Auditory evoked potentials recorded from chronic implanted gyrus of Heschl in man

By means of implanted multileads electrodes, responses to clicks and prolonged sound stimulations were recorded from the Heschl gyrus of 2 human brains. These responses were strictly localized to this structure. Cortical averaged auditory evoked potentials (c.AEP) to clicks are consistent with scalp averaged auditory evoked potentials (s.AEP). So, Na Pa, Nb, P1, N1, waves have similar latencies and none of them in the s.AEP may be correlated with myogenic potentials (in opposition with the suggestions of Bickford et al. 1964 and Celesia et al. 1968). Increasing the duration of sound stimulation resulted in changes of the response. For a duration longer than 20ms, an "on-response" and an "off-response" were noted. No satisfying physiological explanation of these events is retained despite data obtained with monaural homo and heterolateral stimulations and with variation of tone of sound stimulation.