Hymavathy Balasubramanian: Characterizing the physiological and functional response properties of the mouse superior colliculus

BCCN Berlin / Charité Universitätsmedizin Berlin & Technische Universität Berlin

 

Abstract

 

The variety of retinal ganglion cells (RGC) in the mouse eye suggests that vision is encoded with up to 30-42 different parallel streams of information. The mouse superior colliculus (SC) receives up to 90% of RGC’s axons, while only ~30% of them project to the lateral geniculate nucleus (LGN). Recently it was shown that the functional diversity in the LGN can be explained by a combination of few RGC response types. However, the extent of retinal convergence leading to the corresponding diversity in the SC remains under-examined. To address this question, in this thesis, data from extracellular recordings performed using Neuropixel probes with a tangential implantation in the mouse SC was analyzed. With a combination of a waveform feature based classifier, functional feature classification and linear decomposition techniques, we studied the retinocollicular connectivity in two ways – the effective number of retinal inputs that each SC neuron receives and its extent of retinal convergence. For the former, we identified that each SC neuron, on average, could receive inputs from about ~3.7 RGC axons. For the latter, we found that each SC neuron receives input from an average ~6 RGC classes of which ~2 that are functionally relevant. Taken together, we present preliminary results supporting that, like the dLGN, the SC also receives input from diverse retinal classes but with sparse convergence.

 

Additional Information

Master Thesis Defense

 

Organized by

Dr. Jens Kremkow   & Prof. Klaus Obermayer   / Lisa Velenosi