RETINAL GANGLION CELL INPUTS TO THE KONIOCELLULAR PATHWAY

Brett A. Szmajda, Ulrike Grünert, and Paul R. Martin

The koniocellular pathway is a poorly-understood part of the visual system. We studied the ganglion cell inputs to this pathway. Retinal ganglion cells were labeled by photofilling following injections of retrograde tracer in the lateral geniculate nucleus (LGN), or by intracellular injection with neurobiotin.
Small bistratified cells and large sparse cells were the most commonly labeled wide-field cells following LGN injections in koniocellular layer K3. This is consistent with physiological evidence that the role of this layer includes transmission of S-cone signals to the visual cortex. Other wide-field cell types were also labeled following injections including K3, and other koniocellular LGN layers; these cell types may correspond to "non-blue koniocellular" receptive fields recorded in physiological studies.

Figure: Morphological diversity of wide-field ganglion cells in primate retina. Clockwise from upper left: a giant sparse cell; an unclassified wide-field cell; a large sparse cell; a broad thorny cell. Inset (lower right) shows a midget cell from. Arrows indicate axons.

Reference: Szmajda BA, Grunert U, Martin PR (2008). Retinal ganglion cell inputs to the koniocellular pathway. Journal of Comparative Neurology 510: 251-268.