Motor learning induces astrocytic hypertrophy in the cerebellar cortex

Area of Science:

• Neuroscience
• Cell Biology
• Motor Learning

Background:

• Motor skill learning induces structural changes in the cerebellum, including increased synapse number and glial cell volume.
• Synapse number increases persist post-training, but the persistence of glial cell changes is less understood.

Purpose of the Study:

• To investigate the impact of training interruption on learning-induced astrocytic volume increases in the cerebellar cortex.
• To compare the persistence of astrocytic hypertrophy with that of synaptogenesis following motor learning.

Main Methods:

• Adult female rats underwent acrobatic motor learning (AC) or a motor control (MC) task.
• Animals were trained for 10 days, with some experiencing a 28-day delay before further training or continuous training for 38 days.
• Unbiased stereological techniques quantified astrocytic volume per Purkinje cell in the cerebellar paramedian lobule.

Main Results:

• AC animals showed significantly greater astrocytic volume per Purkinje cell than MC animals.
• This difference in astrocytic volume was significantly reduced and not statistically detectable in the delay condition (post-training interruption).
• Astrocytic hypertrophy was dependent on continued training, unlike persistent synaptogenesis.

Conclusions:

• Motor skill learning induces astrocytic hypertrophy in the cerebellum.
• Unlike synaptogenesis, astrocytic growth associated with motor learning is not persistent and diminishes without continued training.
• These findings highlight distinct structural plasticity mechanisms underlying motor learning and memory consolidation.