The long-term objective is to understand the organization of the brainstem auditory pathways in terms of connections among the multiple neuronal types that form them. The objective of the proposed studies is an analysis of the termination patterns of specific cell types projecting into and out of the inferior colliculus (IC) of the gerbil. Nine experiments are proposed to achieve three specific aims: 1) To further characterize a) the multipolar cell pathway(s) from the ventral cochlear nucleus to the IC and b) the fusiform and giant cell pathways from the dorsal cochlear nucleus to the IC; 2) To determine the extent to which the descending projections from the auditory cortex to the IC overlap with ascending projections from the superior olivary complex versus those from the cochlear nuclei; 3) To determine whether different collicular domains give rise to projections to different parts of the medial geniculate nucleus. The working hypothesis that unites the specific aims is that zones in the inferior colliculus can be identified which are the targets of specific subsets of the ascending pathways and, further, that these zones project differentially into the forebrain. Neuroanatomical methods to be employed include techniques based on the anterograde and/or retrograde axonal transport of various tracer molecules; immunocytochemistry, and histochemistry. Neuroanatomical studies such as the ones proposed provide information essential for reaching an understanding of the mechanisms of auditory processing. The neuronal activity that leads to functional expression is dependent on the precise and specific connections among the hundreds of specialized neuronal types which collectively form the auditory system. Detailed understanding of these connections will not only help to explain available functional data, they will also provide a basis for developing rational hypotheses about auditory function that can be tested further.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC000135-26
Application #
6860082
Study Section
Special Emphasis Panel (ZRG1-IFCN-6 (01))
Program Officer
Platt, Christopher
Project Start
1978-07-01
Project End
2008-03-31
Budget Start
2005-04-01
Budget End
2008-03-31
Support Year
26
Fiscal Year
2005
Total Cost
$289,520
Indirect Cost
Name
Duke University
Department
Biology
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Cant, Nell B (2013) Patterns of convergence in the central nucleus of the inferior colliculus of the Mongolian gerbil: organization of inputs from the superior olivary complex in the low frequency representation. Front Neural Circuits 7:29
Cant, N B; Benson, C G (2008) Organization of the inferior colliculus of the gerbil (Meriones unguiculatus): projections from the cochlear nucleus. Neuroscience 154:206-17
Cant, Nell B; Benson, Christina G (2006) Organization of the inferior colliculus of the gerbil (Meriones unguiculatus): differences in distribution of projections from the cochlear nuclei and the superior olivary complex. J Comp Neurol 495:511-28
Schofield, B R; Cant, N B (1999) Descending auditory pathways: projections from the inferior colliculus contact superior olivary cells that project bilaterally to the cochlear nuclei. J Comp Neurol 409:210-23
Schofield, B R; Cant, N B (1997) Ventral nucleus of the lateral lemniscus in guinea pigs: cytoarchitecture and inputs from the cochlear nucleus. J Comp Neurol 379:363-85
Schofield, B R; Cant, N B (1996) Projections from the ventral cochlear nucleus to the inferior colliculus and the contralateral cochlear nucleus in guinea pigs. Hear Res 102:1-14
Schofield, B R; Cant, N B (1996) Origins and targets of commissural connections between the cochlear nuclei in guinea pigs. J Comp Neurol 375:128-46
Schofield, B R; Cant, N B (1992) Organization of the superior olivary complex in the guinea pig: II. Patterns of projection from the periolivary nuclei to the inferior colliculus. J Comp Neurol 317:438-55
Schofield, B R; Cant, N B (1991) Organization of the superior olivary complex in the guinea pig. I. Cytoarchitecture, cytochrome oxidase histochemistry, and dendritic morphology. J Comp Neurol 314:645-70
Schofield, B R (1991) Superior paraolivary nucleus in the pigmented guinea pig: separate classes of neurons project to the inferior colliculus and the cochlear nucleus. J Comp Neurol 312:68-76