Abstract

Local field potential (LFP) oscillations within the granule cell layer (GCL) of the cerebellar cortex have been recorded in the alert, awake rat at frequencies between 5-15 Hz. In rodents and primates, these oscillations occur while the animal is immobile, and terminate with the initiation of movement. The low-frequency oscillations are related to Golgi-granule cell activity; Golgi cells afferent connections show strong divergence and are heavily implicated with the temporal organization of the cerebellar cortex. Gap junctions have been identified within the GCL between Golgi cells, indicating a possible mechanism by which the Golgi cells electrical potential could spread quickly across the GCL, synchronizing the oscillations. Here, the presence of these oscillations under anesthesia was recorded in order to study both the regional specificity and if these oscillations can be pharmacologically modulated. Regional specificity was of oscillations was shown with the recordings in cerebellar cortex across multiple channels. These oscillations are related to Golgi-granule cell activity: a modulatory factor might be gap junction connections between Golgi cells, which are believed to be involved in the synchronization of neuron populations resulting in synchronous rhythms. To investigate the modulatory effect of gap junctions, the oscillatory power of signal in the presence of gap junction blockers carbenoxlone and mefloquine was examined. Drugs were locally introduced into the cerebellar cortex, resulting in a consistent decrease in the power in oscillations between 5-15 Hz. These findings add to the mechanistic description of the genesis of cerebellar GCL oscillations.