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In the present study, we identified the most probable trajectories of point-to-point segregated connections between functional attentional centers using a combination of functional magnetic resonance imaging and a novel diffusion tensor imaging-based algorithm for pathway extraction. Cortical regions activated by a visuospatial attention task were(More)
Although the Tower of London (TOL) has been extensively used to assess planning ability in patients with Parkinson's disease (PD), the reported presence or extent of any planning deficits has been inconsistent. This may partly be due to the heterogeneity of the TOL tasks used and a failure to consider how structural problem parameters may affect task(More)
Apraxia is a cognitive disorder of skilled movements that characteristically affects the ability to imitate meaningless gestures, or to pantomime the use of tools. Despite substantial research, the neural underpinnings of imitation and pantomime have remained debated. An influential model states that higher motor functions are supported by different(More)
Despite the large number of behavioral and functional neuroimaging studies employing the Tower of London (ToL), the task's structural parameters and particularly their impact on planning have not been addressed so far. In this paper, we highlight the structural properties of ToL problems and provide evidence for their systematic and substantial effects on(More)
It is well established that the mid-dorsolateral prefrontal cortex (dlPFC) plays a critical role in planning. Neuroimaging studies have yielded predominantly bilateral dlPFC activations, but the existence and nature of functionally specific contributions of left and right dlPFC have remained elusive. In recent experiments, 2 independent parameters have been(More)
The Tower of London (ToL) test is widely used for measuring planning and aspects of problem solving. The primary focus of this study was to asses the relationship among different measures on the ToL. A secondary purpose was to examine the putative relationship between intelligence and working memory with that of ToL performance. Analyses of the(More)
Most neuroimaging studies on planning report bilateral activations of the dorsolateral prefrontal cortex (dlPFC). Recently, these concurrent activations of left and right dlPFC have been shown to double dissociate with different cognitive demands imposed by the planning task: Higher demands on the extraction of task-relevant information led to stronger(More)
BACKGROUND By mapping the dynamics of brain reorganization, functional magnetic resonance imaging MRI (fMRI) has allowed for significant progress in understanding cerebral plasticity phenomena after a stroke. However, cerebro-vascular diseases can affect blood oxygen level dependent (BOLD) signal. Cerebral autoregulation is a primary function of cerebral(More)
The neural mechanisms underlying spatial neglect are still disputed. Abnormal left parietal hyperactivation is proposed to lead to the rightward attentional bias, a clinical hallmark of neglect. Extinction, another deficit of visuospatial attention, is regarded as either a 'mild' form of neglect or a distinct syndrome. Although both neglect and extinction(More)
The current concept of a dual loop system of brain organization predicts a domain-general dual-pathway architecture involving dorsal and ventral fiber connections. We investigated if a similar dichotomy of brain network organization applies for pantomime (P) and imitation of meaningless gestures (I). Impairments of these tasks occur after left hemispheric(More)