Frequency selectivity of echo responses in the mouse primary auditory cortex

Meng Wang,Jianxiong Zhang,Xiang Liao,Ruijie Li,Xiaowei Chen,Jingcheng Li,Shaoqun Zeng

doi:10.1038/s41598-017-18465-w

Abstract

In the primary auditory cortex (A1), neuronal ensembles are activated relative to anticipated sound events following rhythmic stimulation, but whether the echo responses of the neurons are related to their frequency selectivity remains unknown. Therefore, we used in vivo two-photon Ca2+ imaging to record the neuronal activities in the mouse A1 to elucidate the relationship between their echo responses and frequency selectivity. We confirmed the presence of echo responses in a subgroup of mouse Layer 2/3 A1 neurons following a train of rhythmic pure tone stimulation. After testing with a range of frequencies, we found that these echo responses occurred preferentially close to the best frequencies of the neurons. The local organization of the echo responses of the neurons was heterogeneous in the A1. Therefore, these results indicate that the observed echo responses of neurons within A1 are highly related to their frequency selectivity.

Highlights

When humans and other animals interact with the natural environment, the use of sensory cues and previous experience are critical to form predictions that guide behavior and survival in the world[1,2]
Similar to broadband noise stimulation, as reported previously[5], following a train of rhythmic pure tone stimulation, we found that a subgroup of mouse Layer 2/3 (L2/3) auditory cortex neurons showed one or multiple times of the echo responses at the anticipated time interval in the absence of sound
We performed a post hoc histological experiment with a retrograde neuronal tracer, cholera toxin subunit B (CTB), which was injected into the imaged area (Fig. 1d) and we found retrogradely-labeled cortical projecting neurons mainly located in the ventral part of the lateral medial geniculate body (MGBv) (Fig. 1e), confirming that the recorded cortical site was located on the A1

Summary

Introduction

When humans and other animals interact with the natural environment, the use of sensory cues and previous experience are critical to form predictions that guide behavior and survival in the world[1,2]. By elucidating the response properties of neurons to sound frequencies in a small brain region, the local populations in the A1 are revealed to be highly heterogeneous, which means that neighboring neurons may present similar or extraordinarily different frequency tunings properties[21,22] These studies demonstrate that a rough tonotopic organization emerges at large scales, but local heterogeneity emerges at fine scales (

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Conclusion