Neocortical networks entrain neuronal circuits in cerebellar cortex

Area of Science:

• Neuroscience
• Systems Neuroscience
• Computational Neuroscience

Background:

• Neocortical activity is characterized by synchronized neuronal oscillations generating local field potentials (LFPs).
• The existence and origin of synchronized oscillations within the cerebellum, and their relationship to neocortical activity, remain largely unexplored.

Purpose of the Study:

• To investigate whether the cerebellar cortex generates synchronized oscillations.
• To determine if cerebellar oscillations are influenced by neocortical activity.
• To elucidate the cellular mechanisms underlying cerebellar slow oscillations.

Main Methods:

• Recording local field potentials (LFPs) in the cerebellum and neocortex of anesthetized and awake animals.
• Perturbing neocortical oscillations and observing effects on cerebellar activity.
• Blocking cerebellar activity to assess its influence on the neocortex.
• Analyzing neuronal firing patterns (single and complex spikes) of cerebellar neurons during oscillations.

Main Results:

• The cerebellar cortex exhibits a slow oscillation correlated with neocortical oscillations, even without external stimuli.
• Disruption of neocortical oscillations abolished cerebellar oscillations, while cerebellar disruption had no effect on the neocortex.
• Granule, Golgi, and Purkinje neurons are activated during the "up" state of the cerebellar slow oscillation, with specific firing patterns observed.
• Correlations between neocortical and cerebellar LFPs persist in awake animals, indicating sustained modulation.

Conclusions:

• The cerebellum generates rhythmic network activity (slow oscillations) that is driven by synchronized neocortical oscillations.
• Neocortical projection neurons exert a significant driving and modulatory influence on cerebellar network activity.
• This neocortical influence on the cerebellum is maintained across different states, including natural behaviors.