The Journal of Neuroscience, 1999:RC6:1-5
RAPID COMMUNICATION
Parallel Fibers Synchronize Spontaneous Activity in Cerebellar
Golgi Cells
Bart P.
Vos,
Reinoud
Maex,
Antonia
Volny-Luraghi, and
Erik
De
Schutter
Laboratory for Theoretical Neurobiology, Born-Bunge Foundation,
University of Antwerp, B2610 Antwerp, Belgium
Cerebellar Golgi cells inhibit their afferent interneurons, the
excitatory granule cells. Such a feedback inhibition causes both
inhibitory and excitatory neurons in the circuit to synchronize. Our
modeling work predicts that the long granule cell axons, the parallel
fibers, entrain many Golgi cells and their afferent granule cells in a
single synchronous rhythm. Spontaneous activity of 42 pairs of putative
Golgi cells was recorded in anesthetized rats to test these
predictions. In 25 of 26 pairs of Golgi cells that were positioned
along the transverse axis, and presumed to receive common parallel
fiber input, spontaneous activity showed a high level of coherence
(mean Z score > 6). Conversely, 12 of 16 Golgi
cell pairs positioned along the parasagittal axis (no common parallel
fiber input) were not synchronized; 4 of 16 of them showed only low
levels of synchronicity (mean Z score < 4). For
transverse pairs the accuracy of the coherence, measured as the width
at half-height of the central peak of the cross-correlogram, was rather
low (29.8 ± 12.5 msec) but increased with Golgi cell firing rate,
as predicted by the model. These results suggest that in addition to
their role as gain controllers, cerebellar Golgi cells may control the
timing of granule cell spiking.
Key words:
cerebellum; coherence; computer models; cross-correlation; Crus II; rat
Copyright © 1999 Society for Neuroscience 0270-6474/99/$05.00/0