1977 Volume 2 Issue 3 Pages 136-144
In order to control the size of marking spot in cerebral cortex, a new electrolytic method was improved and the rectangular current (1 Hz, 0.5sec. duration) was supplied by a constant current isolator. This technique indicates that the polarizing effect occured at the tip of tungsten microelectrode was much less than the ordinary method. Inserting the microelectrodes into the cortices, the electrolytic lesions were made by the several current flows in vivo. The relationship between the spot size (μm2) measured histologically and quantity of electricily (coulomb) supplied through the electrode was determined systematically. Within some current range, the marking spots varied proportionally in diameter with increase in quantity of electricity and the range of optimum quantity was 12×10-6 to 15×10-6 coulomb. After the single neuron which responded to the tooth pulp stimulation was detected electro-physiologically, the rectangular current of 12×10-6 coulomb was supplied to make a micro-lesion for histological identification.
Then the location of the neuron was pursued microscopically and the spot dyed by Nissl method showed that the identified neuron was located at the deep layer of lamina III in the middle part of anterior suprasylvian gyrus.
