Projections from the anteroventral cochlear nucleus to the lateral and medial superior olivary nuclei

Abstract

The projections from the cochlear nucleus to the lateral and medial superior olivary nuclei were studied in the cat by use of retrograde transport of horseradish peroxidase to demonstrate the connections. The medial superior olivary nucleus receives input only from the anterior and posterodorsal subdivisions of the anterior division of the anteroventral cochlear nucleus (AA and APD, respectively; Brawer, Morest, and Kane: J. Comp. Neurol. 155: 251-300, 1974). These two subdivisions are populated almost exclusively by spherical bushy cells. Like the medial superior olivary nucleus, the lateral superior olivary nucleus receives inputs from AA and APD. In addition, the lateral superior olivary nucleus receives projections from the posterior subdivision (AP) of the anterior division and also from the posterior division of the anteroventral cochlear nucleus. The projections to the medial superior olivary nucleus are bilateral, whereas the projections to the lateral superior olivary nucleus are almost entirely ipsilateral. One implication of the results is that the medial superior olivary nucleus receives inputs from only one cell type--the spherical bushy cell--but that, at the least, two cell types project to the lateral superior olivary nucleus. Both the olivary nuclei receive input from most, if not all, of the dorsoventral extent of the anteroventral cochlear nucleus, implying that both receive input from neurons arrayed across the entire frequency representation of the anteroventral cochlear nucleus. All of the projections appear to be organized topographically such that frequency representation is preserved.

Modeling Binaural Responses in the Auditory Brainstem to Electric Stimulation of the Auditory Nerve

“…The first stage is a phenomenological model of ANFs that produces realistic temporal discharge patterns to both acoustic pure tones and electric pulse trains (Nourski et al 2006). MSO neurons receive bilateral excitatory inputs from ANFs via spherical bushy cells (SBCs) in the VCN, as well as bilateral inhibitory inputs originating from globular bushy cells in the VCN (Cant and Casseday 1986;Smith et al 1993). In our implementation, the SBC stage was omitted because SBC shows little coincidence detection themselves (Wang and Delgutte 2012).…”

Subcortical processing in auditory communication

“…It is comprised of diverse and highly specialised neuronal populations (Ram on y Cajal c.1900;Lorente de N o, 1933Lorente de N o, , 1981 differing in morphology (Harrison and Warr, 1962;Osen, 1969a;and 1969b;Brawer et al, 1974;Heiman-Patterson and Strominger, 1985;Adams, 1986), response properties (Pfeiffer and Kiang, 1965;Pfeiffer, 1966;Evans and Nelson, 1973;Shofner and Young, 1985;Blackburn and Sachs, 1989;Winter and Palmer, 1990;Marsh et al, 2006), and connectivity with the auditory nerve (Liberman, 1991(Liberman, , 1993. Each neuronal population in the CN exhibits distinct projections (summarised in Cant and Benson, 2003), some ipsilateral (Cant and Casseday, 1986), others contralateral (Warr, 1966(Warr, , 1969Winer and Schreiner, 2005), reflecting the distinct functions of the CN anteroventral (involved in sound localisation) and posteroventral regions (involved in sound discrimination) (Eggermont, 2001).…”

Effects of Unilateral Acoustic Trauma on Tinnitus-Related Spontaneous Activity in the Inferior Colliculus

“…Type V units are binaurally excited (EE) and exhibit the "peak" binaural delay that is typically observed in the medial superior olive (MSO) Ramachandran and May 2002). Because spherical bushy cells (SBCs) in the anterior subdivision of the VCN project bilaterally to the MSO (Cant and Casseday 1986;Smith et al 1993), the dominant ascending inputs of type V units originate in the VCN.…”

“…Median SR is based only on spontaneously active units with BFs within two octaves of the EDGE suggest that their binaural responses are dictated by inputs from the lateral superior olive (LSO) (Ramachandran and May 2002). The LSO receives excitatory inputs from SBCs in the ipsilateral VCN (Cant and Casseday 1986;Cant and Benson 2003). Inhibitory inputs originate in the ipsilateral medial nucleus of the trapezoid body (MNTB) which are driven by globular bushy cells (GBCs) in the contralateral VCN (Kuwabara et al 1991;Smith et al 1991).…”