatopsia. Neuropsychologia. 2000. 38. 8. 1170–9. 10.1016/S0028-3932(00)00017-8. 10838151. 10372901 .
  44. Conway. B. R.. Tsao, DY . Color Architecture in Alert Macaque Cortex Revealed by fMRI. Cerebral Cortex. 22 December 2005. 16. 11. 1604–1613. 10.1093/cercor/bhj099. 16400160. 9100861 . free.
  45. Tootell. R. B.H.. Nelissen, K . Vanduffel, W . Orban, GA . Search for Color 'Center(s)' in Macaque Visual Cortex. Cerebral Cortex. 1 April 2004. 14. 4. 353–363. 10.1093/cercor/bhh001. 15028640. free.
  46. Book: Pasupathy, A. Neural basis of shape representation in the primate brain. 2006. 154. 293–313. 17010719. 10.1016/S0079-6123(06)54016-6. Progress in Brain Research. 9780444529664. Visual Perception - Fundamentals of Vision: Low and Mid-Level Processes in Perception.
  47. David. SV. Hayden, BY . Gallant, JL . Spectral receptive field properties explain shape selectivity in area V4. Journal of Neurophysiology. Dec 2006. 96. 6. 3492–505. 16987926. 10.1152/jn.00575.2006.
  48. Chelazzi. L. Miller, EK . Duncan, J . Desimone, R . Responses of neurons in macaque area V4 during memory-guided visual search. Cerebral Cortex. Aug 2001. 11. 8. 761–72. 10.1093/cercor/11.8.761. 11459766.
  49. Mishkin. Mortimer. Ungerleider, Leslie G. . Macko, Kathleen A. . Object vision and spatial vision: two cortical pathways. Trends in Neurosciences. 1983. 6. 414–417. 10.1016/0166-2236(83)90190-X. 15565609 .
  50. Steeves. Jennifer K.E.. Culham, Jody C. . Duchaine, Bradley C. . Pratesi, Cristiana Cavina . Valyear, Kenneth F. . Schindler, Igor . Humphrey, G. Keith . Milner, A. David . Goodale, Melvyn A. . The fusiform face area is not sufficient for face recognition: Evidence from a patient with dense prosopagnosia and no occipital face area. Neuropsychologia. 2006. 44. 4. 594–609. 10.1016/j.neuropsychologia.2005.06.013. 16125741. 460887 .
  51. Grill-Spector. Kalanit. Ungerleider, Leslie G. . Macko, Kathleen A. . The neural basis of object perception. Current Opinion in Neurobiology. 2003. 13. 3. 159–166. 10.1016/S0959-4388(03)00060-6. 12744968. 54383849 . free.
  52. Sheinberg. DL. Logothetis, NK . Noticing familiar objects in real world scenes: the role of temporal cortical neurons in natural vision. The Journal of Neuroscience. Feb 15, 2001. 21. 4. 1340–50. 11160405. 10.1523/JNEUROSCI.21-04-01340.2001. 6762229. free.
  53. Gauthier. I. Skudlarski, P . Gore, JC . Anderson, AW . Expertise for cars and birds recruits brain areas involved in face recognition. Nature Neuroscience. Feb 2000. 3. 2. 191–7. 10.1038/72140. 10649576. 15752722.
  54. Epstein. R. Kanwisher, N . A cortical representation of the local visual environment. Nature. Apr 9, 1998. 392. 6676. 598–601. 10.1038/33402. 9560155. 1998Natur.392..598E. 920141.
  55. Downing. PE. Jiang, Y . Shuman, M . Kanwisher, N . A cortical area selective for visual processing of the human body. Science. Sep 28, 2001. 293. 5539. 2470–3. 10.1126/science.1063414. 11577239. 2001Sci...293.2470D . 10.1.1.70.6526. 1564641 .
  56. Book: Fodor, Jerry A.. The modularity of mind : an essay on faculty psychology. 1989. MIT Press. Cambridge, Mass. [u.a.]. 978-0-262-56025-2. 6. printing..
  57. Pylyshyn. Z. Is vision continuous with cognition? The case for cognitive impenetrability of visual perception. The Behavioral and Brain Sciences. Jun 1999. 22. 3. 341–65; discussion 366–423. 11301517. 10.1017/s0140525x99002022. 9482993.
  58. Leventhal. AG. Thompson, KG . Liu, D . Zhou, Y . Ault, SJ . Concomitant sensitivity to orientation, direction, and color of cells in layers 2, 3, and 4 of monkey striate cortex. The Journal of Neuroscience. Mar 1995. 15. 3 Pt 1. 1808–18. 7891136. 10.1523/JNEUROSCI.15-03-01808.1995. 6578154. free.
  59. Gegenfurtner. Karl R.. Sensory systems: Cortical mechanisms of colour vision. Nature Reviews Neuroscience. 2003. 4. 7. 563–572. 10.1038/nrn1138. 12838331. 11505913 .
  60. Zeki. S. The Ferrier Lecture 1995 behind the seen: the functional specialization of the brain in space and time. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. Jun 29, 2005. 360. 1458. 1145–83. 10.1098/rstb.2005.1666. 16147515. 1609195.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Visual modularity".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.