Calyx of Held Calyx of Held The Calyx of Held is a particularly large synapse in the mammalian auditory central nervous system, so named by Hans Held in his 1893 article "Die centrale Gehörleitung" because of its resemblance to the calyx of a flower. Globular bushy cells in the anteroventral cochlear nucleus (AVCN) send axons to the contralateral medial nucleus of the trapezoid body (MNTB), where they synapse via these calyces on MNTB principal cells. These principal cells then project to the ipsilateral lateral superior olive (LSO), where they inhibit postsynaptic neurons and provide a basis for interaural level detection (ILD), required for
Calyx of Held inhibitory effects. As a result of its role in stimulating the principal neurons, the primary function of the calyx of Held is to allow differentiation between temporal activation of the cochlear hair cells that are important in sound localization (interaural level detection). Interaural level detection is possible through the calyx system due to the large relative size of the GBCs, the calyx of Held, and the principal neurons. The neurons in the Lateral Superior Olive are especially important in discerning these interaural level changes. The large diameter size of the bushy cell axons allows the inhibitory signal produced by the