Behavioral correlates of Zwicker tone percepts in rodents
Achim Schilling1, Konstantin Tziridis1, Holger Schulze1, Patrick Krauss1; 1Experimental Otolaryngology, Neuroscience Group, University Hospital Erlangen, University of Erlangen-Nuremberg
Subjective tinnitus is an auditory phantom percept in the absence of any physically present sound source which often causes severe psychological stress. Unfortunately, the underlying cognitive mechanisms are still not fully understood. An interesting model for acute tinnitus is the Zwicker tone percept, as recent models suggest that underlying neural mechanisms are similar. The Zwicker tone is an auditory phantom percept which e.g. may be induced by the presentation of noise stimuli with a spectral notch, leading to the transient perception of a pure tone in the range of the notched frequency band for several seconds after the end of the stimulation. To analyze the neurophysiological mechanisms leading to the perception of a Zwicker tone, the usage of an animal model would be desirable. However, still no behavioral paradigms are available to objectively prove the presence of a Zwicker tone percept in animal models. Here we use the effect of a modified gap pre-pulse inhibition of the acoustic startle reflex (GPIAS; introduced by Turner in 2006) testing the possibility of inducing a Zwicker tone percept in our animal model (Mongolian gerbil). We present a 60 dB SPL notched noise stimulus with a silent gap 100 ms before a loud startle stimulus. We demonstrate that a Zwicker tone percept within this gap leads to an increased pre-pulse inhibition as the phantom percept itself may serve as pre-stimulus which modulates the startle reflex amplitude. The here described paradigm demonstrates that Mongolian gerbils are able to perceive the Zwicker tone.
Topic Area: PERCEPTION & ACTION: Audition