A Study of Audiovisual Integrative Evoked Potentials Using Time-Frequency Independent Component Analysis
Poster Presentation

Xilong Zhi
Kyushu Institute of Technology

Yasuhiko Saito
Ashikaga Institute of Technology

Huaying Jin
Ashikaga Institute of Technology

     Abstract ID Number: 11
     Full text: Not available
     Last modified: May 30, 2007
     Presentation date: 07/06/2007 10:00 AM in Quad Maclauren Hall
     (View Schedule)

Abstract
Objectives: Event-related synchronization and desynchronization (ERS/ERD) effects reflect induced changes in cortical oscillatory power that do not result in a strong average-evoked response. In current study, we present independent component analysis (ICA) approach to decompose the time-frequency representation (TFR) of audiovisually evoked potentials to investigate the functional correlation of EEG ERS/ERD components with the interaction of sensory modalities following audio-visual stimulation.
Methods: In an experimental study (8 subjects), we subtracted the TFR of auditory evoked potentials and visual evoked potentials from that of bimodal evoked potentials. The time-frequency ICA was performed for difference TFR. Three time-frequency ICs were extracted then were used to perform spatial mapping.
Results: ERS effects was observed in left temporal cortex (19~21 Hz, 308ms post-stimulus), in the same location, ERD effects were also observed (28~29 Hz, 232~234ms post-stimulus). We also observed ERD effects in right temporal- parietal cortex (5~7 Hz, 184ms post-stimulus) and occipital cortex (14~15 Hz, 232ms post-stimulus).
Conclusions: Audiovisual integrative activity that overlapped in time, frequency, and topography were effectively separated and extracted. The audiovisual interactive ERS/ERD effects can be observed in both associative cortex and primary cortex where also observed interactive event-related potential (ERP) effects in previous study.