Effects of focused ultrasound on spontaneous cortical electrical potentials of the cat

¹ Department of Neurological Surgery, New York University Medical School, New York City

An area several millimeters square in the frontal, the parietal, or the occipital regions of the cat's brain was irradiated with focused ultrasound. The spontaneous electrical cortical potentials seen under barbiturate anesthesia were reversibly depressed over one or both cerebral hemispheres. The depression of cortical activity was of greater duration and more severe after multiple irradiations. Larger total dosages produced by longer periods of multiple irradiations, evoked only in the frontal area, generalized fast electrical epileptic cortical activity. If this activity was of high amplitude, tonic tremor seizures appeared, but no clonic component developed.