Abstract
A series of recent studies identified key structures in the mesencephalic locomotor region and the caudal brainstem of mice involved in the initiation and control of slow (exploratory) and fast (escape-type) locomotion and gait. However, the interactions of these brainstem centers with each other and with the spinal locomotor circuits are poorly understood. Previously we suggested that commissural and long propriospinal interneurons are the main targets for brainstem inputs adjusting gait (Danner et al., 2017). Here, by extending our previous model, we propose a connectome of the brainstem-spinal circuitry and suggest a mechanistic explanation of the operation of brainstem structures and their roles in controlling speed and gait. We suggest that brainstem control of locomotion is mediated by two pathways, one controlling locomotor speed via connections to rhythm generating circuits in the spinal cord and the other providing gait control by targeting commissural and long propriospinal interneurons.
Highlights
To survive in changing and unpredictable environments animals need to continuously adapt their behavior including locomotor speed
To model and computationally investigate the brainstem control of locomotion, we built upon our previous model of spinal circuits, consisting of four rhythm generating circuits (RGs), which interact via local cervical and lumbar commissural interneurons (CINs) and long propriospinal neurons (LPNs) connecting cervical and lumbar compartments (Danner et al, 2017)
The control of locomotor frequency and gaits was provided by changes of tonic excitatory inputs to the RGs and inhibitory inputs to the particular spinal CIN and LPN
Summary
To survive in changing and unpredictable environments animals need to continuously adapt their behavior including locomotor speed. The generation of locomotor oscillations and mutual interactions between oscillators controlling each limb are implemented within the spinal cord (Grillner, 2006; Kiehn, 2006; Goulding, 2009; Grillner and Jessell, 2009; Kiehn, 2016; Boije and Kullander, 2018), both locomotor speed and interlimb coordination (gait) are controlled by several brainstem structures that transform signals from higher brain centers into meaningful commands to initiate, stop or modulate locomotor frequency and gait (Lemon, 2008; Ryczko and Dubuc, 2013; Roseberry et al, 2016; Kim et al, 2017; Takakusaki, 2017; Brownstone and Chopek, 2018; Ferreira-Pinto et al, 2018; Gatto and Goulding, 2018).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
