Studies on the human spontaneous electromyelogram (EMycloG). I. Normal subjects.

Using an intrathecal recording technique, the spontaneous electrical activity (EMyeloG) of the spinal cord was recorded in 25 normal human subjects. Very fast, continuous, irregular activity was analysed from the lumbo-sacral or cervical enlargement of the spinal cord after excluding volume-conducted potentials such as ECG and EMG. It was demonstrated that these spontaneous action potentials could be divided into two basic groups: (a) negative-positive diphasic waves, and (b) positive monophasic or positive-negative diphasic waves. Both waves were less than 50 microV and shorter than 10 msec. Their discharge rates were irregular, changing from time to time and from case to case. It is proposed that these spontaneous EMyeloGs recorded from normal human subjects are similar to those of 'background activity' described in the cat. Therefore they may share the same origin.