[Glial origin of negative shifts in the surface potential of the brain upon tetanic stimulation: microelectrode study and mathematical analysis].

It is shown in experiments on anesthetized cats that negative shift of the cortical surface potential evoked by its tetanic stimulation is similar in form and time course to the depolarization of glial cells. On the contrary, hyperpolarizing shifts of neuronal membrane potential are dissimilar in form and time course to the negative shift of the cortical surface potential. A conclusion is made that the contribution of neuronal hyperpolarization to the surface-negative shift of the potential can distinctly be seen only at the beginning of tetanization--in the first 200-300 ms; negative shift of the cortical surface potential is mainly produced by depolarization of glial cells.