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Updated: Jun 6, 2026

Electrophysiological Investigations of Retinogeniculate and Corticogeniculate Synapse Function
Published on: August 7, 2019
Asymmetric inhibitory connections enhance directional selectivity in a three-layer simulation model of retinal
Amane Koizumi1, Misako Takayasu, Hideki Takayasu
1Division of Correlative Physiology, National Institute for Physiological Sciences, Okazaki, Japan. amane@nips.ac.jp
Abstract:
In this paper, we found that spatial and temporal asymmetricity of excitatory connections are able to generate directional selectivity which can be enhanced by asymmetrical inhibitory connections by reconstructing a hexagonally-arranged three-layered simulation model of retina by NEURON simulator. Asymmetric excitatory inputs to ganglion cells with randomly arborizing dendrites were able to generate weaker directional selectivity to moving stimuli whose speed was less than 10 μm/msec. By just adding asymmetric inhibitory connections via inhibitory amacrine cells, directional selectivity became stronger to respond to moving stimuli at ten times faster speed (< 100 μm/msec). In conclusion, an excitatory mechanism appeared to generate directional selectivity while asymmetric inhibitory connections enhance directional selectivity in retina.
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