Present address: Department of Clinical Neurobiology, University Hospital for Neurology, Im Neuenheimer Feld 364, D–69120 Heidelberg, Germany.
Frequency of network synchronization in the hippocampus marks learning
Article first published online: 28 JUN 2008
© The Authors (2008). Journal Compilation © Federation of European Neuroscience Societies and Blackwell Publishing Ltd
European Journal of Neuroscience
Volume 27, Issue 11, pages 3035–3042, June 2008
How to Cite
Ponomarenko, A. A., Li, J.-S., Korotkova, T. M., Huston, J. P. and Haas, H. L. (2008), Frequency of network synchronization in the hippocampus marks learning. European Journal of Neuroscience, 27: 3035–3042. doi: 10.1111/j.1460-9568.2008.06232.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Received 9 January 2008, revised 20 March 2008, accepted 27 March 2008
- interval schedule;
- ripple oscillations
The synchronization of neuronal networks may be instrumental in plasticity and learning. Hippocampal high-frequency oscillations (140–200 Hz, ‘ripples’) characteristic of consummatory behaviours are thought to promote memory formation. We recorded ripple oscillations from the CA1 area in temporal learning tasks. Rats learned to adjust their operant response to the timing of food reward delivery [fixed interval schedule (FI)]. The intrinsic frequency of ripples was elevated following the switch in reinforcement timing. Learning, as assessed from the response pattern, correlated with fluctuations of intraripple frequency and amplitude. Changes in motor activity did not account for the variability of ripple oscillations. At the same time, features of ripples were unaltered when the fixed interval of reward delivery was changed but did not depend on the lever press response. Thus, in addition to the known replay of neuronal firing patterns during ripple oscillations, the rhythm itself appears to be modulated in an experience-specific way and represents a direct correlate of learning.