Behavior-Related Pauses in Simple-Spike Activity of Mouse Purkinje Cells Are Linked to Spike Rate Modulation

• Authors: Ying Cao, University of Tennessee; Selva K. Maran, Emory University; Mukesh Dhamala, Georgia State University; Dieter Jaeger, Emory University; Detlef H. Heck, University of Tennessee
• Journal Title: Journal of Neuroscience
• Volume: Volume 32, Number 25
• Publisher: Society for Neuroscience | 2012-06-20, Pages 8678-8685
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1523/JNEUROSCI.4969-11.2012
• Subjects: Biology, Neuroscience; Biology, Cell; Physics, General

Abstract

Purkinje cells (PCs) in the mammalian cerebellum express high frequency spontaneous activity with average spike rates between 30 and 200 Hz. Cerebellar nuclear (CN) neurons receive converging input from many PCs resulting in a continuous barrage of inhibitory inputs. It has been hypothesized that pauses in PC activity trigger increases in CN spiking activity. A prediction derived from this hypothesis is that pauses in PC simple spike activity represent relevant behavioral or sensory events. Here we asked whether pauses in the simple spike activity of PCs related to either fluid licking or respiration, play a special role in representing information about behavior. Both behaviors are widely represented in cerebellar PC simple spike activity. We recorded PC activity in the vermis and lobus simplex of head fixed mice while monitoring licking and respiratory behavior. Using cross correlation and Granger causality analysis we examined whether short ISIs had a different temporal relation to behavior than long ISIs or pauses. Behavior related simple spike pauses occurred during low-rate simple spike activity in both licking and breathing related PCs. Granger causality analysis revealed causal relationships between simple spike pauses and behavior. However, the same results were obtained from an analysis of surrogate spike trains with gamma ISI distributions constructed to match rate modulations of behavior related Purkinje cells. Our results therefore suggest that the occurrence of pauses in simple spike activity does not represent additional information about behavioral or sensory events that goes beyond the simple spike rate modulations.