Ocular dominance column

rdf:langString Ocular dominance column

rdf:langString note

rdf:langString Ocular dominance columns are stripes of neurons in the visual cortex of certain mammals (including humans) that respond preferentially to input from one eye or the other. The columns span multiple cortical layers, and are laid out in a striped pattern across the surface of the striate cortex (V1). The stripes lie perpendicular to the orientation columns. Ocular dominance columns were important in early studies of cortical plasticity, as it was found that monocular deprivation causes the columns to degrade, with the non-deprived eye assuming control of more of the cortical cells. It is believed that ocular dominance columns must be important in binocular vision. Surprisingly, however, many squirrel monkeys either lack or partially lack ocular dominance columns, which would not be expected if they are useful. This has led some to question whether they serve a purpose, or are just a byproduct of development.

rdf:langString ref|A very good analogy for this is the idea of coloring a map. Just like a map of Asia could be colored by religion or by language, the columns are not physical things but regions defined by shared attributes. Also much like a map of religion the borders tend to be fuzzy with no clear distinction between one area and the next columns often don't have sharp borders. Similarly, there may be overlap, just as people at the border between France and Germany are a mixture of French speakers, German speakers, or bilingual. There are even occasional neurons belonging to the ipsilateral eye in a contralateral column just like the occasional Portuguese speaker may be found in China. It was once believed the columns were discrete units with sharp borders but the idea of fuzzy, mostly continuous regions is now preferred.|name=mapanalogy|group="note"