SOUND CORRELATED D-C CHANGES IN PRIMARY AUDITORY CORTEX OF AWAKE CAT

Sound evoked d-c changes in the primary auditory cortex (CGA= corticale Gleichspannungsantwort) of the cat were recorded with subdural implanted Ag-AgCl electrodes and analysed with a LINC-8-Computer. The CGA were maintained for the whole duration of stimulus, they depend on the stimulus quality (e.g. tone frequency), on the level of anesthesia and on the stimulus intensity. The intensity function (relation between CGA amplitude and stimulus intensity) has been investigated. It is characterised by the rising coefficient of the approximating line in dependence of the time of analysis (time of analysis starts with the stimulus beginning) with respect to correlation. The rising coefficient n varies with the time of analysis. Whereas in the first second it varies between the values 0.7 and 0.4 it tends with increasing time of analysis to 0.3. © 1969 Springer-Verlag.