The Experts below are selected from a list of 81678 Experts worldwide ranked by ideXlab platform
Anders Gade - One of the best experts on this subject based on the ideXlab platform.
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putative tests of frontal lobe function a pet study of brain activation during stroop s test and verbal fluency
Journal of Clinical and Experimental Neuropsychology, 2002Co-Authors: Barbara Ravnkilde, Poul Videbech, Raben Rosenberg, Albert Gjedde, Anders GadeAbstract:Stroop's test and the Verbal Fluency test are commonly argued to be measures of the integrity of the prefrontal cortex. This assumption has only to some degree been confirmed by Lesion Studies. In the present study, Positron Emission Tomography (PET) with H 2 15 O was used to further validate Stroop's test and the Verbal Fluency as measures of frontal lobe function; both tests were implemented as activation paradigms during scanning of normal middleaged individuals. Stroop interference was found to activate the left anterior cingulate cortex, the supplementary motor cortex, thalamus, and the cerebellum. Although the prominent anterior cingulate activation is in the frontal lobe, it is not prefrontal. Verbal Fluency activated the left inferior frontal cortex and the left dorsolateral prefrontal cortex, the supplementary motor cortex, the anterior cingulate cortex and the cerebellum. These results bring this latter test closer to being a specific test of prefrontal function.
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putative tests of frontal lobe function a pet study of brain activation during stroop s test and verbal fluency
Journal of Clinical and Experimental Neuropsychology, 2002Co-Authors: Barbara Ravnkilde, Poul Videbech, Raben Rosenberg, Albert Gjedde, Anders GadeAbstract:Stroop's test and the Verbal Fluency test are commonly argued to be measures of the integrity of the prefrontal cortex. This assumption has only to some degree been confirmed by Lesion Studies. In the present study, Positron Emission Tomography (PET) with H 2 15 O was used to further validate Stroop's test and the Verbal Fluency as measures of frontal lobe function; both tests were implemented as activation paradigms during scanning of normal middleaged individuals. Stroop interference was found to activate the left anterior cingulate cortex, the supplementary motor cortex, thalamus, and the cerebellum. Although the prominent anterior cingulate activation is in the frontal lobe, it is not prefrontal. Verbal Fluency activated the left inferior frontal cortex and the left dorsolateral prefrontal cortex, the supplementary motor cortex, the anterior cingulate cortex and the cerebellum. These results bring this latter test closer to being a specific test of prefrontal function.
Juan Zhou - One of the best experts on this subject based on the ideXlab platform.
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dominant hemisphere lateralization of cortical parasympathetic control as revealed by frontotemporal dementia
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Christine C Guo, Virginia E Sturm, Juan Zhou, Efstathios D Gennatas, Andrew Trujillo, Alice Y Hua, Richard K CrawfordAbstract:The brain continuously influences and perceives the physiological condition of the body. Related cortical representations have been proposed to shape emotional experience and guide behavior. Although previous Studies have identified brain regions recruited during autonomic processing, neurological Lesion Studies have yet to delineate the regions critical for maintaining autonomic outflow. Even greater controversy surrounds hemispheric lateralization along the parasympathetic-sympathetic axis. The behavioral variant of frontotemporal dementia (bvFTD), featuring progressive and often asymmetric degeneration that includes the frontoinsular and cingulate cortices, provides a unique Lesion model for elucidating brain structures that control autonomic tone. Here, we show that bvFTD is associated with reduced baseline cardiac vagal tone and that this reduction correlates with left-lateralized functional and structural frontoinsular and cingulate cortex deficits and with reduced agreeableness. Our results suggest that networked brain regions in the dominant hemisphere are critical for maintaining an adaptive level of baseline parasympathetic outflow.
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dominant hemisphere lateralization of cortical parasympathetic control as revealed by frontotemporal dementia
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Virginia E Sturm, Juan Zhou, Efstathios D Gennatas, Andrew Trujillo, Richard K Crawford, Lara Stables, Joel H Kramer, Katherine P RankinAbstract:The brain continuously influences and perceives the physiological condition of the body. Related cortical representations have been proposed to shape emotional experience and guide behavior. Although previous Studies have identified brain regions recruited during autonomic processing, neurological Lesion Studies have yet to delineate the regions critical for maintaining autonomic outflow. Even greater controversy surrounds hemispheric lateralization along the parasympathetic–sympathetic axis. The behavioral variant of frontotemporal dementia (bvFTD), featuring progressive and often asymmetric degeneration that includes the frontoinsular and cingulate cortices, provides a unique Lesion model for elucidating brain structures that control autonomic tone. Here, we show that bvFTD is associated with reduced baseline cardiac vagal tone and that this reduction correlates with left-lateralized functional and structural frontoinsular and cingulate cortex deficits and with reduced agreeableness. Our results suggest that networked brain regions in the dominant hemisphere are critical for maintaining an adaptive level of baseline parasympathetic outflow.
Efstathios D Gennatas - One of the best experts on this subject based on the ideXlab platform.
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dominant hemisphere lateralization of cortical parasympathetic control as revealed by frontotemporal dementia
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Christine C Guo, Virginia E Sturm, Juan Zhou, Efstathios D Gennatas, Andrew Trujillo, Alice Y Hua, Richard K CrawfordAbstract:The brain continuously influences and perceives the physiological condition of the body. Related cortical representations have been proposed to shape emotional experience and guide behavior. Although previous Studies have identified brain regions recruited during autonomic processing, neurological Lesion Studies have yet to delineate the regions critical for maintaining autonomic outflow. Even greater controversy surrounds hemispheric lateralization along the parasympathetic-sympathetic axis. The behavioral variant of frontotemporal dementia (bvFTD), featuring progressive and often asymmetric degeneration that includes the frontoinsular and cingulate cortices, provides a unique Lesion model for elucidating brain structures that control autonomic tone. Here, we show that bvFTD is associated with reduced baseline cardiac vagal tone and that this reduction correlates with left-lateralized functional and structural frontoinsular and cingulate cortex deficits and with reduced agreeableness. Our results suggest that networked brain regions in the dominant hemisphere are critical for maintaining an adaptive level of baseline parasympathetic outflow.
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dominant hemisphere lateralization of cortical parasympathetic control as revealed by frontotemporal dementia
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Virginia E Sturm, Juan Zhou, Efstathios D Gennatas, Andrew Trujillo, Richard K Crawford, Lara Stables, Joel H Kramer, Katherine P RankinAbstract:The brain continuously influences and perceives the physiological condition of the body. Related cortical representations have been proposed to shape emotional experience and guide behavior. Although previous Studies have identified brain regions recruited during autonomic processing, neurological Lesion Studies have yet to delineate the regions critical for maintaining autonomic outflow. Even greater controversy surrounds hemispheric lateralization along the parasympathetic–sympathetic axis. The behavioral variant of frontotemporal dementia (bvFTD), featuring progressive and often asymmetric degeneration that includes the frontoinsular and cingulate cortices, provides a unique Lesion model for elucidating brain structures that control autonomic tone. Here, we show that bvFTD is associated with reduced baseline cardiac vagal tone and that this reduction correlates with left-lateralized functional and structural frontoinsular and cingulate cortex deficits and with reduced agreeableness. Our results suggest that networked brain regions in the dominant hemisphere are critical for maintaining an adaptive level of baseline parasympathetic outflow.
John D E Gabrieli - One of the best experts on this subject based on the ideXlab platform.
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cognitive processing speed and the structure of white matter pathways convergent evidence from normal variation and Lesion Studies
NeuroImage, 2008Co-Authors: And U Turken, Susan Whitfieldgabrieli, Roland Bammer, Juliana V Baldo, Nina F Dronkers, John D E GabrieliAbstract:We investigated the relation between cognitive processing speed and structural properties of white matter pathways via convergent imaging Studies in healthy and brain-injured groups. Voxel-based morphometry (VBM) was applied to diffusion tensor imaging data from thirty-nine young healthy subjects in order to investigate the relation between processing speed, as assessed with the Digit-Symbol subtest from WAIS-III, and fractional anisotropy, an index of microstructural organization of white matter. Digit-Symbol performance was positively correlated with fractional anisotropy of white matter in the parietal and temporal lobes bilaterally and in the left middle frontal gyrus. Fiber tractography indicated that these regions are consistent with the trajectories of the superior and inferior longitudinal fasciculi. In a second investigation, we assessed the effect of white matter damage on processing speed using voxel-based Lesion-symptom mapping (VLSM) analysis of data from seventy-two patients with left-hemisphere strokes. Lesions in left parietal white matter, together with cortical Lesions in supramarginal and angular gyri were associated with impaired performance. These findings suggest that cognitive processing speed, as assessed by the Digit-Symbol test, is closely related to the structural integrity of white matter tracts associated with parietal and temporal cortices and left middle frontal gyrus. Further, fiber tractography applied to VBM results and the patient findings suggest that the superior longitudinal fasciculus, a major tract subserving fronto-parietal integration, makes a prominent contribution to processing speed.
R T Knight - One of the best experts on this subject based on the ideXlab platform.
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the functional neuroanatomy of working memory contributions of human brain Lesion Studies
Neuroscience, 2006Co-Authors: N G Muller, R T KnightAbstract:Abstract Studies of patients with focal brain Lesions remain critical components of research programs attempting to understand human brain function. Whereas functional imaging typically reveals activity in distributed brain regions that are involved in a task, Lesion Studies can define which of these brain regions are necessary for a cognitive process. Further, Lesion Studies are less critical regarding the selection of baseline conditions needed in functional brain imaging research. Lesion Studies suggest a functional subdivision of the visuospatial sketchpad of working memory with a ventral stream reaching from occipital to temporal cortex supporting object recognition and a dorsal stream connecting the occipital with parietal cortex enabling spatial operations. The phonological loop can be divided into a phonological short-term store in inferior parietal cortex and an articulatory subvocal rehearsal process relying on brain areas necessary for speech production, i.e. Broca’s area, the supplementary motor association area and possibly the cerebellum. More uncertainty exists regarding the role of the prefrontal cortex in working memory. Whereas single cell Studies in non-human primates and functional imaging Studies in humans have suggested an extension of the ventral and dorsal path into different subregions of the prefrontal cortex, Lesion Studies together with recent single-cell and imaging Studies point to a non-mnemonic role of the prefrontal cortex, including attentional control of sensory processing, integration of information from different domains, stimulus selection and monitoring of information held in memory. Our own data argue against a modulatory view of the prefrontal cortex and suggest that processes supporting working memory are distributed along ventral and dorsal lateral prefrontal cortex.