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A study of cognition emerging from a neurobiological perspective, as opposed to one emerging from a purely computational or psychological perspective, begins with observations of the human brain in normal and pathological states and is furthered by the investigation of hypotheses which are articulated using neuroanatomical nomenclature. Brainvox is an(More)
When the landmark patient Phineas Gage died in 1861, no autopsy was performed, but his skull was later recovered. The brain lesion that caused the profound personality changes for which his case became famous has been presumed to have involved the left frontal region, but questions have been raised about the involvement of other regions and about the exact(More)
We describe a multistep technique for three-dimensional reconstruction and analysis of brain lesions in vivo, based on the manipulation of magnetic resonance raw data obtained with a special protocol. The technique permits the direct visual identification of neuroanatomical landmarks in each brain specimen and eliminates the need to rely on averaged(More)
We describe and evaluate a practical, automated algorithm based on local statistical mixture modeling for segmenting single-channel, T1-weighted volumetric magnetic resonance images of the brain into gray matter, white matter, and cerebrospinal fluid. We employed a stereological sampling method to assess, prospectively, the performance of the method with(More)
Category-related effects in the retrieval of conceptual and lexical knowledge for concrete entities have been well documented in lesion studies, and also with functional imaging and electrophysiological approaches. For example, brain-damaged subjects may be impaired in the ability to recognize or to name animals but not tools, or the opposite pattern may(More)
Scenarios regarding the evolution of cognitive function in hominids depend largely on our understanding of the organization of the frontal lobes in extant humans and apes. The frontal lobe is involved in functions such as creative thinking, planning of future actions, decision making, artistic expression, aspects of emotional behavior, as well as working(More)
Four pixel-based methods for estimating regional activation in positron emission tomography (PET) images were implemented so as to allow the comparison of their performances in the same dataset. Change distribution analysis, Worsley's method, a pixelwise general linear model, a nonparametric method, and several methods derived from them were investigated.(More)
In this paper we introduce a new indexing scheme for progressive traversal and visualization of large regular grids. We demonstrate the potential of our approach by providing a tool that displays at interactive rates planar slices of scalar field data with very modest computing resources. We obtain unprecedented results both in terms of absolute performance(More)
Real-time parametric statistical analysis of functional MRI (fMRI) data would potentially enlarge the scope of experimentation and facilitate its application to clinical populations. A system is described that addresses the need for rapid analysis of fMRI data and lays the foundation for dealing with problems that impede the application of fMRI to clinical(More)
Increases in the number and size of volumetric meshes have popularized the use of hierarchical multi-resolution representations for visualization. A key component of these schemes has become the adaptive traversal of hierarchical data-structures to build, in real time, approximate representations of the input geometry for rendering. For very large datasets(More)