Abstract

Local field potential (LFP) oscillations in the granule cell layer of the cerebellar cortex could be a signal representing an organizing influence on its networks. However, little is known about the relative location of these LFP oscillations across the cerebellar cortex topography. LFPs and unit activity were recorded in the cerebellar cortex of 4 immobile adult male rats. Three to eight multiple moveable microelectrodes were simultaneously implanted at three targets (positions) perpendicular to the transverse plane. Recordings were made at regular 0.25 to 0.5 mm intervals, or upon a change in layers, or when capturing a single unit. LFPs were analyzed using Fast Fourier Transforms to calculate the proportion of the signal within 5-10 Hz for consecutive time windows of 500 ms. Recordings were made at multiple depths: for comparisons, track depth was divided in three regions (1/3 of the track depth, with region 1 being superficial and region 3 deep). All rats showed a tendency for increasing oscillatory activity with increasing depth and mean oscillatory activity increased from region 1 to region 3. Oscillatory activity was greater in electrodes located more lateral and caudal. All rats exhibited an interaction between position and region: increased oscillatory activity was found in lower depths of tracks more lateral and caudal, corresponding to position 1, region 3. 5-10 Hz oscillatory activity is isolated to specific subdivisions of the granule cell layer, corresponding to the Crus II and paramedian lobules and could be related to the specific combinations of afferents arriving in these lobules.