Averaged responses from association areas in waking cat

Abstract

Averaged cortical responses to click were studied in 39 adult cats. Records were made with implanted electrodes from the association areas of anterior lateral and posterior middle suprasylvian gyri, primary auditory area and primary visual area. In 31 animals electrodes were implanted under Nembutal anesthesia; in the other eight chloralose was used. In each of the 39 animals both referential and transcortical records made during waking and spontaneous sleep were compared with those made during chloralose anesthesia. In all but one animal association areas did not give rise to responses (transcortical recording) in the waking state even though responses appeared at the same sites during chloralose anesthesia. With referential recording potentials were recorded in association areas of all animals, but they were shown not to be generated locally. In the one exception, responses recorded during waking were augmented by chloralose anesthesia. In two animals, incompletely recovered from chloralose anesthesia, recordings were made repeatedly during alternate periods of “sleep” and “waking”. Results indicated that the dipole generating the response in the waking animal was different from the one giving rise to the response during sleep.