Information processing of the long-lasting sustained activities in rat auditory cortex

Abstract

To date, auditory neural systems have been thought to be sensitive to rapid change of sensory input, thus the long-lasting sustained activities after the transient activities responding to sound onset has been ignored. In this study, we targeted rat auditory cortex and attempted to reveal that the sustained activities represent not only sound frequency, but sound-associated emotion and sound texture. A microelectrode array with 96 recording sites recorded sound-responding local field potentials from the auditory cortex of anesthetized rats, and we calculated phase locking values (PLVs). First, machine learning demonstrated that PLV patterns represent the sound frequency tonotopically. Second, not appetitive, but aversive classical conditioning strengthened PLV in the specific band. Lastly, texture of the chord, e.g., consonant/dissonant chord and major/minor chord, differently affected PLV. These results suggest that the sustained activities may strongly contribute to further analysis of the sound in the auditory cortex.