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bioRxiv · 10.1101/2024.07.03.601922

Retinal bipolar cells borrow excitability from electrically coupled inhibitory interneurons to amplify excitatory synaptic transmission

Yadav, S. C.·Ganzen, L.·Nawy, S.·Kramer, R. H.
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Abstract

Bipolar cells (BCs) carry visual information from photoreceptors in the outer retina to retinal ganglion cells (RGCs) in the inner retina. Most BCs lack voltage-gated Na+ (NaV) channels and action potentials. Instead, voltage signals spread passively from input to output synapses. Despite this, we find that blocking NaV channels reduces synaptic output of On-cone bipolar cells (On-CBCs). These cells borrow NaV channel-mediated excitability from electrically coupled A2 amacrine cells to amplify excitatory output, allowing voltage changes to be transmitted more effectively to downstream RGCs in dim light. Because neighboring On-CBCs form electrical synapses onto the same A2 cell, a spatially adjacent group of On-CBCs is more effective than a dispersed set for recruiting A2 cell electrical excitability and driving post-synaptic RGCs. This mechanism filters the neural representation of an image to highlight shapes over spatially uncorrelated stimuli, a sophisticated feature detection property that is well-suited for object recognition.

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Yadav, S. C., Ganzen, L., Nawy, S., Kramer, R. H.. 2024-07-05. Retinal bipolar cells borrow excitability from electrically coupled inhibitory interneurons to amplify excitatory synaptic transmission. https://doi.org/10.1101/2024.07.03.601922

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