Auditory deviance detection in the human insula: An intracranial EEG study

While the human insula is known to be involved in auditory processing, knowledge about its precise functional role and the underlying electrophysiology is limited. To assess its role in automatic auditory deviance detection we analyzed the high frequency EEG activity (75-145 Hz) from 90 intracranial insular electrodes across 16 patients who were candidates for resective epilepsy surgery while they passively listened to a stream of standard and deviant tones. Deviant and standard tones differed in four physical dimensions: intensity, frequency, location and time. Auditory responses were found in the short and long gyri, and the anterior, superior, and inferior segments of the circular sulcus of the insular cortex, but only a subset of electrodes in the inferior segment showed deviance detection responses, i.e. a greater and later response to deviants relative to standards. Altogether, our results indicate that the human insula is engaged during auditory deviance detection.