Damage to fronto-parietal networks impairs motor imagery ability after stroke : a voxel-based lesion symptom mapping study

Background: mental practice with motor imagery has been shown to promote motor skill acquisition in healthy subjects and patients. Although lesions of the common motor imagery and motor execution neural network are expected to impair motor imagery ability, functional equivalence appears to be at least partially preserved in stroke patients.Aim: to identify brain regions that are mandatory for preserved motor imagery ability after stroke.Method: thirty-seven patients with hemiplegia after a first time stroke participated. Motor imagery ability was measured using a Motor Imagery questionnaire and temporal congruence test. A voxelwise lesion symptom mapping approach was used to identify neural correlates of motor imagery in this cohort within the first year post-stroke.Results: poor motor imagery vividness was associated with lesions in the left putamen, left ventral premotor cortex and long association fibres linking parieto-occipital regions with the dorsolateral premotor and prefrontal areas. Poor temporal congruence was otherwise linked to lesions in the more rostrally located white matter of the superior corona radiata. Conclusion: This voxel-based lesion symptom mapping study confirms the association between white matter tract lesions and impaired motor imagery ability, thus emphasizing the importance of an intact fronto-parietal network for motor imagery. Our results further highlight the crucial role of the basal ganglia and premotor cortex when performing motor imagery tasks

A Brief History of Islamic Civilization from Its Genesis in the Late Nineteenth Century to Its Institutional Entrenchment

This article sketches the early history of Islamic civilization from its genesis in the late nineteenth century to its institutionalization in the twentieth. Key moments include its enshrinement in journals and a monumental encyclopedia and the flight of European Semitists to the United States. Its institutionalization in the undergraduate curriculum at the University of Chicago in 1956 created a successful model for the subsequent dissemination of Islamic civilization. Working in a committee on general education (the core curriculum) in the social sciences at the University of Chicago, Marshall Hodgson inaugurated Islamic civilization as a subject of university study that was not just for specialists but available to American college students as fulfilling a basic requirement in a liberal arts education. Many other universities followed this practice. Since then, Islamic civilization has come to be shared by the educated public. Today it is an internationally accepted and wellfunded entity that confers contested social power but still lacks analytical power.

Semantic Clone Detection via Probabilistic Software Modeling

Semantic clone detection is the process of finding program elements with similar or equal runtime behavior. For example, detecting the semantic equality between the recursive and iterative implementation of the factorial computation. Semantic clone detection is the de facto technical boundary of clone detectors. This boundary was tested over the last years with interesting new approaches. This work contributes a semantic clone detection approach that detects clones with 0% syntactic similarity. We present Semantic Clone Detection via Probabilistic Software Modeling (SCD-PSM) as a stable and precise solution to semantic clone detection. PSM builds a probabilistic model of a program that is capable of evaluating and generating runtime data. SCD-PSM leverages this model and its model elements to finding behaviorally equal model elements. This behavioral equality is then generalized to semantic equality of the original program elements. It uses the likelihood between model elements as a distance metric. Then, it employs the likelihood ratio significance test to decide whether this distance is significant, given a pre-specified and controllable false-positive rate. The output of SCD-PSM are pairs of program elements (i.e., methods), their distance, and a decision whether they are clones or not. SCD-PSM yields excellent results with a Matthews Correlation Coefficient greater 0.9. These results are obtained on classical semantic clone detection problems such as detecting recursive and iterative versions of an algorithm, but also on complex problems used in coding competitions.Comment: 12 pages, 2 pages of references, 5 listings, 2 figures, 4 table