Cerebral origins of the auditory projection to the superior colliculus of the cat.

Cerebral origins of the auditory projection to the superior colliculus of the cat.
Hear Res. 2013 Jun;300:33-45
Authors: Chabot N, Mellott JG, Hall AJ, Tichenoff EL, Lomber SG
Abstract
The superior colliculus (SC) is critical for directing accurate head and eye movements to visual and acoustic targets. In visual cortex, areas involved in orienting of the head and eyes to a visual stimulus have direct projections to the SC. In auditory cortex of the cat, four areas have been identified to be critical for the accurate orienting of the head and body to an acoustic stimulus. These areas include primary auditory cortex (A1), the posterior auditory field (PAF), the dorsal zone of auditory cortex (DZ), and the auditory field of the anterior ectosylvian sulcus (fAES). Therefore, we hypothesized that these four regions of auditory cortex would have direct projections to the SC. To test this hypothesis, deposits of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) were made into the superficial and deep layers of the SC to label, by means of retrograde transport, the auditory cortical origins of the corticotectal pathway. Bilateral examination of auditory cortex revealed that the vast majority of the labeled cells were located in the hemisphere ipsilateral to the SC injection. In ipsilateral auditory cortex, nearly all the labeled neurons were found in the infragranular layers, predominately in layer V. The largest population of label...

Source: Hearing Research - May 24, 2013 Category: Audiology Authors: Chabot N, Mellott JG, Hall AJ, Tichenoff EL, Lomber SG Tags: Hear Res Source Type: research