Evoked Potentials of the Midbrain Associated with the Beginning and End of a Sound of a Simple Tone

Abstract

The anatomical structure of the auditory system and the presence of several complementary levels of information processing allow a person to very quickly and accurately assess a variety of natural sounds that have minimal differences in frequency, duration, or intensity. At the same time, the features of the analysis of auditory information by the deep structures of the brain have not been fully investigated. In particular, the role of the midbrain in the perception of auditory information has not been fully identified. The basis of this study was the data of analysis of the activity of the midbrain in five people, obtained during intraoperative monitoring during surgery for the removal of tumor of the brainstem. Electric potentials were recorded using a depth electrode installed in the brain aqueduct. The activity of the midbrain associated with the response to simple tones was analyzed. Peaks S1, S2 and S3 were associated with the onset of the sound stimulus, peak E was associated with the end of the sound stimulus. Peaks S1, S2, and S3 most likely reflect the conduction of an uneven impulse along the auditory pathway. Peak E reflects the analysis of auditory information in the midbrain.