Best Frequency-Shift of Collicular Neurons Induced by Real-Time Interaction between Inferior Colliculi via Intercollicular Commissural Projections

The left and right inferior colliculus (IC) are interconnected with each other by the commissure of inferior colliculus (CoIC). So far, little has been known about its role in the auditory information processing and integration between the two ICs in real time. In this study, we examined the changes in the best frequency (BF) of neurons in one side IC (ICRec) during activation of CoIC by focal electrical stimulation (ES) of the opposite IC (ICES). Results showed that during ES of ICES, the BFs of 38 (38/70, 54.3%) ICRec neurons were changed and the range of BF shift in 31 among 38 (31/38, 81.6%) ICRec neurons was between 0~2 kHz. In addition, the BF shift of ICRec neurons evoked by ES of ICES increased with the increasing of BF difference between the ICRec and ICES neurons. These suggested that intercollicular interaction played perhaps a role in the sound processing and integration between ICs.