Koniocellular cell

In neuroscience, koniocellular cells, also called K-cells, are relatively small neurons located in the koniocellular layer of the lateral geniculate nucleus (LGN) within the thalamus of primates, including humans.

Even if the quantity of neurons is approximately equal to the number of magnocellular cells, the koniocellular layers are much thinner due to their size.

Koniocellular cells are a heterogeneous population differing in many aspects, such as response properties and connectivity.

Experimental results suggest that K cells could contribute to aspects of spatial and temporal vision, but it is unclear exactly how.

Larger subpopulations form bridges spanning the distance between two adjacent K layers.

Retinogeniculate axons terminating in the middle K layers display center-only blue-ON/yellow-OFF receptive fields.

Thus, it is assumed that the K layers are functionally related to the superior colliculus, e.g. reflexive control of eye movements.

[1]: 144  Throughout each K layer there are neurons that innervate the extrastriate cortex and are likely to sustain some visual behaviors in the absence of V1.

[1]: 134  While M and P layers in LGN and their axonal terminations in V1 degenerate after a loss of patterned visual input, K cells are not affected.

In case of V1 lesions, additional LGN inactivation leads to a strong reduction of neural activity in the extrastriate areas, such as MT.

[5] Research has shown that there exists a direct pathway from the LGN to MT consisting mostly of koniocellular cells.

These results suggest that the koniocellular layers play a key role in V1-independent vision.

This direct connection from the LGN, more precisely the koniocellular layers, to MT could account for the phenomenon of blindsight as well as for rapid detection of moving objects in healthy subjects.