Auditory cortical axons contact commissural cells throughout the guinea pig inferior colliculus.

Auditory cortical axons contact commissural cells throughout the guinea pig inferior colliculus.
Hear Res. 2013 Oct 17;
Authors: Nakamoto KT, Sowick CS, Schofield BR
Abstract
Projections from auditory cortex (AC) affect how cells in both inferior colliculi (IC) respond to acoustic stimuli. The large projection from the AC to the ipsilateral IC is usually credited with the effects in the ipsilateral IC. The circuitry underlying effects in the contralateral IC is less clear. The direct projection from the AC to the contralateral IC is relatively small. An unexplored possibility is that the large ipsilateral cortical projection contacts the substantial number of cells in the ipsilateral IC that project through the commissure to the contralateral IC. Apparent contacts between cortical boutons and commissural cells were identified in the left IC after injection of different fluorescent tracers into the left AC and the right IC. Commissural cells were labeled throughout the left IC, and many (23-34%) appeared to be contacted by cortical axons. In the central nucleus, both disc-shaped and stellate cells were contacted. Antibodies to glutamic acid decarboxylase (GAD) were used to identify GABAergic commissural cells. The majority (>86%) of labeled commissural cells were GAD-immunonegative. Despite low numbers of GAD-immunopositive commissural cells, some of these cells were contacted by cortical boutons. Nonetheless, most cortically contacted commi...

Source: Hearing Research - October 17, 2013 Category: Audiology Authors: Nakamoto KT, Sowick CS, Schofield BR Tags: Hear Res Source Type: research