J.S.H. and T.K. contributed equally to this work.
Rate maintenance and resonance in the entorhinal cortex
Version of Record online: 29 OCT 2010
© 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd
European Journal of Neuroscience
Volume 32, Issue 11, pages 1930–1939, December 2010
How to Cite
Haas, J. S., Kreuz, T., Torcini, A., Politi, A. and Abarbanel, H. D. I. (2010), Rate maintenance and resonance in the entorhinal cortex. European Journal of Neuroscience, 32: 1930–1939. doi: 10.1111/j.1460-9568.2010.07455.x
- Issue online: 28 NOV 2010
- Version of Record online: 29 OCT 2010
- Received 20 April 2010, accepted 26 August 2010
- entorhinal cortex;
Throughout the brain, neurons encode information in fundamental units of spikes. Each spike represents the combined thresholding of synaptic inputs and intrinsic neuronal dynamics. Here, we address a basic question of spike train formation: how do perithreshold synaptic inputs perturb the output of a spiking neuron? We recorded from single entorhinal principal cells in vitro and drove them to spike steadily at ∼5 Hz (theta range) with direct current injection, then used a dynamic-clamp to superimpose strong excitatory conductance inputs at varying rates. Neurons spiked most reliably when the input rate matched the intrinsic neuronal firing rate. We also found a striking tendency of neurons to preserve their rates and coefficients of variation, independently of input rates. As mechanisms for this rate maintenance, we show that the efficacy of the conductance inputs varied with the relationship of input rate to neuronal firing rate, and with the arrival time of the input within the natural period. Using a novel method of spike classification, we developed a minimal Markov model that reproduced the measured statistics of the output spike trains and thus allowed us to identify and compare contributions to the rate maintenance and resonance. We suggest that the strength of rate maintenance may be used as a new categorization scheme for neuronal response and note that individual intrinsic spiking mechanisms may play a significant role in forming the rhythmic spike trains of activated neurons; in the entorhinal cortex, individual pacemakers may dominate production of the regional theta rhythm.