The mesencephalic locomotor region recruits V2a reticulospinal neurons to drive forward locomotion in larval zebrafish.

ABSTRACT: The mesencephalic locomotor region (MLR) is a brain stem area whose stimulation triggers graded forward locomotion. How MLR neurons recruit downstream vsx2⁺ (V2a) reticulospinal neurons (RSNs) is poorly understood. Here, to overcome this challenge, we uncovered the locus of MLR in transparent larval zebrafish and show that the MLR locus is distinct from the nucleus of the medial longitudinal fasciculus. MLR stimulations reliably elicit forward locomotion of controlled duration and frequency. MLR neurons recruit V2a RSNs via projections onto somata in pontine and retropontine areas, and onto dendrites in the medulla. High-speed volumetric imaging of neuronal activity reveals that strongly MLR-coupled RSNs are active for steering or forward swimming, whereas weakly MLR-coupled med

SUBMITTER: Carbo-Tano M 

PROVIDER: S-EPMC10545542 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature