Olivocochlear system
![The mammalian olivocochlear bundle, divided into medial (red) and lateral (green) systems. Both contain crossed and uncrossed fibres. The predominant fibres are represented by a thicker line. The insert (far left) shows the position of the cell bodies of the MOCS and LOCS relative to the MSOC and LSOC respectively, as observed in mammals.](/Images/godic/202501/30/Diagram_of_the_olivocochlear_bundle2932.jpg")
![Attentional filter depths from 12 subjects who underwent a vestibular neurectomy, for the same ear (triangles) or different ears (crosses). Combined mean (----) and 95% confidence intervals are shown. An average ~15% decline in attentional filter depth can be seen following olivocochlear bundle (OCB) lesion. Data taken from Scharf et al. (1997).[26]](/Images/godic/202501/30/Scharfs_OCB_experiments32932.jpg")
The olivocochlear system is a component of the auditory system involved with the descending control of the cochlea. Its nerve fibres, the olivocochlear bundle (OCB), form part of the vestibulocochlear nerve (VIIIth cranial nerve, also known as the auditory-vestibular nerve), and project from the superior olivary complex in the brainstem (pons) to the cochlea.