EEG patterns suggestive of shifted levels of excitation effected by hathayogic exercises

Concurrent with the performance of hathayogic exercises such as Nauli, Bhastrika and Suryabhedana, three characteristic EEG patterns were identified: a 'wicket' rhythm at a frequency wave of 12 to 17 Hz, recordable from para-Rolandic areas, which we have called Xi rhythm; a 26-33 Hz sinusoidal activity, confined to the mid-sagittal parietooccipital region; and paroxysmal activity localized in the lateral boundaries of parieto-temporo-occipital regions, bilaterally. - The expectation that hathayogic exercises would affect the electrical activity of circumscribed, relatively well defined areas of the brain was based on the fact that these exercises imply a strong stimulation of somatic and splanchnic receptors, the afferent impulses of which are fed into specific cortical representation areas localized for the most part around central and anterior parietal areas.