Control of Orienting Movements and Locomotion by Projection-Defined Subsets of Brainstem V2a Neurons

Usseglio, Giovanni; Gatier, Edwin; Heuzé, Aurélie; Hérent, Coralie; Bouvier, Julien

doi:10.1016/j.cub.2020.09.014

Cited by 68 publications

(122 citation statements)

References 77 publications

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“…Our observations support the idea that distinct reticulospinal neurons control speed and turning/braking movements [29, 30, 31]. First, our data indicate that a substrate for turning movements is activated transiently during MLR stimulation when approaching a corner.…”

Section: Discussionsupporting

confidence: 88%

“…First, our data indicate that a substrate for turning movements is activated transiently during MLR stimulation when approaching a corner. This motor signature closely matches that previously recorded when selectively activating the brainstem circuit for turning [30, 31]. Indeed, unilateral activation of Chx10-positive reticulospinal neurons in the Gi produces an ipsilateral turn together with a decrease in speed [30, 31].…”

Section: Discussionsupporting

confidence: 82%

“…This motor signature closely matches that previously recorded when selectively activating the brainstem circuit for turning [30, 31]. Indeed, unilateral activation of Chx10-positive reticulospinal neurons in the Gi produces an ipsilateral turn together with a decrease in speed [30, 31]. Gi-Chx10 reticulospinal neurons receive no input from the MLR, but a major input from the contralateral superior colliculus (SC), a region involved in visuomotor transformations [30].…”

Section: Discussionsupporting

confidence: 77%

“…7). Altogether, this suggests that the brainstem substrates for braking and turning ([29, 30, 31], see also [57]) can be recruited during MLR stimulation, therefore allowing the animal to smoothly navigate the environment (Fig. 7).…”

Section: Discussionmentioning

confidence: 99%

“…In mammals, steering commands are relayed by reticulospinal neurons in the gigantocellular nucleus ( Gi ) that express the molecular marker Chx10. Their unilateral activation evokes ipsilateral braking and turning [29, 30, 31]. These neurons receive no input from the MLR, but a major glutamatergic input from the contralateral superior colliculus ( SC ), a region involved in visuomotor transformations ([32, 33, 34], for review [35]).…”

Section: Introductionmentioning

confidence: 99%

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Freely behaving mice can brake and turn during optogenetic stimulation of the Mesencephalic Locomotor Region

Zouwen

Boutin

Fougère

et al. 2020

Preprint

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Background: Stimulation of the Mesencephalic Locomotor Region (MLR) is increasingly considered as a target to improve locomotor function in Parkinson's disease and spinal cord injury. A key function of the MLR is to control the speed of forward symmetrical locomotor movements. However, the ability of freely moving mammals to integrate environmental cues to brake and turn during MLR stimulation is poorly documented. Objective/hypothesis: We investigated whether freely behaving mice could brake or turn based on environmental cues during MLR stimulation. Methods: We stimulated the cuneiform nucleus in mice expressing channelrhodopsin in Vglut2-positive neurons in a Cre-dependent manner (Vglut2-ChR2-EYFP) using optogenetics. We detected locomotor movements using deep learning. We used patch-clamp recordings to validate the functional expression of channelrhodopsin and neuroanatomy to visualize the stimulation sites. Results: Optogenetic stimulation of the MLR evoked locomotion and increasing laser power increased locomotor speed. Gait diagram and limb kinematics were similar during spontaneous and optogenetic-evoked locomotion. Mice could brake and make sharp turns (~90⁰) when approaching a corner during MLR stimulation in an open-field arena. The speed during the turn was scaled with the speed before the turn, and with the turning angle. In a reporter mouse, many Vglut2-ZsGreen neurons were immunopositive for glutamate in the MLR. Patch-clamp recordings in Vglut2-ChR2-EYFP mice show that blue light evoked short latency spiking in MLR neurons. Conclusion: MLR glutamatergic neurons are a relevant target to improve locomotor activity without impeding the ability to brake and turn when approaching an obstacle, thus ensuring smooth and adaptable navigation.

show abstract

Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 82%

Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Freely behaving mice can brake and turn during optogenetic stimulation of the Mesencephalic Locomotor Region

Zouwen

Boutin

Fougère

et al. 2020

Preprint

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From retina to motoneurons: A substrate for visuomotor transformation in salamanders

Flaive

Ryczko

2022

J of Comparative Neurology

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The transformation of visual input into motor output is essential to approach a target or avoid a predator. In salamanders, visually guided orientation behaviors have been extensively studied during prey capture. However, the neural circuitry involved is not resolved. Using salamander brain preparations, calcium imaging and tracing experiments, we describe a neural substrate through which retinal input is transformed into spinal motor output. We found that retina stimulation evoked responses in reticulospinal neurons of the middle reticular nucleus, known to control steering movements in salamanders. Microinjection of glutamatergic antagonists in the optic tectum (superior colliculus in mammals) decreased the reticulospinal responses. Using tracing, we found that retina projected to the dorsal layers of the contralateral tectum, where the dendrites of neurons projecting to the middle reticular nucleus were located.In slices, stimulation of the tectal dorsal layers evoked glutamatergic responses in deep tectal neurons retrogradely labeled from the middle reticular nucleus. We then examined how tectum activation translated into spinal motor output. Tectum stimulation evoked motoneuronal responses, which were decreased by microinjections of glutamatergic antagonists in the contralateral middle reticular nucleus. Reticulospinal fibers anterogradely labeled from tracer injection in the middle reticular nucleus were preferentially distributed in proximity with the dendrites of ipsilateral motoneurons. Our work establishes a neural substrate linking visual and motor centers in salamanders. This retino-tecto-reticulo-spinal circuitry is well positioned to control orienting behaviors. Our study bridges the gap between the behavioral studies and the neural mechanisms involved in the transformation of visual input into motor output in salamanders.

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From the eye to the wing: neural circuits for transforming optic flow into motor output in avian flight

2023

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Control of Orienting Movements and Locomotion by Projection-Defined Subsets of Brainstem V2a Neurons

Cited by 68 publications

References 77 publications

Freely behaving mice can brake and turn during optogenetic stimulation of the Mesencephalic Locomotor Region

Freely behaving mice can brake and turn during optogenetic stimulation of the Mesencephalic Locomotor Region

From retina to motoneurons: A substrate for visuomotor transformation in salamanders

From the eye to the wing: neural circuits for transforming optic flow into motor output in avian flight

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