IN ORDER to set the stage for a study of aphasia, we record here certain observations in regard to (a) vocalization as a response to stimulation of the human cerebral cortex and (b) arrest of speech by means of stimulation. We have supplemented these observations with limited reference to the effect of excision of areas of the sensorimotor convolutions in the dominant or the nondominant hemisphere.
In 1935, as the result of using a thyratron physiologic stimulator on the precentral gyrus of a man with local anesthesia, one of us (W. P.) was surprised by a clear, sustained vowel cry. After the electrode was withdrawn, the patient observed that something had made him speak.Repeated stimulation in a small zone limited to a few millimeters reproduced the sound over and over again. If stimulation was prolonged, it continued until breath was exhausted, whereupon the patient took a breath and
PENFIELD W, RASMUSSEN T. VOCALIZATION AND ARREST OF SPEECH. Arch NeurPsych. 1949;61(1):21-27. doi:10.1001/archneurpsyc.1949.02310070027002