Conditioned interhemispheric transfer by cerebral tetanization

Electrodes were implanted over the motor and occipital cortex in both cerebral hemispheres of five dogs and also over the right ectosylvian cortex in one dog. Stimulation of these areas resulted mainly in contralateral movements opposite to the stimulated cortex. At appropriate voltages, stimulation of the occipital and ectosylvian cortex resulted in no movement at all. A non-motivated conditioned reflex (CR) was elaborated by coupling electrical stimulation of the occipital (CS) and the ipsilateral motor cortex (US). After long-term consolidation of this CR, electrical stimulations of the opposite hemisphere were performed again and a complete interhemispheric transfer was observed in all five dogs, i.e., stimulation of either right or left occipital cortex as well as stimulation of the right or left motor cortex constantly resulted in the same movement. The dynamics of the interhemispheric transfer were different in each individual dog. The transfer was limited to the symmetrical motor and occipital cortex. Stimulation of the ectosylvian cortex never resulted in any movement. This interhemispheric transfer is discussed as a function of the previous experience of the animal.