The mitochondria in all living cells except bone and hair contain an enzyme called cytochrome oxidase. It is possible to stain brain cells so that various concentrations of cytochrome oxidase can be identified. The original cytochrome oxidase observations were made by Wong-Riley in 1979. More recently Livingstone and Hubel (1984, 1988) have exploited the technique and made a number of interesting observations.

Cortical areas with high concentrations of cytochrome oxidase were named "blobs" by Livingstone and Hubel. In macaque monkeys it would appear that a great deal of color information is processed in the blob areas and in areas of low concentration little color information is processed. The other thing of note is that little or no orientation specificity is exhibited in the blobs but orientation specificity is evident in areas of low concentration.

Unfortunately, the scientific waters are a bit muddied with the following observation. It would appear that retinas of nocturnal monkeys with very little color vision exhibit blobs indicating a richness of cytochrome oxidase. We will have to wait for future research to obtain a more complete understanding of the role played by cortical areas exhibiting blobs.

LGN and Cortex
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