[Macro-electrode recording in man's brain-stem 1. Electrical activity during wakefulness and nightsleep (author's...

In the context of a functional treatment for pain five patients had electrodes chronically implanted in the periaqueductal gray matter (PGM) and at the same time in thalamic nuclei. The spontaneous activity of these structures was analyzed in comparison with the simultaneously recorded scalp-EEG. The structure-specific differences between the activity of the PGM and the thalamic nuclei were pointed out. In waking state a close functional relation between the alpha-activity of the PGM and the scalp-EEG was found. Physiological sleep patterns were recorded in the mesencephalon earleir than at the surface. REM-phases were initiated by 4/sec rhythms in the PGM. During rapid eye movements sharp waves in the PGM appeared which are evidently related to the eye movements themselves. The findings are discussed in reference to the literature. Special emphasis is placed on the anatomical connexions between the explored mesencephalic and thalamic structures and the temporo-occipital cortex and on the role of ponto-mesencephalic structures in slow-wave-sleep and REM-sleep.