EEG theta synchronization conjoined with alpha desynchronization indicate intentional encoding.
The involvement of different oscillating neuronal systems activated during intentional learning was investigated by measuring ongoing EEG activity. In 17 subjects, the EEG was recorded while learning pairs of words and faces. Subjective task difficulty was rated and a control condition of mental relaxation was also run. Spontaneous EEG activity during epochs which subsequently resulted in efficient encoding was associated with upper alpha desynchronization (10-12 Hz) and theta synchronization (4-8 Hz) when compared with spontaneous EEG activity during epochs of poor recall performance. The combined measure of theta synchronization plus upper alpha desynchronization was enhanced selectively over left frontotemporal cortical regions during efficient learning of words and over right parietal cortical regions during efficient learning of faces (P < 0.001). This striking topographical dissociation between learning materials for the combined measure of theta and upper alpha EEG activity suggests that the mode of intentional learning relies essentially on an interdependent regulation of two neuronal circuits: the thalamo-cortical circuit and the hippocampo-cortical circuit.
Mölle
Matthias
M
Department of Clinical Neuroendocrinology, Medical University of Lübeck, Ratzeburger Allee 160, Haus 23a, 23538 Lübeck, Germany. moelle@kfg.mu-luebeck.de
Marshall
Lisa
L
Fehm
Horst L
HL
Born
Jan
J
D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000513:Alpha Rhythm; D001683:Biological Clocks / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology; D003344:Cortical Synchronization; D005133:Eye Movements / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D007858:Learning / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D016548:Prosencephalon / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D013788:Thalamus / Q000502:physiology; D013826:Theta Rhythm; D014705:Verbal Behavior / Q000502:physiology; D014836:Volition / Q000502:physiology