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Mechanisms underlying contrast-dependent orientation selectivity in mouse V1.

Wei P Dai^1,2, Douglas Zhou^3,4,5, David W McLaughlin^6,7,8,9,10

¹School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.

Proceedings of the National Academy of Sciences of the United States of America

|October 20, 2018

Summary

Mouse primary visual cortex (V1) exhibits contrast-dependent orientation selectivity (OS) sharpening in excitatory neurons and broadening in inhibitory neurons. Computational models reveal feedback inhibition and preferential excitation as key mechanisms driving these distinct OS changes.

Keywords:

contrast dependence contrast invariance orientation selectivity

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Area of Science:

Computational Neuroscience
Systems Neuroscience
Visual Processing

Background:

Mouse primary visual cortex (V1) exhibits distinct response properties compared to cats and monkeys.
Contrast invariance in orientation selectivity (OS) observed in cats/monkeys is replaced by contrast-dependent OS sharpening (excitatory) and broadening (inhibitory) in mice.

Purpose of the Study:

To develop a large-scale computational model of the mouse V1 input layer.
To reproduce experimentally observed response properties, including contrast-dependent OS.
To elucidate the circuit mechanisms underlying contrast-dependent OS in mouse V1.

Main Methods:

Development of a large-scale computational model of mouse V1 input layer.
Constraining the model with experimental data on neuronal firing rates and OS.
Analyzing model dynamics to identify key circuit mechanisms.

Main Results:

The model successfully reproduces mouse V1 response properties, including contrast-dependent OS.
Strong feedback inhibition and orientation-preferential cortical excitation drive OS sharpening in excitatory neurons.
Non-preferential cortical excitation of inhibitory neurons leads to OS broadening, enhancing excitatory neuron OS.

Conclusions:

Feedback inhibition and specific cortical excitation patterns are crucial for mouse V1's contrast-dependent OS.
The balance of these mechanisms can be modulated to achieve contrast invariance.
Findings offer insights for future research on visual processing and circuit design.