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Organization of cell assemblies in the hippocampus

Nature volume 424, pages 552–556 (2003)Cite this article

Abstract

Neurons can produce action potentials with high temporal precision1. A fundamental issue is whether, and how, this capability is used in information processing. According to the ‘cell assembly’ hypothesis, transient synchrony of anatomically distributed groups of neurons underlies processing of both external sensory input and internal cognitive mechanisms2,3,4. Accordingly, neuron populations should be arranged into groups whose synchrony exceeds that predicted by common modulation by sensory input. Here we find that the spike times of hippocampal pyramidal cells can be predicted more accurately by using the spike times of simultaneously recorded neurons in addition to the animals location in space. This improvement remained when the spatial prediction was refined with a spatially dependent theta phase modulation5,6,7,8. The time window in which spike times are best predicted from simultaneous peer activity is 10–30 ms, suggesting that cell assemblies are synchronized at this timescale. Because this temporal window matches the membrane time constant of pyramidal neurons9, the period of the hippocampal gamma oscillation10 and the time window for synaptic plasticity11, we propose that cooperative activity at this timescale is optimal for information transmission and storage in cortical circuits.

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Figure 1: Cell assembly activity in a population.
Figure 2: Spike train prediction method.
Figure 3: Spike timing is predictable from peer activity.
Figure 4: Assembly structure is not fully accounted for by spatially dependent phase modulation.

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Acknowledgements

We thank J. E. Lisman, D. L. Buhl, S. M. Montgomery, P. E. Bartho and I. Creese for comments on the manuscript. This work was supported by grants from the National Institutes of Health

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Author notes

  1. Jozsef Csicsvari

    Present address: MRC Anatomical Neuropharmacology Unit, Mansfield Road, Oxford, OX1 3TH, UK

Authors and Affiliations

  1. Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, New Jersey, 07102, USA

    Kenneth D. Harris, Jozsef Csicsvari, Hajime Hirase, George Dragoi & György Buzsáki

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Correspondence to György Buzsáki.

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Harris, K., Csicsvari, J., Hirase, H. et al. Organization of cell assemblies in the hippocampus. Nature 424, 552–556 (2003). https://doi.org/10.1038/nature01834

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