Modulation of Spontaneous Cortical Network Dynamics by Weak Global Perturbations

Abstract

Event Abstract Back to Event Modulation of Spontaneous Cortical Network Dynamics by Weak Global Perturbations Flavio Frohlich1* 1 UNC Chapel Hill, Dept. of Psychiatry, United States Transcranial current stimulation (TCS) represents a non-invasive brain stimulation paradigm that manipulates cortical networks by application of weak electric fields. Such stimulation causes very small changes in the membrane voltage of individual neurons (< 1 mV) yet has pronounced effects on the overall rhythmic activity structure in cortex. For example, weak sine-wave electric fields enhanced slow oscillations during deep sleep in human EEGs [1] and modulated the rhythmic structure of network activity at the spiking level in vitro [2,3]. However, the underlying mechanisms that mediate this network effect remain poorly understood. We used large-scale computer simulations of cortical networks to probe how weak yet global perturbations shape macroscopic dynamics in network models with different topologies. Our computational model was comprised of 1 million pyramidal neurons and 2250’000 fast spiking inhibitory interneurons that were connected with excitatory and inhibitory synapses. The model neurons were based on the Izhikevich model, which combines biological plausibility of spike initiation dynamics with high computational efficiency. We found that the stimulation waveform crucially determines the effect of TCS on network dynamics. Constant stimulation (tDCS, transcranial direct current stimulation) had a very limited effect on overall oscillation structure in comparison to sine-wave perturbations. For such periodic stimulation, we found that the presence of network level resonance depended on the underlying mechanisms that generated the spontaneous oscillations. We further found that both (1) network topology and (2) intrinsic excitability profiles crucially determined the effect magnitude of global weak perturbations applied to cortical networks. Together, our results indicate that weak global perturbations can represent effective network modulators and that they act through amplification at the level of individual neurons at spiking threshold and at the level of the entire network through propagation by synaptic connectivity. Our results provide mechanistic insights into how TCS can modulate spontaneous cortical network dynamics and therefore provide the starting point for pre-clinical trials of optimized, more dynamic stimulation waveforms. [1] Marshall, L., et al.,Nature, 2006. 444(7119) [2] Fröhlich, F. and D. McCormick, Neuron, 2010. 67(1) [3] Reato, D., et al., J Neurosci, 2010. 30(45) Keywords: computational neuroscience, cortical networks, modulation, brain simulation, large scale simulation Conference: 5th INCF Congress of Neuroinformatics, Munich, Germany, 10 Sep - 12 Sep, 2012. Presentation Type: Poster Topic: Neuroinformatics Citation: Frohlich F (2014). Modulation of Spontaneous Cortical Network Dynamics by Weak Global Perturbations. Front. Neuroinform. Conference Abstract: 5th INCF Congress of Neuroinformatics. doi: 10.3389/conf.fninf.2014.08.00093 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: 21 Mar 2013; Published Online: 27 Feb 2014. * Correspondence: Dr. Flavio Frohlich, UNC Chapel Hill, Dept. of Psychiatry, Chapel Hill, United States, flavio_frohlich@med.unc.edu 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 Flavio Frohlich Google Flavio Frohlich Google Scholar Flavio Frohlich PubMed Flavio Frohlich 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.