blob (visual system)

Blobs are sections of primary visual cortex (V1) above and below layer IV where groups of neurons sensitive to color assemble in cylindrical shapes. They were first identified in 1979 by Margaret Wong-Riley in cats when she used a cytochrome oxidase stain, from which they get their name.{{cite journal|last=Wong-Riley|first=Margaret|date=July 27, 1979|title=Changes in the visual system of monocularly sutured or enucleated cats demonstrable with cytochrome oxidase histochemistry|journal=Brain Research|volume=171|issue=1|pages=11–28|pmid=223730|doi=10.1016/0006-8993(79)90728-5|s2cid=20990578 }} These areas receive input from koniocellular cells in the dorsal lateral geniculate nucleus dLGN and output to the thin stripes of area V2. Interblobs are areas between blobs that receive the same input, but are sensitive to orientation instead of color. They output to the pale and thick stripes of area V2.

Blobs are on the koniocellular pathway. This pathway begins at the photoreceptors which then relay signals to the 'K' ganglion cells in the retina. The pathway then continues out of the eye to the layers in-between the parvocellular and magnocellular layers of the dLGN. This pathway then terminates at the blobs in V1.{{cite journal |last1=Rockland |first1=Kathleen S. |title=Cytochrome oxidase "blobs": a call for more anatomy |journal=Brain Structure and Function |date=2021 |volume=226 |issue=9 |pages=2793–2806 |doi=10.1007/s00429-021-02360-2 |pmid=34382115 |pmc=8778949 }} Lesioning of the koniocellular pathway leads to lack of acuity in shapes and colour.