Phasic modulation of corticomotor excitability during passive movement of the upper limb: effects of movement frequency and muscle specificity

Modulations in the excitability of spinal reflex pathways during passive rhythmic movements of the lower limb have been demonstrated by a number of previous studies [4]. Less emphasis has been placed on the role of supraspinal pathways during passive movement, and on tasks involving the upper limb. In the present study, transcranial magnetic stimulation (TMS) was delivered to subjects while undergoing passive flexion-extension movements of the contralateral wrist. Motor evoked potentials (MEPs) of flexor carpi radialis (FCR) and abductor pollicus brevis (APB) muscles were recorded. Stimuli were delivered in eight phases of the movement cycle during three different frequencies of movement. Evidence of marked modulations in pathway excitability was found in the MEP amplitudes of the FCR muscle, with responses inhibited and facilitated from static values in the extension and flexion phases, respectively. The results indicated that at higher frequencies of movement there was greater modulation in pathway excitability. Paired-pulse TMS (sub-threshold conditioning) at short interstimulus intervals revealed modulations in the extent of inhibition in MEP amplitude at high movement frequencies. In the APE muscle, there was some evidence of phasic modulations of response amplitude, although the effects were less marked than those observed in FCR. It is speculated that these modulatory effects are mediated via Ia afferent pathways and arise as a consequence of the induced forearm muscle shortening and lengthening. Although the level at which this input influences the corticomotoneuronal pathway is difficult to discern, a contribution from cortical regions is suggested. (C) 2001 Published by Elsevier Science B.V.

No Easy Way Through: Black Workers and Race Leadership at the Nadir

It is difficult, even excruciating, to imagine the staggering descent from high optimism to despondency experienced by many African Americans who lived between emancipation and the dawn of the twentieth century. For historians living in the post–civil rights era, recapturing the scale, velocity, and brutality of that dramatic fall has been hampered by two conceptual problems. The first of these, undergirded by prominent trends in the formerly “new” social history, is a widely shared enthusiasm for illuminating those hidden corners of daily life where men and women on the receiving end of Jim Crow continued to wield a degree of control. “Agency” has been the buzzword for a generation of scholarship that emphasizes the staying power and persistence of black Southerners in the face of relentless assaults on their social and economic status, their civil rights, and even, at times, their collective existence. This is, in many ways, an understandable reaction to an earlier consensus that relegated black historical initiative to the margins of a national fable cleansed of unseemly violence and sharp social conflict, but it can also be problematic.

Any Nearer to Victory in the Fifty Years War?:Assessing the European Commission’s Leadership, Weapons and Strategies towards combating Cartels

Some 50 years after its creation EU competition policy remains firmly entrenched as one of the most developed examples of supranational governance within the European Union. Although there has been a marked increase in interest among political scientists in competition policy in recent years there are still gaps in terms of overall coverage. One area that has been largely overlooked centres on cartels. Cartel policy has emerged as a highly salient issue and main priority of the Commission's competition policy since the late 1990s. Certainly, the recent restructuring of the EU cartel enforcement regime, the imposition of ever higher fines and a determined EU Competition Commissioner have fuelled growing media attention while new notices and regulations increasingly occupy the interests and minds of practitioners. The European Commission has constantly extended its activities on the competition policy front and its increasingly aggressive strategies to combat cartels provides political scientists with a fascinating case study of governance in action and illustrates the ways – such as leniency programmes, higher fines, enhanced and better equipped resources as well as internal reorganisation in which the European regulator is pursuing such conspiracies. This article traces the evolution and development of EU cartel policy since its inception and assesses the Commission's strategies and considers just to what extent the European Commission is winning its war against business cartelisation.