Abstract
Coordination of bilateral movements is essential for a large variety of animal behaviors. The olivocerebellar system is critical for the control of movement, but its role in bilateral coordination has yet to be elucidated. Here, we examined whether Purkinje cells encode and influence synchronicity of left-right whisker movements. We found that complex spike activity is correlated with a prominent left-right symmetry of spontaneous whisker movements within parts, but not all, of Crus1 and Crus2. Optogenetic stimulation of climbing fibers in the areas with high and low correlations resulted in symmetric and asymmetric whisker movements, respectively. Moreover, when simple spike frequency prior to the complex spike was higher, the complex spike-related symmetric whisker protractions were larger. This finding alludes to a role for rebound activity in the cerebellar nuclei, which indeed turned out to be enhanced during symmetric protractions. Tracer injections suggest that regions associated with symmetric whisker movements are anatomically connected to the contralateral cerebellar hemisphere. Together, these data point toward the existence of modules on both sides of the cerebellar cortex that can differentially promote or reduce the symmetry of left and right movements in a context-dependent fashion.
Highlights
A wide range of simple and complex behaviors, varying from eye movements to spatial navigation, require coordinated movements of the left and right side of the body
To assess whether and to what extent symmetric whisker movements during spontaneous behavior are correlated with activity in the olivocerebellar system, we recorded the complex spikes (CSs) activity from 127 single-unit Purkinje cells in lobules Crus[1] and Crus[2], which are known to encode whisker movements.[43]
When we plotted the left-right magnitudesquared coherence just before and after the onset of whisking epochs, we observed that the coherence was significantly higher (p < 0.001) for epochs associated with CSs than those without (Figures 1C and 1D)
Summary
A wide range of simple and complex behaviors, varying from eye movements to spatial navigation, require coordinated movements of the left and right side of the body. Locomotion or flying can only occur through a complex series of co-activations and alternations between sets of neurons and muscles on both sides of the body.[1] bilateral motor coordination is present and essential across the entire animal kingdom Rodents, such as mice and rats, exhibit a wide variety of coordinated bilateral motor behaviors, such as whisking, with flexible and adaptive levels of symmetry.[2,3,4,5] Whisking is instrumental for nocturnal rodents to navigate in near total darkness;[6] left and right whisker movements can occur at variable levels of symmetry and inform changes in head direction with respect to cues in the environment.[2] given the rhythmicity of whisker movements, which are at least in part generated by a central pattern generator located in the intermediate reticular formation, this behavior may be exploited to estimate the dynamic changes of head position over time.[3,7,8,9] Whisker movements are controlled by retractor and protractor motor neurons in the facial nucleus,[7,10,11] which receive input from a variety of structures in addition to the central pattern generator.[8,12,13,14] Yet how the symmetry of movements on both sides of the body can be precisely coordinated is largely unknown
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
