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Monosynaptic trans-collicular pathways link mouse whisker circuits to integrate somatosensory and motor cortical signals.

Authors :
Martín-Cortecero J
Isaías-Camacho EU
Boztepe B
Ziegler K
Mease RA
Groh A
Source :
PLoS biology [PLoS Biol] 2023 May 19; Vol. 21 (5), pp. e3002126. Date of Electronic Publication: 2023 May 19 (Print Publication: 2023).
Publication Year :
2023

Abstract

The superior colliculus (SC), a conserved midbrain node with extensive long-range connectivity throughout the brain, is a key structure for innate behaviors. Descending cortical pathways are increasingly recognized as central control points for SC-mediated behaviors, but how cortico-collicular pathways coordinate SC activity at the cellular level is poorly understood. Moreover, despite the known role of the SC as a multisensory integrator, the involvement of the SC in the somatosensory system is largely unexplored in comparison to its involvement in the visual and auditory systems. Here, we mapped the connectivity of the whisker-sensitive region of the SC in mice with trans-synaptic and intersectional tracing tools and in vivo electrophysiology. The results reveal a novel trans-collicular connectivity motif in which neurons in motor- and somatosensory cortices impinge onto the brainstem-SC-brainstem sensory-motor arc and onto SC-midbrain output pathways via only one synapse in the SC. Intersectional approaches and optogenetically assisted connectivity quantifications in vivo reveal convergence of motor and somatosensory cortical input on individual SC neurons, providing a new framework for sensory-motor integration in the SC. More than a third of the cortical recipient neurons in the whisker SC are GABAergic neurons, which include a hitherto unknown population of GABAergic projection neurons targeting thalamic nuclei and the zona incerta. These results pinpoint a whisker region in the SC of mice as a node for the integration of somatosensory and motor cortical signals via parallel excitatory and inhibitory trans-collicular pathways, which link cortical and subcortical whisker circuits for somato-motor integration.<br />Competing Interests: The authors have declared that no competing interests exist.<br /> (Copyright: © 2023 Martín-Cortecero et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Details

Language :
English
ISSN :
1545-7885
Volume :
21
Issue :
5
Database :
MEDLINE
Journal :
PLoS biology
Publication Type :
Academic Journal
Accession number :
37205722
Full Text :
https://doi.org/10.1371/journal.pbio.3002126