Figure 2 Electrical responses of central nucleus of the inferior colliculus (CNIC) neurons in the control group to paired sound stimuli at different azimuths. The regular spike trials evoked by paired stimuli (50 ms inter-stimulus delay [ISD]) in CNIC neurons are presented in the pattern of leading-lagging: contralateral-ipsilateral 18° (A). Local zoom of the leading and lagging sounds evoked potentials is shown at contralateral-ipsilateral 18° and ipsilateral-contralateral 18° (B). Histograms of 100 responses from 16 channels of 1 rat are presented at contralateral 18°-ipsilateral 18°, ipsilateral 18°-contralateral 18°, contralateral 45°-ipsilateral 45°, and ipsilateral 45°-contralateral 45°(C). Mean normalized neuronal responses of the CNIC neurons to paired stimuli are illustrated at contralateral 18°-ipsilateral 18° and ipsilateral 18°-contralateral 18°; contralateral 45°-ipsilateral 45° and ipsilateral 45°-contralateral 45° (D). The bold black arrows represent the start of recording, the bold red arrows show the onset of the sound, and the bold blue arrows represent the offset of the sound. The thin red arrows represent 1 acoustic stimulus. The green arrows show the lagging sound evoked spike clusters. Dotted line refers to half-maximal ISDs. The data are expressed as the SEM. n=5; * P<0.05, ** P<0.01, *** P<0.001.