Whole-brain connectivity atlas of glutamatergic and GABAergic neurons in the mouse dorsal and median raphe nuclei.

Zhengchao Xu,Qingtao Sun,Anan Li,Zhao Feng,Wu Chen,Qingming Luo,Xiangning Li,Lei Deng,Ayizuohere Tudi,Xueyan Jia,Jing Yuan,Mengting Zhao,Pan Luo,Hui Gong,Tao Jiang

doi:10.7554/elife.65502

Abstract

The dorsal raphe nucleus (DR) and median raphe nucleus (MR) contain populations of glutamatergic and GABAergic neurons that regulate diverse behavioral functions. However, their whole-brain input-output circuits remain incompletely elucidated. We used viral tracing combined with fluorescence micro-optical sectioning tomography to generate a comprehensive whole-brain atlas of inputs and outputs of glutamatergic and GABAergic neurons in the DR and MR. We found that these neurons received inputs from similar upstream brain regions. The glutamatergic and GABAergic neurons in the same raphe nucleus had divergent projection patterns with differences in critical brain regions. Specifically, MR glutamatergic neurons projected to the lateral habenula through multiple pathways. Correlation and cluster analysis revealed that glutamatergic and GABAergic neurons in the same raphe nucleus received heterogeneous inputs and sent different collateral projections. This connectivity atlas further elucidates the anatomical architecture of the raphe nuclei, which could facilitate better understanding of their behavioral functions.

Highlights

The dorsal raphe nucleus (DR) and median raphe nucleus (MR, equivalent to the superior central nucleus raphe in the Allen Mouse Brain Common Coordinate Framework version 3 (AllenCCFv3)) belong to the rostral group of the raphe nuclei and contain most of brain’s serotonergic neurons (Wang et al, 2020; Watson, et al, 2012)
We found that these neurons received inputs from similar upstream brain regions
Given that numerous Vglut3+ neurons in the DR and MR are serotonergic (Huang et al, 2019; Pinto et al, 2019; Sos et al, 2017), while Vglut2+ neurons in the DR and MR were distinct from the serotonergic neurons (Huang et al, 2019; Szőnyi et al, 2019), the present study focused on the connectivity of Vglut2+ neurons in the DR and MR

Summary

Introduction

The dorsal raphe nucleus (DR) and median raphe nucleus Previous studies have revealed that the DR and MR integrate massive inputs from and send outputs to vast brain regions in the forebrain and midbrain (Marcinkiewicz et al, 1989; Oh, et al., 2014; Peyron et al, 1997; Vertes et al, 2008) These studies were unable to elucidate the neural connections of specific neuron types. We implemented a pipeline composed of viral tracing, whole-brain high-resolution imaging, data processing and analysis to dissect whole-brain inputs and outputs of glutamatergic and GABAergic neurons in the DR and MR and understand their organizational principle. We identified the long-range input/output circuits, quantified the wholebrain distribution, analyzed the whole-brain connectivity pattern, and generated a precise wholebrain atlas of inputs and outputs of glutamatergic and GABAergic neurons in the DR and MR, which could facilitate the understanding of their functional differences and provide anatomical foundations for investigating into their functions. We developed the interactive website (http://atlas.brainsmatics.org/a/xu2011) to better present and share the raw data and results

Results

Discussion

Materials and Methods

594 References