Figure 6: Cross-frequency spectrum of brain oscillations during a motor task.
From: In vivo assessment of human brain oscillations during application of transcranial electric currents
Cross-frequency spectrum of self-paced left index finger button press-related signal source changes in the primary motor cortex (M1) in absence (left) and during (middle) electric stimulation across all participants (a–e). Note the typical motor task-related changes of signal power in alpha (8–13 Hz) (alpha desynchronization shortly before and after button press; most prominent in participants 2 and 4) and beta (13–30 Hz) (beta synchronization approximately one second after the button press) as described by Pfurtscheller and Aranibar37 and others. Frequency spectra of MEG activity during task-free intervals (right) exhibit the typical physiologic alpha and beta peaks, and indicate no stimulation specific distortions in other frequencies.
