Changes in two EEG rhythms during mental activity.

Abstract

2 sets of tasks-mental addition tasks and concept tasks-were given to 12 Ss and the effects of these tasks on 2 EEG rhythms-kappa and alpha-observed. On the mental addition tasks the difficulty of the task was shown to increase the output of kappa significantly but not the output of alpha. On the concept task, however, the difficulty of the task was shown to depress the output of alpha significantly. The results for kappa, although highly consistent for each individual, did not show any consistent pattern from one individual to another. It is suggested that the effects of mental tasks on kappa and alpha are specific to the sense modality involved in the task.

Consciousness and Self-Regulation

“…Several subsequent studies seemed to demonstrate a clear relationship between mental tasks themselves and the blocking of alpha activity in the EEG (Chapman, Armington, and Bragdon, 1962;Darrow, Vieth, and Wilson, 1957;Glanzer, Chapman, Clark, and Bragdon, 1964;Glass, 1964Glass, , 1967Lorens and Darrow, 1962). We also found, in early studies, that combining the task of incrementing alpha through feedback with a cognitive task such as subtracting by sevens produced more alpha blocking.…”

The relationship of theory and methodology in EEG studies of mental activity

“…This could explain prominent non-specific changes in the EEG during mental activity such as the alpha rhythm desynchronization that accompanies the orienting reaction or voluntary attention (Lindsley, 1960;Sokolov, 1963;Glanzer et al, 1964). These findings laid the foundation for the basic psychophysiological theory of the functional states of the brain.…”

“…The comparative topography of this reaction, when comparing and contrasting intellectual and motor tasks (Lazarev, 1987(Lazarev, , 1992(Lazarev, , 1998a, was similar to that observed in our experiments with spatial synchronization of biopotentials (Lazarev et al, 1977;Lazarev, 1978) and alpha rhythm desynchronization (Lazarev, 1992). All these changes included as a main part a reaction of EEG desynchronization, widely recognized as the expression of the brain's activation (Glanzer et al, 1964;Pfurtscheller et al, 1988). This clearly testified that Factor I reflects the same non-specific activation processes, referred to above as 'general activation,' displaying relative consistency with all three measuring methods (Lazarev, 1992).…”