EEG correlates of verbal learning and overlearning

The findings suggest that EEG desynchronization occurs during the active phase of learning, consistent with a previous experiment on verbal learning and in general agreement with the literature on conditioning.

Abstract

Variations in EEG activity were investigated during the learning and overlearning of verbal material. Seventeen college students learned twelve nonsense syllables presented orally by the serial anticipation method, followed by an additional 20 trials of overlearning. Simultaneous parieto-occipital tracings were recorded with eyes closed, and evaluated by means of a modified Burch Period Analyser. The number of waves per unit of time was determined for three frequency bands: beta (> 12.5 c/sec), alpha (8.5–12.5 c/sec), and slow (< 8.5 c/sec). Wave counts of the differentiated pattern (first derivative) gave an index of superimposed, low voltage fast activity. Significant EEG changes were obtained during verbal learning as opposed to nonlearning control conditions. Whereas alpha activity decreased during learning, beta and superimposed activity increased. These changes were maximal at a critical time in the learning process; i.e., when syllables were first being anticipated correctly. Overlearning resulted in a slight return of the tracing toward control levels, but this trend was not significant. The findings suggest that EEG desynchronization occurs during the active phase of learning. They are consistent with a previous experiment on verbal learning and are in general agreement with the literature on conditioning. The results were discussed in the light of recent theories concerning the functional significance of the reticular activating system.