The investigation on the source localizations and the isofrequency bands of auditory evoked N100m on-response and off-response magnetic signals by a 128 cannels low-Tc SQUID magnetoencephalography system

Abstract

Event Abstract Back to Event The investigation on the source localizations and the isofrequency bands of auditory evoked N100m on-response and off-response magnetic signals by a 128 cannels low-Tc SQUID magnetoencephalography system Kuen-Lin Chen1*, Hong-Chang Yang1, Sung-Ying Tsai2, Herng-Er Horng2, YongHo Lee3, Hyukchan Kwon3, Ming-Jang Chiu4, Chih-Chuan Chen4 and Ruey-Meei Wu4 1 National Taiwan University, Department of Physics, Taiwan 2 National Taiwan Normal University, Institute of Electro-optical Science and Technology, Taiwan 3 Korea Research Institute of Standards and Science, South Korea 4 National Taiwan University Hospital, Department of Neurology, Taiwan A 128 channels helmet-shaped first order low-Tc axial gradiometer SQUID magnetoencephalography (MEG) system is used to study the auditory evoked responses. The axial gradiometers show an averaged noise level of 3.5 fT/Hz1/2 at 100 Hz inside magnetically shielded room. The measurements were performed with the monaural 500 Hz, 1 KHz and 2 KHz pure tone stimuli of 75 dB sound pressure level persisting for 300 ms to the left or right ears of subjects. The auditory evoked fields (AEFs) around 100 ms after the stimuli onset are defined as N100m on-responses, and the AEFs around 100 ms after the cessation of stimuli are defined as N100m off-responses. The superiority of MEG on temporal resolution, which is better than MRI, allows us to study the evolution of equivalent current dipole (ECD) for N100m on-responses and N100m off-responses. The independent component analysis (ICA) method was used to determine the latencies of the AEFs’ peaks. The software CURRY was also used to calculate the source locations of equivalent current dipoles of N100m on-response and N100m off-response. The spatial distribution and time evolution of the ECDs were investigated. It was found that the ECD locations of N100m off-responses were more interior than that of on-response, which indicated different neuron activities in the auditory cortex. We also found that the movement traces of ECDs around the peak latency for the N100m on- and off-response individually formed the isofrequency bands. The distributions of the isofrequency bands were highly relative to the frequency of sound. The formation of isofrequency band for the N100m off-response signal showed that the cessation of a sound was also an event which could induce the neuron activity in the human auditory cortex. The experimental data suggested that brain used different neurons in the auditory cortex to process the information for the onset and cessation of sound. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Sensory Processing and Functional Connectivity Citation: Chen K, Yang H, Tsai S, Horng H, Lee Y, Kwon H, Chiu M, Chen C and Wu R (2010). The investigation on the source localizations and the isofrequency bands of auditory evoked N100m on-response and off-response magnetic signals by a 128 cannels low-Tc SQUID magnetoencephalography system. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00197 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: 29 Mar 2010; Published Online: 29 Mar 2010. * Correspondence: Kuen-Lin Chen, National Taiwan University, Department of Physics, Taipei, Taiwan, d92222016@ntu.edu.tw 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 Kuen-Lin Chen Hong-Chang Yang Sung-Ying Tsai Herng-Er Horng YongHo Lee Hyukchan Kwon Ming-Jang Chiu Chih-Chuan Chen Ruey-Meei Wu Google Kuen-Lin Chen Hong-Chang Yang Sung-Ying Tsai Herng-Er Horng YongHo Lee Hyukchan Kwon Ming-Jang Chiu Chih-Chuan Chen Ruey-Meei Wu Google Scholar Kuen-Lin Chen Hong-Chang Yang Sung-Ying Tsai Herng-Er Horng YongHo Lee Hyukchan Kwon Ming-Jang Chiu Chih-Chuan Chen Ruey-Meei Wu PubMed Kuen-Lin Chen Hong-Chang Yang Sung-Ying Tsai Herng-Er Horng YongHo Lee Hyukchan Kwon Ming-Jang Chiu Chih-Chuan Chen Ruey-Meei Wu 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.