Evoked potentials and evoked ripples in the human hippocampal formation

Abstract

Event Abstract Back to Event Evoked potentials and evoked ripples in the human hippocampal formation Daniel Fabo1, 2*, Z. Magloczky3, E. Toth4, L. Eross2, A. Solyom2, S. Czirjak2, G. Rasonyi2, P. Halasz4, T. F. Freund3, G. Karmos1, 4 and I. Ulbert1, 2, 4 1 Institute for Psychology, Hungarian Academy of Sciences, Hungary 2 National Institute of Neurosurgery, Hungary 3 Institute of Experimental Medicine, Hungarian Academy of Sciences, Hungary 4 Peter Pazmany Catholic University, Hungary Intracranial electrical stimulation (IES) is a main candidate for future therapy of drug resistant epilepsies. However, the current knowledge on the effect of IES is poorly understood. Under general anesthesia we inserted laminar multielectrodes into the hippocampal formation (HF) of five temporal lobe epilepsy (TLE) patients to record local field potential (LFP), multiple unit activity (MUA), current source density (CSD) and spectral activation of evoked potentials (EPs) elicited by brief, singe pulse, subdural cortical electrical stimuli (0.1ms; 5- 15mA; 0.5Hz). LFP based ripple detection algorhythm was developed. The EPs started with a 10-50ms spike, and ended with a 100-500ms slow wave. The spike was characterized by CSD sink and MUA increase. In one case, the onset latency was less than 5ms. The fastest responses were elicited from a 2-4cm cortical region. The CSD pattern at a particular recording site varied with stimulus site and strength. High frequency oscillation activity was measured during the initial sink. Ripple activity was elicited with 60-98% probability preferably from more anterior sites. Both ripples and fast ripples could be evoked both in the subiculum and the dentate gyrus. During the slow wave, high frequency activity was depressed. We conclude that the HF’s response amplitude is stimulus strength dependent, while the time course of the EP depends on the location of the stimulation site suggesting differently activated afferent fiber systems. Since IES evokes increased ripple/fast ripple activity, it is of utmost importance to further investigate different stimulation paradigms to expose the most beneficial anti-epileptic stimulation parameters. Conference: 12th Meeting of the Hungarian Neuroscience Society, Budapest, Hungary, 22 Jan - 24 Jan, 2009. Presentation Type: Poster Presentation Topic: Research on the cerebral cortex and related structures Citation: Fabo D, Magloczky Z, Toth E, Eross L, Solyom A, Czirjak S, Rasonyi G, Halasz P, Freund TF, Karmos G and Ulbert I (2009). Evoked potentials and evoked ripples in the human hippocampal formation. Front. Syst. Neurosci. Conference Abstract: 12th Meeting of the Hungarian Neuroscience Society. doi: 10.3389/conf.neuro.01.2009.04.191 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: 06 Mar 2009; Published Online: 06 Mar 2009. * Correspondence: Daniel Fabo, Institute for Psychology, Hungarian Academy of Sciences, Budapest, Hungary, fabo.daniel@gmail.com 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 Daniel Fabo Z. Magloczky E. Toth L. Eross A. Solyom S. Czirjak G. Rasonyi P. Halasz T. F Freund G. Karmos I. Ulbert Google Daniel Fabo Z. Magloczky E. Toth L. Eross A. Solyom S. Czirjak G. Rasonyi P. Halasz T. F Freund G. Karmos I. Ulbert Google Scholar Daniel Fabo Z. Magloczky E. Toth L. Eross A. Solyom S. Czirjak G. Rasonyi P. Halasz T. F Freund G. Karmos I. Ulbert PubMed Daniel Fabo Z. Magloczky E. Toth L. Eross A. Solyom S. Czirjak G. Rasonyi P. Halasz T. F Freund G. Karmos I. Ulbert 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.