Shared Cortex-Cerebellum Dynamics in the Execution and Learning of a Motor Task

Area of Science:

• Neuroscience
• Systems Neuroscience
• Motor Control

Background:

• The mammalian neocortex, specifically layer 5 pyramidal (L5) cells, projects to cerebellar granule cells (GrCs) via the pons, forming a crucial neural pathway.
• The transformation of neuronal dynamics through this L5→GrC pathway remains largely unexplored.

Purpose of the Study:

• To investigate how neuronal dynamics are transformed through the L5→GrC pathway during motor learning.
• To compare the neural activity patterns of L5 cells and GrCs during a forelimb movement task.

Main Methods:

• Dual-site two-photon calcium imaging was employed to directly compare premotor L5 and GrC activity in mice during a forelimb movement task.
• Chronic imaging was utilized to observe the emergence of neural dynamics over the course of learning.

Main Results:

• In expert mice, L5 and GrC neural dynamics exhibited striking similarity, sharing task-encoding patterns and response diversity.
• High correlations were observed between L5 and GrC activity, comparable to local correlations within L5 cells.
• Over learning, initially dissimilar L5 and GrC dynamics converged onto a shared, low-dimensional set of task-encoding patterns as behavioral performance improved.

Conclusions:

• A key function of cortico-cerebellar communication is the propagation of shared neural dynamics that emerge during motor learning.
• The L5→GrC pathway facilitates the convergence of cortical and cerebellar activity, supporting refined motor control.