Striatal direct pathway neurons play leading roles in accelerating rotarod motor skill learning

Summary

Dorsal striatum is important for movement control and motor skill learning. However, it remains unclear how the spatially and temporally distributed striatal medium spiny neuron (MSN) activity in the direct and indirect pathways (D1 and D2 MSNs, respectively) encodes motor skill learning. Combining miniature fluorescence microscopy with an accelerating rotarod procedure, we identified two distinct MSN subpopulations involved in accelerating rotarod learning. In both D1 and D2 MSNs, we observed neurons that displayed activity tuned to acceleration during early stages of trials, as well as movement speed during late stages of trials. We found a distinct evolution trajectory for early-stage neurons during motor skill learning, with the evolution of D1 MSNs correlating strongly with performance improvement. Importantly, optogenetic inhibition of the early-stage neural activity in D1 MSNs, but not D2 MSNs, impaired accelerating rotarod learning. Together, this study provides insight into striatal D1 and D2 MSNs encoding motor skill learning.

Graphical abstract

Highlights

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  Distinct subsets of D1 and D2 MSNs correlate with different behavioral variables

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  Intratrial early-stage D1 MSNs correlates with rotarod motor skill learning

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  Speed coding in dorsal striatum is stable across rotarod training

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  Optogenetic inhibition of early-stage D1 MSNs impairs rotarod motor skill learning

Abstract

Biological sciences; Neuroscience; Sensory neuroscience