Poster D103, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
Effects of a tinnitus percept on tone discrimination learning in Mongolian Gerbils
Achim Schilling1, Patrick Krauss1, Konstantin Tziridis1, Ilona Strohmeyer1, Holger Schulze1; 1University of Erlangen-Nuremberg
The mechanisms of the chronic manifestation of central tinnitus are still not completely understood, but do involve plastic changes of the functional organization of the auditory cortex (AC). Here we investigate possible interferences of tinnitus related maladaptive plastic AC changes with tone discrimination learning plasticity in Mongolian gerbils. 12 animals (trauma group) were treated with a mild acoustic trauma (2kHz, 115 dB SPL, 75 min), 6 animals (control group) received sham trauma (2 kHz, 65 dB SPL, 75 min). Starting two days after the acoustic event, the animals were trained over 10 days with a pure tone discrimination learning paradigm (2 vs. 5 kHz aversive GO-NOGO shuttle-box paradigm). Approximately 60% of the trauma group animals developed a tinnitus percept (T) while in the remaining 40% no tinnitus percept was detectable (NT) (behaviorally tested: gap/nogap startle-paradigm). A group comparison between control and the T group showed no significant differences in the learning performance, but the learning performance of the NT group turned out to be significantly impaired. On the other hand, an individual analysis of learning performance revealed that T animals with tinnitus frequencies at or above the training frequency used in the range learning paradigm also showed a significantly impaired learning performance. This observation is an indication of an interferences of the plastic changes induced by tinnitus and learning, respectively. The impaired learning performance of the NT animals might either be an effect of the trauma induced hearing loss or an effect of the trauma induced reduction of cortical activity.
Topic Area: PERCEPTION & ACTION: Audition