A hypothetical rivalry in retina and some spike sorting progress

Kevin Sean Chen — Mon, 05 Jan 2015 17:28:22 +0000

As observed in my experiments, "achromatic" receptive fields may react similarly to blue or green light stimuli, which are the two observable colors in bullfrogs. However, under intermeshed blue and green light stimulus, we constantly (such experiment had been repeated for more than five times) see the activity of recorded ganglion cells synchronize to only one color. I suspect that the retina randomly "follow" a color, since the same retina could produce activity following blue or green light under a same stimulus, and uninfluenced by the starting color.

Turning to a theoretical view, I want to build an analogy from “binocular rivalry”, a well-known phenomenon in psychophysics. I borrowed a simple model for binocular rivalry from a reference. By tuning the time scale and increasing the mutual inhibition strength, the activities of two pathways show similar patterns from the experiment. Therefore, I’d like to claim that maybe such rivalry observed in the retina is due to simple inhibition between two parallel dichromatic processes, and this relation might even contribute to monocular rivalry observed in psychophysical experiments (as shown in the figure).

In Addition, I’m trying to perform spike sorting recently. I’m now able to sort different cell types by Offline Sorter, plot the spike trigger average and raster plots for each cells with Matlab, and also perform some simple clustering (However, I'm still looking for the criteria and methods to define different waveforms. There's a reference dicussing about it). In the future, I hope to map the physical positions back to where the cell locates on the MEA, and we’re also willing to calculate the receptive fields for further experiments on the interesting spatial dynamics in retina.

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retina

binocular rivalry

spike sorting

group meeting

Laboratory of Computing Biological Networks - spike sorting

A hypothetical rivalry in retina and some spike sorting progress