A reference handbook of the medical sciences, embracing the entire range of scientific and practical medicine and allied science . esponse, are applied to themotor cortex at intervals of aboutthirty seconds a slight reaction isobtained after a few stimuli, and ifthe stimuli are continued, the reac-tions increase in intensity. Follow-ing this kind of stimulation themuscles return to their normal con-dition, sometimes, however, onlyafter passing through a stage ofclonic epileptiform movements. Thisphenomenon is of special interest be-cause of its relation to the hypothesisof the genesis of corti
A reference handbook of the medical sciences, embracing the entire range of scientific and practical medicine and allied science . esponse, are applied to themotor cortex at intervals of aboutthirty seconds a slight reaction isobtained after a few stimuli, and ifthe stimuli are continued, the reac-tions increase in intensity. Follow-ing this kind of stimulation themuscles return to their normal con-dition, sometimes, however, onlyafter passing through a stage ofclonic epileptiform movements. Thisphenomenon is of special interest be-cause of its relation to the hypothesisof the genesis of cortical epilepsy. When supraliminal stimuli are ap-plied to the motor cortex at a slowrate, let us say one per second, eachstimulus is accompanied by its ownmotor response, which has the na-ture of a small contraction. When the stimuli arerapidly repeated, the innervated muscles respondwith a tetaniform contraction, which may be moreor less complete according to the rapidity of therepeated shocks. If the stimuli are very rapid, onehundred or more per second, the muscles respond—as shown by the contraction curves, by the muscle. Fig. 1034.—Histological (Cj-toarchitectonic and Myeloarchitectonic) Differentiationof Cortical Areas on the Mesial Aspect of the Human Brain. (After Brodmann.) tone, and by the electrical variations—by contractionscorresponding to a rate of stimulation from ten tofourteen per second. The more rapid stimulationsto the cortex, and equally so to the fibers of the coronaradiata, are apparently transformed either in the 400 REFERENCE HANDBOOK OF THE MEDICAL SCIENCES Brain, Physiology of cortical cells, or in those of the spinal cord to thelower rate. A similar transformation from the con-tinued stimuhilion of a mechanical character has beenobserved; and this fact also is interesting in relationto the production of epileptiform convulsions bypressure upon the cortex. Some investigators have doubted the possibility ofstimulation of the brain by mechanical mea
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