N A Laskaris1, A A Ioannides. 1. Laboratory for Human Brain Dynamics, Brain Science Institute, RIKEN, Wako-shi 351-01, Japan.
Abstract
OBJECTIVE: An exploratory data analysis framework, based on minimal spanning tree, is proposed as a means to support the analysis of single trial (ST) electrophysiological signals. The core of this framework is the compact description of the input ST sample in a form of content-dependent ordered lists. Based on the established hierarchies, efficient ways to increase the SNR, extract prototypical responses, visualize possible self-organization trends in the sample and track the course of evoked response along the trial-to-trial dimension, are proposed. METHOD: Magnetoencephalographic auditory evoked responses were used for demonstrating and validating the introduced framework. RESULTS AND CONCLUSION: The results demonstrate the benefits, from this intelligent manipulation of STs, in understanding and enhancing the actual evoked signal. Specifically we find support for stimulus-induced phase-resetting hypothesis in the 3-20 Hz band, the existence of trials void of the prototypical evoked response, and an order across the single trial set hinting at an underlying process with long time scale.
OBJECTIVE: An exploratory data analysis framework, based on minimal spanning tree, is proposed as a means to support the analysis of single trial (ST) electrophysiological signals. The core of this framework is the compact description of the input ST sample in a form of content-dependent ordered lists. Based on the established hierarchies, efficient ways to increase the SNR, extract prototypical responses, visualize possible self-organization trends in the sample and track the course of evoked response along the trial-to-trial dimension, are proposed. METHOD:Magnetoencephalographic auditory evoked responses were used for demonstrating and validating the introduced framework. RESULTS AND CONCLUSION: The results demonstrate the benefits, from this intelligent manipulation of STs, in understanding and enhancing the actual evoked signal. Specifically we find support for stimulus-induced phase-resetting hypothesis in the 3-20 Hz band, the existence of trials void of the prototypical evoked response, and an order across the single trial set hinting at an underlying process with long time scale.
Authors: Andreas A Ioannides; George K Kostopoulos; Nikolaos A Laskaris; Lichan Liu; Tadahiko Shibata; Marc Schellens; Vahe Poghosyan; Ara Khurshudyan Journal: Hum Brain Mapp Date: 2002-04 Impact factor: 5.038
Authors: Andrew A Fingelkurts; Alexander A Fingelkurts; Reetta Kivisaari; Eero Pekkonen; Risto J Ilmoniemi; Seppo Kähkönen Journal: Hum Brain Mapp Date: 2004-05 Impact factor: 5.038