Magnus C. Petersen

Electroencephalographic rhythms from the depths of the parietal, occipital and temporal lobes in man ☆

Abstract Further studies have been done in an effort to establish additional patterns of the electric activity in the depths of the human brain. It has been demonstrated that somatic, sensory, motor, auditory and visual activity can be recorded from the depths of the brain. Synchronous activity recorded from the ventromedial part of the frontal lobe, parts of the temporal lobe, parts of the parietal lobe and the region of the hypothalamus indicates connections between these regions. Profound changes in the electric activity in these regions during acute episodes of agitation and hallucination have been observed.

Electroencephalographic rhythms from the depths of the frontal lobe in 60 psychotic patients.

Abstract The following waves were consistently recorded from the depths of the frontal lobes in 60 psychotic patients: (1) alphalike 8 to 12 c/sec. waves in the uppermost layers; (2) arrhythmic 2 to 4 c/sec. waves maximal in the ventral medial portions; (3) fast 25 c/sec. waves maximal in the lateral portions; (4) rhythmic 26 to 38 c/sec. waves from the olfactory bulb and (5) flat recordings, probably from the central white matter. Of 40 patients who had normal preliminary recordings from the scalp, 23 showed bilateral rhythmic bursts of high-voltage, 2 to 5 c/sec. waves, occasionally simulating slow sharp waves, in depth recordings. To allow assessment of the properties of the rhythms encountered in the depths of the frontal lobe, recordings were made under varied conditions, such as mental activity, hyperventilation, sleep, ether and barbiturate anesthesia, and various types of stimulation. Light ether anesthesia, as well as that induced by thiopental sodium, increased the voltage of the 25 c/sec. waves. Ether increased their frequency, whereas thiopental decreased it. Deep anesthesia further enhanced the changes in frequency. Evoked olfactory potentials were not abolished by deep anesthesia. Ether increased their frequency up to 48 c/sec. and thiopental sodium decreased it to 17 c/sec. We have attempted to contribute to the recognition and understanding of the wave forms in the frontal lobe and their distribution in the hope that such work will be of value in the establishment of base lines for depth electrography. As the recordings in this study were derived from psychotic patients, we have purposely avoided any statement regarding the normalcy of the waves described.

A multielectrode lead for intracerebral recordings

Abstract The various types of electrodes used for intracerebral recordings in human beings have been reviewed. A multielectrode lead is described which can be introduced into the brain externally to the needle-introducer. It can be used for recordings in the operating room as well as for “chronic” implantation (as “chronic” is defined herein). Localization of the tip of the electrode in the roentgenograms of the skull is fairly easy.

Technics and Potentialities of Intracranial Electrography

Intracranial electrography is an extension of scalp and surface electro-encephalography in which electric impulses are obtained from the depths of the human brain. The surgical technic required for the placement of deep electrodes is simple, and the multi-contact electrodes are well tolerated. Pertinent information may be obtained by means of electric recording from or stimulation of the subcortex. This method portends to become a valuable diagnostic and investigative aid.

INTRACEREBRAL ELECTROGRAPHIC STUDY OF 93 PSYCHOTIC PATIENTS 1

Il;lectro-encephalographic recording from electrodes on the scalp has given valuable information in the diagnosis and treatment of a number of neurologic disorders, such as brain injuries, brain tumors and epilepsy. However, the results have been rather disappointing with respect to mental disorders. On the other hand, recording from the depths of the brain by means of intracerebral microelectrodes has given valuable diagnostic, therapeutic and neurophysiologic information in patients suffering from mental disorders. It should be pointed out immediately that such examinations have been carried out only in connection with operations on the brain. The results of such recordings frequently have made it possible to limit substantially the final surgical operation.