Original Research ARTICLE

Front. Integr. Neurosci., 12 October 2012 | http://dx.doi.org/10.3389/fnint.2012.00090

Monosynaptic functional connectivity in cerebral cortex during wakefulness and under graded levels of anesthesia

Jeannette A. Vizuete1, Siveshigan Pillay2, Kamran Diba3, Kristina M. Ropella1 and Anthony G. Hudetz4*
  • 1Department of Biomedical Engineering, Marquette University, Milwaukee, WI, USA
  • 2Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA
  • 3Department of Psychology, University of Wisconsin at Milwaukee, Milwaukee, WI, USA
  • 4Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA

The balance between excitation and inhibition is considered to be of significant importance for neural computation and cognitive function. Excitatory and inhibitory functional connectivity in intact cortical neuronal networks in wakefulness and graded levels of anesthesia has not been systematically investigated. We compared monosynaptic excitatory and inhibitory spike transmission probabilities using pairwise cross-correlogram (CCG) analysis. Spikes were measured at 64 sites in the visual cortex of rats with chronically implanted microelectrode arrays during wakefulness and three levels of anesthesia produced by desflurane. Anesthesia decreased the number of active units, the number of functional connections, and the strength of excitatory connections. Connection probability (number of connections per number of active unit pairs) was unaffected until the deepest anesthesia level, at which a significant increase in the excitatory to inhibitory ratio of connection probabilities was observed. The results suggest that the excitatory–inhibitory balance is altered at an anesthetic depth associated with unconsciousness.

Keywords: consciousness, cross-correlogram analysis, cortical monosynaptic connectivity, excitatory–inhibitory balance, connection strength

Citation: Vizuete JA, Pillay S, Diba K, Ropella KM and Hudetz AG (2012) Monosynaptic functional connectivity in cerebral cortex during wakefulness and under graded levels of anesthesia. Front. Integr. Neurosci. 6:90. doi: 10.3389/fnint.2012.00090

Received: 10 July 2012; Paper pending published: 04 August 2012;
Accepted: 20 September 2012; Published online: 12 October 2012.

Edited by:

John J. Foxe, Albert Einstein College of Medicine, USA

Reviewed by:

Pierre Megevand, Albert Einstein College of Medicine of Yeshiva University, USA
Eugene F. Civillico, Food and Drug Administration, USA

Copyright © 2012 Vizuete, Pillay, Diba, Ropella and Hudetz. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.

*Correspondence: Anthony G. Hudetz, Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA. e-mail: ahudetz@mcw.edu