Expertise shapes domain-specific functional cerebral asymmetry during mental imagery: the case of culinary arts and music.

Mental imagery in experts has been documented in visual arts, music and dance. Here, we examined this issue in an understudied art domain, namely, culinary arts. Previous research investigating mental imagery in experts has reported either a stronger involvement of the right hemisphere or bilateral brain activation. The first aim of our study was to examine whether culinary arts also recruit such a hemispheric pattern specifically during odor mental imagery. In a second aim, we investigated whether expertise effects observed in a given sensory domain transfer to another modality. We combined psychophysics and neurophysiology to study mental imagery in cooks, musicians and controls. We collected response times and event-related potentials (ERP) while participants mentally compared the odor of fruits, the timbre of musical instruments and the size of fruits, musical instruments and manufactured objects. Cooks were faster in imagining fruit odors, and musicians were faster in imagining the timbre of musical instruments. These differences were not observed in control participants. This expertise effect was reflected in the ERP late positive complex (LPC): only experts showed symmetric bilateral activation, specifically when cooks imagined odors and when musicians imagined timbres. In contrast, the LPC was significantly greater in the left hemisphere than in the right hemisphere for non-expert participants in all conditions. These findings suggest that sensory expertise does not involve transfer of mental imagery ability across modalities and highlight for the first time that olfactory expertise in cooks induces a balance of activations between hemispheres as does musical expertise in musicians.

Rhythmic auditory stimulation influences syntactic processing in children with developmental language disorders.

OBJECTIVE: Children with developmental language disorders have been shown to be impaired not only in language processing (including syntax), but also in rhythm and meter perception. Our study tested the influence of external rhythmic auditory stimulation (i.e., musical rhythm) on syntax processing in children with specific language impairment (SLI; Experiment 1A) and dyslexia (Experiment 1B). METHOD: Children listened to either regular or irregular musical prime sequences followed by blocks of grammatically correct and incorrect sentences. They were required to perform grammaticality judgments for each auditorily presented sentence. RESULTS: Performance of all children (SLI, dyslexia, and controls) in the grammaticality judgments was better after regular prime sequences than after irregular prime sequences, as shown by d' data. The benefit of the regular prime was stronger for SLI children (partial η2 = .34) than for dyslexic children (partial η2 = .14), who reached higher performance levels. CONCLUSION: Together with previous findings on deficits in temporal processing and sequencing, as well as with the recent proposition of a temporal sampling (oscillatory) framework for developmental language disorders (U. A. Goswami, 2011, Temporal sampling framework for developmental dyslexia, Trends in Cognitive Sciences, Vol. 15, pp. 3-10), our results point to potential avenues in using rhythmic structures (even in nonverbal materials) to boost linguistic structure processing.