Multimodal neuroimaging in patients with disorders of consciousness showing "functional hemispherectomy".

Beside behavioral assessment of patients with disorders of consciousness, neuroimaging modalities may offer objective paraclinical markers important for diagnosis and prognosis. They provide information on the structural location and extent of brain lesions (e.g., morphometric MRI and diffusion tensor imaging (DTI-MRI) assessing structural connectivity) but also their functional impact (e.g., metabolic FDG-PET, hemodynamic fMRI, and EEG measurements obtained in "resting state" conditions). We here illustrate the role of multimodal imaging in severe brain injury, presenting a patient in unresponsive wakefulness syndrome (UWS; i.e., vegetative state, VS) and in a "fluctuating" minimally conscious state (MCS). In both cases, resting state FDG-PET, fMRI, and EEG showed a functionally preserved right hemisphere, while DTI showed underlying differences in structural connectivity highlighting the complementarities of these neuroimaging methods in the study of disorders of consciousness.Peer reviewe

Cortical communication and the comparison of colors

The hues or the colorimetric purities of a pair of colored targets can be compared with similar precision whether the targets are juxtaposed or fall at well-separated positions in the visual field. This is the case even if the stimuli are 10° apart and fall in opposite hemifields. What could be the neural processes that underlie such comparisons? We are led to ask whether the long-range, white-matter tracts of the brain constitute a neural net (where representations are embodied in the weightings and signs of connections between the nodes of the net) or a communication network (where the same physical substrate carries different information from moment to moment).Supported by BBSRC (BB/S000623/1) and Wellcome Trust (082378/Z/07/Z)

Zifazah: A Scientific Visualization Language for Tensor Field Visualizations

This thesis presents the design and prototype implementation of a scientific visualization language called Zifazah for composing and exploring 3D visualizations of diffusion tensor magnetic resonance imaging (DT-MRI or DTI) data. Unlike existing tools allowing flexible customization of data visualizations that are programmer-oriented, Zifazah focuses on domain scientists as end users in order to enable them to freely compose visualizations of their scientific data set. Verbal descriptions of end users about how they would build and explore DTI visualizations are analyzed to collect syntax, semantics, and control structures of the language. Zifazah makes use of the initial set of lexical terms and semantical patterns to provide a declarative language in the spirit of intuitive syntax and usage. Along with sample scripts representative of the main language design features, some new DTI visualizations created by end users using the novel language have also been presented

Effects of bipolar disorder on intrinsic brain networks

Introduction: Bipolar disorder (BD) is a brain network disorder that affects cognitive and emotional functioning, and is associated with prefrontal and/or limbic dysfunction. Functional Magnetic Resonance Imaging (fMRI) allows identification of intrinsic brain networks (IBN), like the default mode network (DMN) and executive control network (ECN), which are consistent with previously established functional and anatomical relationships within the brain. Analysing the functional connectivity (integrity, extent and inter-relationships) of these networks, allows a deeper understanding of brain function in health and disease. In BD, there are functional connectivity changes in the DMN, ECN and cerebellar network (CERN). We evaluate IBN in BD, to explore changes in the functional connectivity between the cerebellum, fronto-cortical and paralimbic regions. Methods: Data from 14 BD subjects and 10 control subjects was analysed after fMRI. Changes were evaluated in 3 IBN (DMN, ECN and CERN) using an FMRIB Software Library (FSL) pipeline: MELODIC/ICA-AROMA, dual-regression, randomise and Local False Discovery Rate (FDR) to identify changes in functional connectivity bipolar subjects compared to controls. Results: Subjects with BD showed decreased connectivity between the CERN and a cluster in the right precuneus; and between the ECN and a cluster in the left OFC. There was also increased connectivity between the ECN and a cluster in the left temporal pole. No connectivity changes involving the DMN were identified. Voxels within the clusters were significant at p < 0.05 with local FDR. Peaks within the clusters remained significant after further Bonferroni correction for multiple comparisons (p < 0.017). Conclusion: The finding of altered functional connectivity in BD, in networks and regions involved in cognitive/emotional processes, highlights its complex neurobiology, and suggests that abnormal connectivity may help to explain the clinical picture. These findings should be replicated with larger samples, but may represent a further advance in understanding the role of functional connectivity in the pathology of BD, and contribute to laying the foundation for functional neuroimaging as a diagnostic tool in psychiatry

What can autism teach us about the role of sensorimotor systems in higher cognition? New clues from studies on language, action semantics, and abstract emotional concept processing.

Within the neurocognitive literature there is much debate about the role of the motor system in language, social communication and conceptual processing. We suggest, here, that autism spectrum conditions (ASC) may afford an excellent test case for investigating and evaluating contemporary neurocognitive models, most notably a neurobiological theory of action perception integration where widely-distributed cell assemblies linking neurons in action and perceptual brain regions act as the building blocks of many higher cognitive functions. We review a literature of functional motor abnormalities in ASC, following this with discussion of their neural correlates and aberrancies in language development, explaining how these might arise with reference to the typical formation of cell assemblies linking action and perceptual brain regions. This model gives rise to clear hypotheses regarding language comprehension, and we highlight a recent set of studies reporting differences in brain activation and behaviour in the processing of action-related and abstract-emotional concepts in individuals with ASC. At the neuroanatomical level, we discuss structural differences in long-distance frontotemporal and frontoparietal connections in ASC, such as would compromise information transfer between sensory and motor regions. This neurobiological model of action perception integration may shed light on the cognitive and social-interactive symptoms of ASC itself, building on and extending earlier proposals linking autistic symptomatology to motor disorder and dysfunction in action perception integration. Further investigating the contribution of motor dysfunction to higher cognitive and social impairment, we suggest, is timely and promising as it may advance both neurocognitive theory and the development of new clinical interventions for this population and others characterised by early and pervasive motor disruption

New Foundation in the Sciences: Physics without sweeping infinities under the rug

It is widely known among the Frontiers of physics, that “sweeping under the rug” practice has been quite the norm rather than exception. In other words, the leading paradigms have strong tendency to be hailed as the only game in town. For example, renormalization group theory was hailed as cure in order to solve infinity problem in QED theory. For instance, a quote from Richard Feynman goes as follows: “What the three Nobel Prize winners did, in the words of Feynman, was to get rid of the infinities in the calculations. The infinities are still there, but now they can be skirted around . . . We have designed a method for sweeping them under the rug. [1] And Paul Dirac himself also wrote with similar tune: “Hence most physicists are very satisfied with the situation. They say: Quantum electrodynamics is a good theory, and we do not have to worry about it any more. I must say that I am very dissatisfied with the situation, because this so-called good theory does involve neglecting infinities which appear in its equations, neglecting them in an arbitrary way. This is just not sensible mathematics. Sensible mathematics involves neglecting a quantity when it turns out to be small—not neglecting it just because it is infinitely great and you do not want it!”[2] Similarly, dark matter and dark energy were elevated as plausible way to solve the crisis in prevalent Big Bang cosmology. That is why we choose a theme here: New Foundations in the Sciences, in order to emphasize the necessity to introduce a new set of approaches in the Sciences, be it Physics, Cosmology, Consciousness etc