Mathematical analyses and simulations predict conditions for the emergence of slow population rhythms

Abstract

Event Abstract Back to Event Mathematical analyses and simulations predict conditions for the emergence of slow population rhythms Ernest Ho1*, L. Zhang2 and Frances K. Skinner3 1 University of Toronto, Department of Physiology, Canada 2 Toronto Western Research Institute, Canada 3 Toronto Western Res. Inst., Univ. Health Network, Canada Inhibitory, interneuronal networks are known to underlie high frequency gamma population activities in several brain regions including hippocampus. Because network mechanisms involve fast inhibitory GABAA receptor decay time constants (5-10ms), individual interneurons are able to synchronize each other and sustain high frequency population activities. Interneuronal networks are also known to underlie low frequency population rhythms - 0.5-4 Hz spontaneous in vitro rhythms in hippocampus (Wu et al., J Neurophysiol 93:2302-2317,2005) that likely constitute part of the in vivo activities that occur during slow wave sleep. However, it is unclear how the same interneuronal network system can give rise to slow populations rhythms in the absence of an explicit slow timescale. We show, via simulations of 90-cell interneuronal network models, that slow rhythms can emerge without any explicit slow timescale. We find that two crucial prerequisites are required for slow rhythms to occur: 1) suitable synaptic background activities (SBAs), and 2) a fast spiking onset of the model interneurons. We have determined the model SBA parameters needed to give rise to the slow population rhythms using a reduced low-dimensional mean field theory model. Also, from our network models we have found that the optimal rate of spike onset of constituent interneurons at the threshold should be approximately ten times that of the Wang-Buzsaki interneuron model. Given the results of our simulations and analyses, we hypothesize that biological interneuronal networks must share these prerequisites for slow rhythms to emerge. We examine our hypothesis using our previously quantified SBAs from in vitro hippocampal preparations exhibiting slow oscillations (Ho et al., Hippocampus 19(2):152-165, 2009). We find a correspondence between model and experiment which strongly suggests that the balance of excitatory and inhibitory synaptic conductances in the SBAs is critical for the emergence of slow population rhythms. Conference: B.R.A.I.N. platform in Physiology poster day 2009, Toronto, ON, Canada, 16 Dec - 16 Dec, 2009. Presentation Type: Poster Presentation Topic: Poster presentations Citation: Ho E, Zhang L and Skinner FK (2009). Mathematical analyses and simulations predict conditions for the emergence of slow population rhythms. Front. Neurosci. Conference Abstract: B.R.A.I.N. platform in Physiology poster day 2009. doi: 10.3389/conf.neuro.03.2009.17.021 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 17 Dec 2009; Published Online: 17 Dec 2009. * Correspondence: Ernest Ho, University of Toronto, Department of Physiology, Toronto, Canada, ecy.ho@utoronto.ca Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ernest Ho L. Zhang Frances K Skinner Google Ernest Ho L. Zhang Frances K Skinner Google Scholar Ernest Ho L. Zhang Frances K Skinner PubMed Ernest Ho L. Zhang Frances K Skinner Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.