Skip to content

Advertisement

  • Poster presentation
  • Open Access

Two different mechanisms alternate during cortical synchronized states

BMC Neuroscience201516 (Suppl 1) :P264

https://doi.org/10.1186/1471-2202-16-S1-P264

  • Published:

Keywords

  • Independent Component Analysis
  • Brain State
  • Slow Oscillation
  • Synchronize State
  • Theta Oscillation

Brain states can be classified as synchronized (large amplitude low frequency oscillations) or desynchronized (small amplitude high frequency activity). [1] Synchronized states are marked by UP states/phases characterized by global spiking and DOWN states/phases are characterized by global silence in the cortex. In awake animals, desynchronized states are associated with processing sensory input and behavior while synchronized states are associated with quiet idling conditions. During sleep, REM is considered desynchronized and slow-wave sleep is considered synchronized. While desynchronized brain states are often triggered by various kinds of neuronal input to cortical areas, the exact mechanism at work during synchronized brain states is still unclear. In particular, there are two hypothesized mechanisms for the slow oscillation during slow-wave sleep: UP phases can be produced either by traveling neocortical waves or a thalamo-cortical loop [24].

In our study, applying independent component analysis (ICA) to recordings from rat neocortex reveals two different mechanisms during synchronized activity. The mechanisms are distinguished by two key neural sources identified by ICA: a strong broad source centered in layer 5 (BL5) and an apparent sub-cortical source producing clock-like oscillations which resemble hippocampal theta oscillations (SUB). The BL5-state often resembles cortically generated oscillations: UP phases are initiated in deeper layers akin to traveling neocortical waves and the oscillation is relatively slow. The SUB-state can resemble thalamo-cortically generated oscillations: UP phases are initiated in layer 4 as well as deeper layers and the oscillation is faster. These findings suggest that both hypothesized mechanisms for the slow oscillation are at work in the cortex - in alternation.

Declarations

Acknowledgements

We would like to thank Austin Brockmeier for helpful discussions with ICA. Waking data was originally published in Sakata & Harris (2009) and Sakata & Harris (2012). This work was supported by the RIKEN Brain Science Institute, Medical Research council (MR/J004448/1), Tenovus Scotland (S11/1), Deafness Research UK (552:STR:SS), Medical Research Council (MR/J004448/1), and Biotechnology and Biological Sciences Research Council (BB/K016830/1)

Authors’ Affiliations

(1)
Brain Science Institute, RIKEN, Wakoshi 351-0198, Japan
(2)
Centre for Neuroscience, University of Strathclyde, Glasgow, G4 ORE, UK

References

  1. Harris K, Thiele A: Cortical state and attention. Nat Rev Neur. 2011, 12 (9): 509-523.View ArticleGoogle Scholar
  2. Massimini M, Huber R, Ferrarelli F, Hill S, Tononi G: The sleep slow oscillation as a traveling wave. J Neurosci. 2004, 24 (31): 6862-6870.PubMedView ArticleGoogle Scholar
  3. Crunelli V, Hughes SW: The slow (<1Hz) rhythm of non-REM sleep: a dialogue between three cardinal oscillators. Nat Neurosci. 2010, 13 (1): 9-17.PubMedPubMed CentralView ArticleGoogle Scholar
  4. David F, Schmiedt JT, Taylor HL, Orban G, Di Giovanni G, Uebele VN, Renger JJ, Lambert RC, Leresche N, Crunelli V: Essential thalamic contribution to slow waves of natural sleep. J Neurosci. 2013, 33 (50): 19599-19610.PubMedPubMed CentralView ArticleGoogle Scholar

Copyright

© Munro et al. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Advertisement