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Abstract: Auditory feedback is important for the control of voice fundamental frequency (F0). In the present study we used neuroimaging to identify regions of the brain responsible for sensory control of the voice. We used a pitch-shift paradigm where subjects respond to an alteration, or shift, of voice pitch auditory feedback with a reflexive change in F0. To determine the neural substrates involved in these audio-vocal responses, subjects underwent fMRI scanning while vocalizing with or without pitch-shifted feedback. The comparison of shifted and unshifted vocalization revealed activation bilaterally in the superior temporal gyrus (STG) in response to the pitch shifted feedback. We hypothesize that the STG activity is related to error detection by auditory error cells located in the superior temporal cortex and efference copy mechanisms whereby this region is responsible for the coding of a mismatch between actual and predicted voice F0. [Copyright &y& Elsevier]

The intention to execute a movement can modulate our perception of sensory events; however, theoretical accounts of these effects, and also empirical data, are often contradictory. We investigated how perception of a somatosensory stimulus differed according to whether it was delivered to a limb being prepared for movement or to a nonmoving limb. Our results demonstrate that individuals perceive a somatosensory stimulus delivered to the “moving” limb as occurring significantly later than when an identical stimulus is delivered to a “nonmoving” limb. Furthermore, human brain imaging (fMRI) analyses demonstrate that this modulation is accompanied by a significant decrease in BOLD signal in the right parietal operculum (SII) for stimuli delivered to the moving limb. These results indicate that during movement preparation a network of premotor brain areas may facilitate movement execution by attenuating the processing of behaviorally irrelevant signals within higher-order secondary somatosensory (SII) areas. [ABSTRACT FROM PUBLISHER]

Abstract: Computational theories of motor control propose that the brain uses ‘forward’ models of the body to ensure accurate control of movements. Forward ‘dynamic’ models are thought to generate an estimate of the next motor state for an upcoming movement: thereby providing a dynamic representation of the current postural configuration of the body that can be utilised during movement planning and execution. We used event-related functional magnetic resonance imaging [fMRI] to investigate brain areas involved in maintaining and updating the postural representations of the upper limb that participate in the control of reaching movements. We demonstrate that the neural correlates for executing memory-guided reaching movements to unseen target locations that were defined by arm posture, are primarily within regions of the superior parietal lobule [SPL]: including an area of the medial SPL identified as the human homologue of the ‘parietal reach region’ [PRR]. Using effective connectivity analyses we show that signals that influence the BOLD response within this area originate within premotor areas of the frontal lobe, including premotor cortex and the supplementary motor area. These data are consistent with the view that the SPL maintains an up-to-date estimate of the current postural configuration of the arm that is used during the planning and execution of reaching movements. [ABSTRACT FROM AUTHOR]

Abstract: This work investigated human brain activity in healthy subjects during an involuntary movement. The involuntary movement was driven by an involuntary postural aftercontraction of the deltoid muscle of the shoulder which follows the cessation of a prolonged isometric voluntary contraction. Previous authors have suggested that this aftercontraction phenomenon does not involve the cerebral cortex. To test this idea we examined brain activation using functional magnetic resonance imaging (fMRI) during the involuntary movement and during a matched voluntary movement. In contrast to the conjectures of earlier authors, during the involuntary movement there was widespread activation of the cerebral cortex. There were also clear activation differences between conditions. The voluntary movement showed activation of the putamen whereas the involuntary movement showed much greater activation of the anterior cingulate cortex (BA 24/32). There were also some similarities in the brain areas activated under both movement conditions namely in the left hemisphere precentral gyrus (BA 4), the left hemisphere superior parietal lobe (BA 7), and the bilateral superior temporal gyrus (BA 22). Activity was also present in the caudate nucleus, the thalamus, and the cerebellum. The results are discussed in relation to theories of aftercontraction generation and error processing by the anterior cingulate. [Copyright &y& Elsevier]

Highlights: [•] We modeled voice networks with and without auditory shifts using structural equation modeling. [•] We examined differences in connectivity between the two models. [•] We determined that STG is critical to vocalization and error detection/correction. [ABSTRACT FROM AUTHOR]

Abstract: Tourette syndrome [TS] is a neurodevelopmental disorder characterised by chronic vocal and motor tics. TS has been associated with dysfunctional cognitive (inhibitory) control of behaviour, however the evidence for this, beyond the occurrence of tics, is scant. Furthermore, in recent studies of uncomplicated TS, it has been shown that adolescents with TS exhibit paradoxically enhanced cognitive control of motor output, consistent with the typical developmental profile of increasing control of tics during adolescence. Here we present arguments, together with new data, that run counter to the widely held view that prefrontal cortex (PFC) is the source of inhibitory task-control signals. Instead, we argue that PFC should be viewed as a source of facilitatory signals that bias competition in brain areas more directly involved in motor execution. Importantly, we argue that in TS, over-activation of PFC may contribute to the hyper-excitability of motor regions and the occurrence of tics; and that compensatory changes, leading to enhanced cognitive control in TS, may primarily be implemented by distributed changes in local cortical excitability. [Copyright &y& Elsevier]