Posttetanic potentiation of primary response and late negative wave in the somatosensory region of the cortex of the cat.

The experiments were carried out on cats under nembutal anesthesia. Stimulation of the ventroposterolateral nucleus of the thalamus or the white matter by a single stimulus elicited a primary response in the middle layers of the somatosensory cortex, and after it, a late negative wave, the duration of which reaches 40-70 msec. This potential does not have dipole reflection on the surface of the cortex and is apparently generated primarily by stellate cells. As a result of the tetanization of the ventroposterolateral nucleus or the white matter, a sharp increase in the amplitude of the late negative wave is observed, i.e., its posttetanic potentiation, while the primary response changes to a significantly lesser degree. Posttetanic potentiation is observed for 2-2.5 h. Posttetanic potentiation of the late negative wave is probably governed by processes occurring at the level of the middle layers of the cerebral cortex.