Hippocampal theta-driving cells revealed by Granger causality
Article first published online: 14 MAR 2012
Copyright © 2012 Wiley Periodicals, Inc.
Volume 22, Issue 8, pages 1781–1793, August 2012
How to Cite
Zhang, L., Chen, G., Niu, R., Wei, W., Ma, X., Xu, J., Wang, J., Wang, Z. and Lin, L. (2012), Hippocampal theta-driving cells revealed by Granger causality. Hippocampus, 22: 1781–1793. doi: 10.1002/hipo.22012
- Issue published online: 11 JUL 2012
- Article first published online: 14 MAR 2012
- Manuscript Accepted: 30 JAN 2012
- National Natural Science Foundation of China. Grant Number: 30990262
- Innovation Program of Shanghai Municipal Education Commission. Grant Number: 09ZZ44
- theta oscillations;
- theta-locked interneurons;
- theta-driving cells;
- Granger causality
The two-dipole model of theta generation in hippocampal CA1 suggests that the inhibitory perisomatic theta dipole is generated by local GABAergic interneurons. Various CA1 interneurons fire preferentially at different theta phases, raising the question of how these theta-locked interneurons contribute to the generation of theta oscillations. We here recorded interneurons in the hippocampal CA1 area of freely behaving mice, and identified a unique subset of theta-locked interneurons by using the Granger causality approach. These cells fired in an extremely reliable theta-burst pattern at high firing rates (∼90 Hz) during exploration and always locked to ascending phases of the theta waves. Among theta-locked interneurons we recorded, only these cells generated strong Granger causal influences on local field potential (LFP) signals within the theta band (4–12 Hz), and the influences were persistent across behavioral states. Our results suggest that this unique type of theta-locked interneurons serve as the local inhibitory theta dipole control cells in shaping hippocampal theta oscillations. © 2012 Wiley Periodicals, Inc.