Aside from spoken language, singing represents a second mode of acoustic (auditory-vocal) communication in humans. As a new aspect of brain lateralization, functional magnetic resonance imaging (fMRI) revealed two complementary cerebral networks subserving singing and speaking. Reproduction of a non-lyrical tune elicited activation predominantly in the right motor cortex, the right anterior insula, and the left cerebellum whereas the opposite response pattern emerged during a speech task. In contrast to the hemodynamic responses within motor cortex and cerebellum, activation of the intrasylvian cortex turned out to be bound to overt task performance. These findings corroborate the assumption that the left insula supports the coordination of speech articulation. Similarly, the right insula might mediate temporo-spatial control of vocal tract musculature during overt singing. Both speech and melody production require the integration of sound structure or tonal patterns, respectively, with a speaker's emotions and attitudes. Considering the widespread interconnections with premotor cortex and limbic structures, the insula is especially suited for this task.

Neurofeedback of functional magnetic resonance imaging (fMRI) can be used to acquire selective control over activation in circumscribed brain areas, potentially inducing behavioral changes, depending on the functional role of the targeted cortical sites. In the present study, we used fMRI-neurofeedback to train subjects to enhance regional activation in the right inferior frontal gyrus (IFG) to influence speech processing and to modulate language-related performance. Seven subjects underwent real-time fMRI-neurofeedback training and succeeded in achieving voluntary regulation of their right Brodmann's area (BA) 45. To examine short-term behavioral impact, two linguistic tasks were carried out immediately before and after the training. A significant improvement of accuracy was observed for the identification of emotional prosodic intonations but not for syntactic processing. This evidence supports a role for the right IFG in the processing of emotional information and evaluation of affective salience. The present study confirms the efficacy of fMRI-biofeedback for noninvasive self-regulation of circumscribed brain activity.

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