Auditory response areas altered by intermodulation distortion products from background tones.
Response areas (RAs) of sensory neurones are dynamically modified by attention, denervation of specific afferent input, blocking inhibition, and by prolonged conditioning with extra-RA stimuli. Here we demonstrate in auditory neurones that the RA is also critically influenced by the background to stimuli. When RAs are measured in the presence of non-excitatory extra-RA tones, new RAs arise at frequencies otherwise not excitatory, as a consequence of non-linear receptor organ transduction. The new RAs can become more sensitive than the RA in quiet conditions such that neurones are then effectively tuned to a new frequency. Thus, even in a modestly complex environment, auditory neurones do not signal a fixed range of sounds but effectively code sounds to which they are otherwise unresponsive.
Rajan
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Department of Physiology, Monash University, Victoria, Australia.
D000161:Acoustic Stimulation; D000818:Animals; D001306:Auditory Pathways / Q000502:physiology*; D002415:Cats; D017626:Cochlear Nucleus / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D017711:Nonlinear Dynamics; D011930:Reaction Time / Q000502:physiology