Phase of alpha rhythm and visually evoked potentials

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Fran Kirksey Deaton (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
M. Russell Harter

Abstract: The cortical excitability model proposed by Harter (1967) has, in part, been supported by findings in this experiment. The effects of alpha phase, flash intensity, and response task on visually evoked response amplitude, alpha blocking, and reaction time were investigated. The autostimulation technique was used to trigger light flashes, and the "resulting" evoked responses were averaged with a digital computer. Analyses of variance were performed to test for statistical significance on all data from one S. The amplitude of the visually evoked response was functionally related to alpha phase, flash intensity, and the interaction between these two variables (p < .01). Intensity significantly influenced early alpha blocking and reaction-time latency (p < .01). Two methods of data analysis were used. One method did not take an underlying averaged alpha into account, assuming alpha becomes desynchronized once blocked; the other took averaged alpha into account, assuming that alpha is ever-present but blanketed during photic stimulation. The appropriate model depended upon intensity in this study. High intensity stimulation supported the alpha-desynchronization model; low intensity stimulation supported the ever-present alpha model.

Additional Information

Language: English
Date: 1971
Alpha rhythm
Visual evoked response

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