Neuroimagery findings have shown similar cerebral networks associated with imagination and execution of a movement. On the other hand, neuropsychological studies of parietal-lesioned patients suggest that these networks may be at least partly distinct. In the present study, normal subjects were asked to either imagine or execute auditory-cued hand movements. Compared with rest, imagination and execution showed overlapping networks, including bilateral premotor and parietal areas, basal ganglia and cerebellum. However, direct comparison between the two experimental conditions showed that specific cortico-subcortical areas were more engaged in mental simulation, including bilateral premotor, prefrontal, supplementary motor and left posterior parietal areas, and the caudate nuclei. These results suggest that a specific neuronal substrate is involved in the processing of hand motor representations.
The present study aimed at determining the three-dimensional organization of striatal activation during foot, hand, face and eye movements. Seven right-handed, healthy volunteers were studied at 1.5 T using blood oxygen level dependent (BOLD) contrast. The tasks consisted of self-paced flexion/extension of the right and left fingers and right toes, contraction of the lips and saccadic eye movements. For foot, hand and face movements, striatal activation was mainly found in the putamen with a somatotopical organization, the foot area being dorsal, the face area more ventral and medial, the hand area in between. Overlap between somatotopic territories was present, more prominent for hand-face than for foot-face or foot-hand areas. In the putamen, the activated areas of the ipsi- and contralateral hand areas were not identical, suggesting a partial segregation of the ipsi- and contralateral striatal sensorimotor projections. For saccadic eye movements, bilateral activation was observed at the junction between the body and the head of the caudate nucleus and in the right putamen. These data present evidence for a somatotopic organization of the human striatum which corresponds with the topography of corticostriatal projections described in the non-human primates.
This article represents the update of ‘European Stroke Initiative Recommendations for Stroke Management’, first published in this Journal in 2000. The recommendations are endorsed by the 3 European societies which are represented in the European Stroke Initiative: the European Stroke Council, the European Neurological Society and the European Federation of Neurological Societies.
In dystonia there may be a dedifferentiation of the normally segregated cortico-subcortical sensorimotor maps in the putamen, which may contribute to the loss of functional selectivity of muscle activity observed in these dystonic subjects.
The direction in which the fundus projects was chosen as the morphological criterion between endovascular and surgical methods. The authors propose that microsurgical clip application should be the preferred option in the treatment of ACoA aneurysms with anteriorly directed fundi and that endovascular packing be selected for those lesions with posteriorly directed fundi, depending on morphological criteria.
A microsubthalamotomy (mSTN) effect is commonly described after implantation that improves Parkinson's motor disability and is considered to be an obvious sign of good placement of the definitive electrode within the subthalamic nucleus (STN). There has been no formal study, however, demonstrating whether this mSTN effect can predict the long-term efficacy of STN stimulation in Parkinson Disease. The mSTN effect was defined by the percentage improvement of unified parkinson's disease rating scale (UPDRS III) baseline score assessed the third day morning following STN implantation, after at least a 12 hour withdrawal of dopaminergic treatment and before the programmable pulse generator was switched on. It was assessed in 30 consecutive patients with PD submitted for STN stimulation. Multiple stepwise regression analysis showed that mSTN effect (P = 0.005) and global mean intensity of stimulation (P = 0.004) were accurate independent predictors of the 6-month postoperative UPDRS III motor score improvement in the off-drug/on-stimulation condition.
Object
For anterior communicating artery (ACoA) aneurysms, endovascular coil embolization constitutes a safe alternative therapeutic procedure to microsurgical clip occlusion. The authors' aim in this study was to evaluate the quality of life (QOL), cognitive function, and brain structure damage after the treatment of ruptured ACoA aneurysms in a group of patients who underwent microsurgical clipping (36 patients) compared with a reference group who underwent endovascular coiling (14 patients).
Methods
At 14 months posttreatment all patients underwent evaluations by independent observers. These observers evaluated global efficacy, executive functions using a frontal assessment battery of tests (Trail making test, Stroop tasks, dual task of Baddeley, verbal fluency, and Wisconsin Card Sorting test), behavior dysexecutive syndrome (the Inventaire du Syndrome Dysexécutif Comportemental questionnaire [ISDC]), and QOL by using the Reintegration To Normal Living Index. Brain damage was analyzed using MR imaging.
Results
In the microsurgical clipping and endovascular coiling groups, the distribution on the modified Rankin Scale (p = 0.19) and mean QOL score (85.4 vs 83.4, respectively) were similar. Moreover, the proportion of executive dysfunctions (19.4 vs 28.6%, respectively) and the mean score on the ISDC questionnaire (8.9 vs 8.5, respectively) were not significant, but verbal memory was more altered in the microsurgical clipping group (p = 0.055). Magnetic resonance imaging revealed that the incidence of local encephalomalacia and the median number of lesions per patient increased significantly in the microsurgical clipping group (p = 0.003).
Conclusions
In the 2 groups, no significant difference was observed regarding QOL, executive functions, and behavior. Despite the significant decrease in verbal memory after microsurgical clipping, the interdisciplinary approach remains a safe and useful strategy.
The emergence of high-resolution rapid imaging methods has enabled magnetic resonance (MR) imagers to noninvasively image the fine internal structure of cervical arterial walls. In this article, a comprehensive guide to performing high-resolution MR imaging of cervical arteries is provided, including the choice of coils, sequences, and imaging parameters, as well as tips for optimal image quality. Explanations and illustrations are given of using high-resolution MR imaging to quantify plaque volume, determine atherosclerotic plaque burden, depict plaque composition, and ultimately identify unstable plaque before it leads to a clinical event. Finally, the role of high-resolution MR imaging in the diagnosis of cervical dissection and inflammatory disease of the arterial wall is emphasized.
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