Hierarchical decomposition of dichoptic multifocal visual evoked potentials
Date
2006
Authors
Maddess, Ted
James, Andrew
Ruseckaite, Rasa
Bowman, Elizabeth
Journal Title
Journal ISSN
Volume Title
Publisher
Cambridge University Press
Abstract
Visual evoked responses to dichoptically presented multifocal stimuli were recorded for 92 eyes. Two stimulus variants were explored: temporally sparse and rapidly contrast reversing. We used hierarchal decomposition (HD) to represent the multifocal responses in terms of a small number of potentially unique component waveforms that are interrelated in a multivariate linear autoregressive (MLAR) relationship. The HD method exploits temporal correlations over a range of delays in the responses to estimate parallel, feedforward and feedback relationships between the HD components. Three HD components having temporal interrelationships constrained (at P < 0.05) to a moving ∼20 ms window could describe the multifocal responses well (median r2-values up to 90%). HD components were similar for both stimulus types and the component waveforms were temporally correlated, especially the first and third components. The data set was large enough to estimate separate HD components for each multifocal stimulus region. The component waveforms differed somewhat by region but the MLAR relationships were similar. At short delays parallel processing dominated. At longer delays the proportion of response drives that were attributed to feedback and feedforward relationships grew. Overall HD analysis seems to provide an informed summary of multifocal responses and insights into their sources.
Description
Keywords
Keywords: article; controlled study; evoked visual response; feedback system; nonhuman; principal component analysis; priority journal; stimulus response; visual stimulation; waveform; Adult; Contrast Sensitivity; Electroencephalography; Evoked Potentials, Visual; Hierarchical decomposition; mfVEP; Multifocal; Principal components; Sparse; Visual evoked potentials
Citation
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Source
Visual Neuroscience
Type
Journal article