Cortical plasticity associated with stuttering therapy.

Abstract Neuroimaging studies have indicated that persistent developmental stuttering (PDS) may be associated both with an abnormality in white matter of left-hemispheric speech areas and a right-hemispheric hyperactivity. The latter may compensate for the deficient structural connectivity in the left hemisphere. To investigate the effects of stuttering therapy on brain activity nine male adults with PDS underwent functional magnetic resonance imaging (fMRI) before and within 12 weeks after fluency shaping therapy. Brain response differences during overt sentence reading before and after therapy were assessed by utilizing random effects analyses. After therapy, a more widespread activation was observed in frontal speech and language regions and temporal areas of both hemispheres, particularly and more pronounced on the left side. Interestingly, distinct posttreatment left-sided activation increases were located directly adjacent to a recently detected area of white matter anomaly [M. Sommer, M.A. Koch, W. Paulus, C. Weiller, C. Büchel (2002 Neumann et al. / Journal of Fluency Disorders 30 (2005) [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] execution, and temporal areas. Hence, a therapeutic mechanism can be assumed to remodel brain circuitry close to the source of the dysfunction instead of reinforcing compensation via homologous contralateral brain networks. Educational objectives: The reader will learn about and be able to: (1) describe brain activation changes detected shortly after fluency-shaping therapy; (2) identify left-hemispheric regions where a (re)functionalization after fluency-shaping therapy seems to occur adjacent to a recently described abnormal white matter region in PDS subjects; and (3) discuss how an effective cerebral compensation mechanism for stuttering could work

tert-Butoxy­triphenyl­silane

The title compound, C22H24OSi or Ph3SiOtBu, shows a distorted tetra­hedral coordination sphere around the Si atom. The C—O—Si angle is 135.97 (12)° and the O—Si distance is 1.6244 (13) Å. The mol­ecules are held together by weak inter­actions only. An H⋯H distance of 2.2924 (7) Å is found between aryl H atoms and is the shortest inter­molecular distance in the structure. With regard to the broad applicability of R 3SiO structural motifs in all fields of chemistry, the mol­ecule demonstrates a common model system for silicon centers surrounded by sterically demanding substituents

Comparison of Accurate Dot Product Algorithms

A recently proposed algorithm for the accurate computation of the dot product [Kob 94] has been implemented and modified in order to obtain the best possible algorithm for the Aquarels toolbox. It is compared with the other well known algorithms with respect to runtime and intermediate storage space. A considerable improvement of the performance is obtained by a combination of this algorithm with an old one

An Optimality Criterion for Arithmetic of Complex Sets

Uncertainty of measuring complex-valued physical quantities can be described by complex sets. These sets can have complicated shapes, so we would like to find a good approximating family of sets. Which approximating family is the best? We reduce the corresponding optimization problem to a geometric one: namely, we prove that, under some reasonable conditions, an optimal family must be shift-, rotation- and scale-invariant. We then use this geometric reduction to conclude that the best approximating low-dimensional families consist of sets with linear or circular boundaries. This result is consistent with the fact that such sets have indeed been successful in computations