title: Fast and persistent adaptation to new spectral cues for sound localization suggests a many-to-one mapping mechanism.
abstract: The adult human auditory system can adapt to changes in spectral cues for sound localization. This plasticity was demonstrated by changing the shape of the pinna with earmolds. Previous results indicate that participants regain localization accuracy after several weeks of adaptation and that the adapted state is retained for at least one week without earmolds. No aftereffect was observed after mold removal, but any aftereffect may be too short to be observed when responses are averaged over many trials. This work investigated the lack of aftereffect by analyzing single-trial responses and modifying visual, auditory, and tactile information during the localization task. Results showed that participants localized accurately immediately after mold removal, even at the first stimulus presentation. Knowledge of the stimulus spectrum, tactile information about the absence of the earmolds, and visual feedback were not necessary to localize accurately after adaptation. Part of the adaptation persisted for one month without molds. The results are consistent with the hypothesis of a many-to-one mapping of the spectral cues, in which several spectral profiles are simultaneously associated with one sound location. Additionally, participants with acoustically more informative spectral cues localized sounds more accurately, and larger acoustical disturbances by the molds reduced adaptation success.
authors: International Laboratory for Brain, Music and Sound Research (BRAMS), Department of Psychology, Université de Montréal, Pavillon 1420 Boulevard Mont-Royal, Outremont, Quebec, H2V 4P3, Canada.
authors: Régis
authors: R
authors: Trapeau
authors: International Laboratory for Brain, Music and Sound Research (BRAMS), Department of Psychology, Université de Montréal, Pavillon 1420 Boulevard Mont-Royal, Outremont, Quebec, H2V 4P3, Canada.
authors: Valérie
authors: V
authors: Aubrais
authors: International Laboratory for Brain, Music and Sound Research (BRAMS), Department of Psychology, Université de Montréal, Pavillon 1420 Boulevard Mont-Royal, Outremont, Quebec, H2V 4P3, Canada.
authors: Marc
authors: M
authors: Schönwiesner