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Abstract

The investigation of expert behaviors in fMRI is of considerable interest to cognitive neuroscientists. However, for some skilled motor behaviors, the physical constraints of the MRI scanner often mean that the expertise can only be measured indirectly (e.g. visual observation of dance; Calvo-Merino et al., 2005), or using restrictive simulations (e.g. simple keypads for pianists; Baumann et al., 2007). An additional problem is how to select control groups and tasks for some of these highly specialized outputs. In contrast, speech production can be performed naturally in fMRI and is an expert skill for normal adults. Professional voice artists are additionally skilled in this capacity and work in a variety of settings that require expert manipulation of the voice, for example performing impressions of famous individuals, or providing voices for cartoon characters. As part of a larger study of vocal expertise, we collected fMRI data from a group of non-expert participants while they performed vocal impersonations of familiar individuals and accents of English. Changing the voice during impersonations gave increased activation in left-lateralized areas for speech motor planning and production, and in left temporal cortex. Comparing the two impersonation conditions showed increased activation of visual and somatosensory cortex when participants attempted to impersonate a specific individual, as opposed to a generic accent. These results suggest that impersonating a familiar individual’s speech involves stronger visual imagery (Ishai et al., 2002) and monitoring of somatosensory feedback from the articulators (Dhanjal et al., 2008) in the attempt to generate a specific non-self target voice.