Ocular dominance column

Ocular dominance columns are stripes of neurons in the visual cortex of certain mammals (including humans[1]) that respond preferentially to input from one eye or the other.

[2] The columns span multiple cortical layers, and are laid out in a striped pattern across the surface of the striate cortex (V1).

[4] Ocular dominance columns were discovered in the 1960s by Hubel and Wiesel as part of their Nobel Prize winning work on the structure of the visual cortex in cats.

[4][7] The columns are innervated by input from the lateral geniculate nucleus (LGN) into cortical layer 4 and have mostly reciprocal projections to many other parts of the visual cortex.

[8] The ocular dominance columns cover the primary (striate) visual cortex, with the exception of monocular regions of the cortical map corresponding to peripheral vision and the blind spot.

However, the same region of cortex could also be colored by the direction of edge that it responds to, resulting in the orientation columns, which are laid out in a characteristic pinwheel shape.

[11] Similarly, the correlated activation for the retinal waves may direct development of the ocular dominance columns, which receive input from the LGN.

One major model of the formation of the stripes seen in ocular dominance columns is that they form by Hebbian competition between axon terminals.

[21] This basic model has since been extended to be more physiologically plausible with the addition of long term potentiation and depression, synaptic normalization,[23] neurotrophin release,[24] reuptake,[25] and spike-timing-dependent plasticity.

[26] Chemotactic models posit the existence of axon guidance molecules that direct the initial formation of the ocular dominance columns.

Furthermore, work in achiasmatic[note 6] Belgian sheepdogs has shown that columns can form between the projections from the temporal and nasal retina of the same eye, clearly suggesting a nasal-temporal labeling, rather than contralateral vs. ipsilateral, which would be much easier to explain with activity dependent mechanisms.

A simulation of the ocular dominance column pattern , as might be seen if the surface of V1 were colored according to eye preference.
A typical map of the relationship between ocular dominance, orientation , and cytochrome oxidase . Dark and light areas represent neurons that respond preferentially to the left and right eye. Colors represent orientation selectivity [ note 1 ] of the neurons. Areas outlined in white have high levels of cytochrome oxidase (function not yet established). [ 4 ] Notice that the centers of orientation " pinwheels " and cytochrome oxidase blobs both tend to be in line with the centers of the ocular dominance columns, but there is no obvious relation between orientation and cytochrome oxidase.