Ocular dominance column

Critical periods are those in which the synaptic circuitry of a given brain region becomes stabilized in a functionally optimized conformation. The cerebral cortex and other brain structures contain functional maps for the activities characteristic of a species. The best example is the ocular dominance columns and other physical and functional characteristics of the circuitry within the visual cortical system that process information derived from the left and right visual fields, producing a map of the visual world. Other internal maps exist for the body (somatosensory, motor corti-... 

Growley, J.C., and Kats, L.G. (2000) Early development of ocular dominance columns. Science 290 1321-1324. 

The width of an ocular dominance column is approximately 0.4 mm (Hubei and Wiesel 1977). Two such columns containing the data for both eyes amount to roughly 1 mm. The orientation-selective cells are not arranged randomly. If a penetration is made horizontally to the cortical surface, recording the response of the cells, it is found that the optimal or preferred orientation to which the cell responds changes continuously. Roughly, a 1-mm displacement corresponds to a 180° change in orientation. In other words, a 2 x 2 mm2... 

Bartfeld E, Grinvald A. 1992. Relationships between orientation-preference pinwheels, cytochrome oxidase blobs, and ocular-dominance columns in primate striate cortex. Proc Natl Acad Sci USA 89(24) 11905-11909. 

Cabelli, R.J., Hohn, A. and Shatz, C.J. (1995) Inhibition of ocular dominance column formation by infusion of NT-4/5 or BDNF. Science 267 1662-1666. 

The topography of orientation-specific cells and of ocular dominance columns is remarkably uniform throughout VI, which is surprising because the receptive fields near the fovea are 10 to 30 times smaller than those at the periphery. This phenomenon is called magnification. The fovea maps to a greater relative distance on the surface of VI than does the peripheral retina, by as much as 36-fold [Daniel and Whitteridge, 1961]. In fact, the majority of VI processes only the central 10° of the visual field. Both simple and complex cells in the foveal portion can resolve bars as narrow as 2 min of arc. Toward the periphery, the resolution falls off to 1° of arc. 

Hubel, D. H., Wiesel, T. N., and Lam, D. M. K., 1974, Autoradiographic demonstration of ocular dominance columns in the monkey striate cortex by means of transneuronal transport, Brain Res. 79 273-279. 

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