Control of response reliability by parvalbumin-expressing interneurons in visual cortex.

Yingjie Zhu,Kefei Liu,Wenhui Qiao,Huiyuan Zhong,Haishan Yao

doi:10.1038/ncomms7802

Abstract

The responses of visual cortical neurons to natural stimuli are both reliable and sparse. These properties require inhibition, yet the contribution of specific types of inhibitory neurons is not well understood. Here we demonstrate that optogenetic suppression of parvalbumin (PV)- but not somatostatin (SOM)-expressing interneurons reduces response reliability in the primary visual cortex of anaesthetized and awake mice. PV suppression leads to increases in the low firing rates and decreases in the high firing rates of cortical neurons, resulting in an overall reduction of the signal-to-noise ratio (SNR). In contrast, SOM suppression generally increases the overall firing rate for most neurons, without affecting the SNR. Further analysis reveals that PV, but not SOM, suppression impairs neural discrimination of natural stimuli. Together, these results reveal a critical role for PV interneurons in the formation of reliable visual cortical representations of natural stimuli.

Highlights

The responses of visual cortical neurons to natural stimuli are both reliable and sparse
As anaesthesia can affect the activity of inhibitory neurons[20], we examined the effect of optogenetic stimulation in awake, head-fixed mice (Fig. 2d, a putative excitatory cell)
The correlation between decrease in CC and decrease in signal-to-noise ratio (SNR) was weak but significant (r 1⁄4 0.17, P 1⁄4 0.03, n 1⁄4 126). These results indicated that the decrease in response reliability and SNR during PV suppression could be attributed to the decrease in high-rate neuronal response

Summary

Introduction

The responses of visual cortical neurons to natural stimuli are both reliable and sparse. Further analysis reveals that PV, but not SOM, suppression impairs neural discrimination of natural stimuli Together, these results reveal a critical role for PV interneurons in the formation of reliable visual cortical representations of natural stimuli. We use multi-electrode recording in mouse V1 to measure cortical neural responses to repeated presentations of movies with natural scenes, with and without optogenetic suppression of PV or SOM interneurons. In both anaesthetized and awake mice, we find that only PV suppression results in reduced response reliability and SNR of V1 neurons. Our results demonstrate that PV interneurons critically contribute to the response reliability and visual coding of cortical neurons

Methods

Results

Conclusion