Abstract
Latencies to dichotic tones presented either alone or with noise masking were obtained from ten rats before and after surgery. The crossed olivocochlear bundle (COCB) was cut in five animals, but left intact in control subjects. COCB sectioned animals differed from Sham controls only when the tones were masked by noise. The two groups did not not differ (a) in masked or unmasked threshold estimates, or (b) in unmasked loudness functions computed from latency data. Masked loudness functions from COCB sectioned animals exhibited recruitment from unchanged masked thresholds, and saturated within 30 dB. At saturation, masked tones were louder than unmasked tones (latencies were shorter). The lack of effect in the absence of masking agrees with Dewson [J. Neurophysiol. 31, 122–130 (1968)]. These results support the concept of a negative feedback system mediated by COCB neurons, but which may only operate in the presence of broadband input. COCB activity may reduce the gain at the periphery, with an improvement in the dynamic range of the system under masking being the result. [Work supported by USAF.]
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
