Department of Neurobiology, University of California at Los Angeles
Ganglion Cell Responses Do Not Cluster in the Mouse Retina
It is well-known that different retinal ganglion cells respond differently to the same stimulus. For example, when presented with a step increase in light intensity, some cells respond to the onset of the step increase (ON cells), some to the offset (OFF cells) and some to both (ON-OFF cells). Similarly, when presented with moving gratings, some cells show a selectivity to the direction of motion, whereas others do not. These and other differences have led to the widely-accepted view that ganglion cell responses fall into discrete groups. Here we examined the distribution of mouse ganglion cell responses when presented with three stimuli: illumination only in the center of the receptive field, full field illumination, and moving gratings. We collected a large data set of over 300 cells with multi-electrode recording. We found that ganglion cell responses did not cluster into discrete groups, but rather formed a continuous distribution. While ON, OFF and ON-OFF responses were observed, there was no clear division among them. This result held for center-only illumination, full field illumination and moving gratings. In addition, while we were able to detect directionally selective cells, there was no clustering of responses into groups based on this parameter, either. We speculate that this result is not unique to the mouse, but will generalize to other, more well-characterized systems when large data sets are considered.