Stochastic and deterministic dynamics of intrinsically irregular firing in cortical inhibitory interneurons
- University of Cambridge, United Kingdom
- University of Southampton, United Kingdom
- Institute of Experimental Medicine, Hungary
Abstract
Most cortical neurons fire regularly when excited by a constant stimulus. In contrast, irregular-spiking (IS) interneurons are remarkable for the intrinsic variability of their spike timing, which can synchronize amongst IS cells via specific gap junctions. Here, we have studied the biophysical mechanisms of this irregular spiking in mice, and how IS cells fire in the context of synchronous network oscillations. Using patch-clamp recordings, artificial dynamic conductance injection, pharmacological analysis and computational modelling, we show that spike time irregularity is generated by a nonlinear dynamical interaction of voltage-dependent sodium and fast-inactivating potassium channels just below spike threshold, amplifying channel noise. This active irregularity may help IS cells synchronize with each other at gamma range frequencies, while resisting synchronization to lower input frequencies.
Article and author information
Author details
Mariana Vargas-Caballero
Funding
Biotechnology and Biological Sciences Research Council
- Ole Paulsen
- Hugh PC Robinson
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
- Philipe RF Mendonça
Cambridge Overseas Trust
- Philipe RF Mendonça
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: Experimental procedures and animal use were in accordance with the animal care guidelines of the UK Animals (Scientific Procedures) Act 1986 under Home Office project license PPL80/2440 and personal licenses held by the authors. Caution wastaken to minimize stress and the number of animals used in experiments.
Copyright
© 2016, Mendonça et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Stochastic and deterministic dynamics of intrinsically irregular firing in cortical inhibitory interneurons
eLife 5:e16475.
https://doi.org/10.7554/eLife.16475
