Detection of acute brainstem infarction by using DWI/MRI.

Even using diffusion-weighted images (DWI) detection of acute brainstem infarction (BI) is still a challenge. To evaluate the clinical efficacy of a DWI protocol with improved spatial resolution all images of 44 patients with clinically possible BI on admission (24 patients with definite BI and 20 patients with other etiologies) and first DWI within 24 h after symptom onset were blindly reanalyzed for visibility and detection of BI on the first DWI by reviewers with different expertise levels. Neuroradiologists identified definite BI in 21 out of 24 patients (sensitivity 90%, specificity 100%); neurologists and junior house officers achieved similar results (sensitivity 86 and 83%, specificity 98 and 97%). The use of DWI allows a definite diagnosis of BI, even if raters have limited experience.

Reduced recruitment of motor association areas during bimanual coordination in concert pianists.

Bimanual motor coordination is essential for piano playing. The functional neuronal substrate for high-level bimanual performance achieved by professional pianists is unclear. We compared professional pianists to musically naïve controls while carrying out in-phase (mirror) and anti-phase (parallel) bimanual sequential finger movements during functional magnetic resonance imaging (fMRI). This task corresponds to bimanually playing scales practiced daily by pianists from the beginning of piano playing. Musicians and controls showed significantly different functional activation patterns. When comparing performance of parallel movements to rest, musically naïve controls showed stronger activations than did pianists within a network including anterior cingulate cortex, right dorsal premotor cortex, both cerebellar hemispheres, and right basal ganglia. The direct comparison of bimanual parallel to mirror movements between both groups revealed stronger signal increases in controls within mesial premotor cortex (SMA), bilateral cerebellar hemispheres and vermis, bilateral prefrontal cortex, left ventral premotor cortex, right anterior insula, and right basal ganglia. These findings suggest increased efficiency of cortical and subcortical systems for bimanual movement control in musicians. This may be fundamental to achieve high-level motor skills allowing the musician to focus on artistic aspects of musical performance.

The role of lateral premotor-cerebellar-parietal circuits in motor sequence control: a parametric fMRI study.

Functional characterisation of higher order motor systems can be obtained by modulating the processing demands imposed onto relevant motor circuitries. Here we performed whole-brain functional magnetic resonance imaging (fMRI) and parametric statistical analyses in eight healthy volunteers to study task-related recruitment of motor circuits associated with unilateral finger movement sequences of increasing length and complexity, but with equal basic motor parameters. Statistical parametric mapping software was applied for analysis. Categorical analysis of the main effect of motor action showed cerebral activation in the established cortical and subcortical motor network. Parametric analyses of the blood-oxygen-level-dependent (BOLD) contrast revealed significant signal increases correlating to sequence length and complexity in a subset of activated areas, notably contralateral ventral and dorsal premotor cortex, bilateral superior parietal cortex, left inferior frontal gyrus/Broca's area, right dentate nucleus, and left visual association cortex. These data underscore the importance of ventral premotor-cerebellar-parietal circuits in processing length and complexity of sequential finger movements.