The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform
Mark Hallett - One of the best experts on this subject based on the ideXlab platform.
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the functional neuroanatomy of simple and complex sequential finger movements a pet study
Brain, 1998Co-Authors: Maria Jose Catalan, Manabu Honda, R A Weeks, Leonardo G Cohen, Mark HallettAbstract:The brain regions activated by simple repetitive and sequential finger movements of different length were localized by measuring regional cerebral blood flow (rCBF) with PET. The experimental design consisted of finger movements cued by auditory pacing at 0.5 Hz. In all conditions of different sequence length the contralateral primary sensorimotor and premotor cortex, supplementary motor Area and ipsilateral cerebellar cortex were activated. These Areas showed a large increase in activation from rest to simple repetitive movement, and a further increase with the shortest sequence, suggesting an executive role in running sequences. The ipsilateral premotor Area (Brodmann Area 6), bilateral posterior parietal Areas (Brodmann Area 7) and precuneus showed an increase in rCBF related only to the length of the sequences, without any change from rest to simple repetitive movement. These Areas are more selectively related to sequence performance. This finding is consistent with the hypothesis that these Areas function in the storage of motor sequences in spatial working memory. Our results suggest that sequential finger movements recruit discrete sets of brain Areas with different functions.
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Complexity affects regional cerebral blood flow change during sequential finger movements
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1996Co-Authors: Norihiro Sadato, Gregory Campbell, Vicente Ibáñez, M.-p. Deiber, Mark HallettAbstract:Brain regions activated with complex sequential finger movements were localized by measuring regional cerebral blood flow (rCBF) with positron emission tomography. Whereas the total number and frequency of finger movements were kept constant, the complexity of auditory cued sequential finger movements of the right hand varied, with sequence length as the independent variable. In four conditions of differing complexity, the bilateral primary sensorimotor Area, left ventral premotor cortex, posterior supplementary motor Area, right superior part of the cerebellum, and left putamen were consistently and equally activated. This finding suggests an executive role in running sequences, regardless of their length. The right dorsal premotor cortex (Brodmann Area 6) and the right precuneus (Brodmann Area 7) showed a linear increase of rCBF as sequence complexity increased. This finding is consistent with the hypothesis that these Areas function in the storage of motor sequences in spatial working memory and the production of ongoing sequential movement with reference to that of buffered memory. A similar increase in the cerebellar vermis and the left thalamus likewise suggests a role of these subcortical structures in complexity of sequential finger movements. Conversely, the left inferior parietal lobule showed a decrease of rCBF as complexity increased. Because short-term phonological storage is localized to this Area, we suggest that the visuospatial working memory system may suppress other systems not in use. Our findings suggest that complex sequential finger movements recruit a discrete set of brain Areas, in addition to Areas underlying the execution of simple movement sequences.
Sung Ho Jang - One of the best experts on this subject based on the ideXlab platform.
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Anatomical location of transcallosal sensorimotor fibers in the human brain: Diffusion tensor tractography study
Translational Neuroscience, 2013Co-Authors: Jung Pyo Seo, Sung Ho JangAbstract:Many diffusion tensor tractography (DTT) studies have reported on the topography of transcallosal fibers (TCF). However, little detailed anatomical information on TCF that can be easily applied for clinical purposes is known. Using probabilistic DTT, we attempted to determine the anatomical location of the TCF for motor and sensory function in the human brain. A total of 51 healthy subjects were recruited for this study. Diffusion tensor images (DTIs) were obtained at 1.5 T, and four TCF for the premotor cortex (PMC), the primary motor cortex (M1) for hand and leg, and the primary somatosensory cortex (S1) were obtained using FMRIB software. Locations of the TCF were defined as the highest probabilistic location on the midsagittal slice of the corpus callosum. We measured distances between the most anterior and posterior points of the corpus callosum. The relative mean distances of the highest probabilistic location for the precentral knob PMC (Brodmann Area 6 anterior to the precentral knob), hand M1, leg M1, and precentral knob S1 (postcentral gyrus posterior to the precentral knob) TCF were 48.99%, 59.78%, 67.93%, and 73,48% from the most anterior point of the CC, respectively. According to our findings, the precentral knob PMC, hand M1, leg M1, and precentral knob S1 TCF were located at the anterior body, posterior body, posterior body, and isthmus according to Witelson’s classification, respectively.
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ANATOMICAL LOCATION OF TRANSCALLOSAL SENSORIMOTOR FIBERS IN THE HUMAN BRAIN: DIFFUSION
2013Co-Authors: Jung Pyo Seo, Sung Ho JangAbstract:Many diffusion tensor tractography (DTT) studies have reported on the topography of transcallosal fibers (TCF). However, little detailed anatomical information on TCF that can be easily applied for clinical purposes is known. Using probabilistic DTT, we attempted to determine the anatomical location of the TCF for motor and sensory function in the human brain. A total of 51 healthy subjects were recruited for this study. Diffusion tensor images (DTIs) were obtained at 1.5 T, and four TCF for the premotor cortex (PMC), the primary motor cortex (M1) for hand and leg, and the primary somatosensory cortex (S1) were obtained using FMRIB software. Locations of the TCF were defined as the highest probabilistic location on the midsagittal slice of the corpus callosum. We measured distances between the most anterior and posterior points of the corpus callosum. The relative mean distances of the highest probabilistic location for the precentral knob PMC (Brodmann Area 6 anterior to the precentral knob), hand M1, leg M1, and precentral knob S1 (postcentral gyrus posterior to the precentral knob) TCF were 48.99%, 59.78%, 67.93%, and 73,48% from the most anterior point of the CC, respectively. According to our findings, the precentral knob PMC, hand M1, leg M1, and precentral knob S1 TCF were located at the anterior body, posterior body, posterior body, and isthmus according to Witelson’s classification, respectively.
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Corticoreticular pathway in the human brain: Diffusion tensor tractography study
Neuroscience letters, 2011Co-Authors: Sang Seok Yeo, Min Cheol Chang, Yong Hyun Kwon, Young Jin Jung, Sung Ho JangAbstract:The corticoreticular pathway (CRP) is involved in postural control and locomotor function. No study has been conducted for identification of the CRP in the human brain. In the current study, we attempted to identify the CRP in the human brain, using diffusion tensor tractography (DTT). We recruited 24 healthy volunteers for this study. Diffusion tensor images were scanned using 1.5-T. For reconstruction of the CRP, a seed region of interest (ROI) was placed on the reticular formation of the medulla. The first target ROI was placed on the midbrain tegmentum and the second target ROI was placed on the premotor cortex (Brodmann Area 6). Values of fractional anisotropy, mean diffusivity, and tract volume of the CRP were measured. The CRP, which originated from the premotor cortex, descended through the corona radiata and the posterior limb of the internal capsule anterior to the corticospinal tract. In the midbrain and pons, it passed through the tegmentum and terminated at the pontomedullary reticular formation. No differences in terms of fractional anisotropy, mean diffusivity, and tract volume were observed between hemispheres (P>0.05). We identified the CRP in the human brain using DTT. These methods and results would be helpful to both clinicians and researchers in the neuroscience field.
Sebastian Walther - One of the best experts on this subject based on the ideXlab platform.
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Functional and structural correlates of abnormal involuntary movements in psychosis risk and first episode psychosis.
Schizophrenia research, 2019Co-Authors: Jochen Kindler, Chantal Michel, Frauke Schultze-lutter, Gwendolin Felber, Martinus Hauf, Benno G. Schimmelmann, Michael Kaess, Daniela Hubl, Sebastian WaltherAbstract:Abstract Background Abnormal involuntary movements (AIM) may occur throughout the course of psychosis. While AIM are thought to indicate striatal abnormalities, the functional and structural correlates of increased AIM remain elusive. Here, we examined the prevalence of AIM in patients with clinical high risk for psychosis (CHR), first episode psychosis (FEP) and clinical controls (CC). Furthermore, we tested the association of AIM with regional cerebral blood flow (rCBF), grey matter volume (GMV), and premorbid IQ. Methods We conducted a video-based analysis of AIM in patients with CHR (n = 45), FEP (n = 10) and CC (n = 39), recruited in the Early Detection and Intervention Center, Bern. Premorbid intelligence was evaluated using the Peabody Picture Vocabulary test. Additionally, arterial spin labeling MRIs and structural MRIs were acquired in a subgroup of the sample to investigate the association of AIM with rCBF and GMV. Results Higher total AIM scores were detected in CHR (p = 0.02) and FEP (p = 0.04) as compared to CC. When separated for different muscle groups, lips and perioral movements were significantly increased in CHR patients as compared to CC (p = 0.009). AIM scores correlated positively with rCBF in the premotor cortex, Brodmann Area 6 (p Conclusions AIM were more frequent in the psychosis spectrum than in clinical controls. Neuroimaging findings indicate an involvement of cortical motor Areas in abnormal motor behavior, instead of pure basal ganglia pathology.
C D Frith - One of the best experts on this subject based on the ideXlab platform.
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functional localization of the system for visuospatial attention using positron emission tomography
Brain, 1997Co-Authors: Anna C Nobre, G N Sebestyen, Darren R Gitelman, Marsel M Mesulam, R S J Frackowiak, C D FrithAbstract:PET was used to image the neural system underlying visuospatial attention. Analysis of data at both the group and individual-subject level provided anatomical resolution superior to that described to date. Six right-handed male subjects were selected from a pilot behavioural study in which behavioural responses and eye movements were recorded. The attention tasks involved covert shifts of attention, where peripheral cues indicated the location of subsequent target stimuli to be discriminated. One attention condition emphasized reflexive aspects of spatial orientation, while the other required controlled shifts of attention. PET activations agreed closely with the cortical regions recently proposed to form the core of a neural network for spatial attention. The two attention tasks evoked largely overlapping patterns of neural activation, supporting the existence of a general neural system for visuospatial attention with regional functional specialization. Specifically, neocortical activations were observed in the right anterior cingulate gyrus (Brodmann Area 24), in the intraparietal sulcus of right posterior parietal cortex, and in the mesial and lateral premotor cortices (Brodmann Area 6).
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Functional localization of the system for visuospatial attention using positron emission
1997Co-Authors: G N Sebestyen, Darren R Gitelman, Marsel M Mesulam, R S J Frackowiak, C D Frith, Anna C NobreAbstract:Summary PET was used to image the neural system underlying agreed closely with the cortical regions recently proposed to form the core of a neural network for spatial attention. The visuospatial attention. Analysis of data at both the group and individual-subject level provided anatomical resolution two attention tasks evoked largely overlapping patterns of neural activation, supporting the existence of a general neural superior to that described to date. Six right-handed male subjects were selected from a pilot behavioural study in which system for visuospatial attention with regional functional specialization. Specifically, neocortical activations were behavioural responses and eye movements were recorded. The attention tasks involved covert shifts of attention, where observed in the right anterior cingulate gyrus (Brodmann Area 24), in the intraparietal sulcus of right posterior parietal peripheral cues indicated the location of subsequent target stimuli to be discriminated. One attention condition cortex, and in the mesial and lateral premotor cortices (Brodmann Area 6). emphasized reflexive aspects of spatial orientation, while the other required controlled shifts of attention. PET activations
Anna C Nobre - One of the best experts on this subject based on the ideXlab platform.
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functional localization of the system for visuospatial attention using positron emission tomography
Brain, 1997Co-Authors: Anna C Nobre, G N Sebestyen, Darren R Gitelman, Marsel M Mesulam, R S J Frackowiak, C D FrithAbstract:PET was used to image the neural system underlying visuospatial attention. Analysis of data at both the group and individual-subject level provided anatomical resolution superior to that described to date. Six right-handed male subjects were selected from a pilot behavioural study in which behavioural responses and eye movements were recorded. The attention tasks involved covert shifts of attention, where peripheral cues indicated the location of subsequent target stimuli to be discriminated. One attention condition emphasized reflexive aspects of spatial orientation, while the other required controlled shifts of attention. PET activations agreed closely with the cortical regions recently proposed to form the core of a neural network for spatial attention. The two attention tasks evoked largely overlapping patterns of neural activation, supporting the existence of a general neural system for visuospatial attention with regional functional specialization. Specifically, neocortical activations were observed in the right anterior cingulate gyrus (Brodmann Area 24), in the intraparietal sulcus of right posterior parietal cortex, and in the mesial and lateral premotor cortices (Brodmann Area 6).
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Functional localization of the system for visuospatial attention using positron emission
1997Co-Authors: G N Sebestyen, Darren R Gitelman, Marsel M Mesulam, R S J Frackowiak, C D Frith, Anna C NobreAbstract:Summary PET was used to image the neural system underlying agreed closely with the cortical regions recently proposed to form the core of a neural network for spatial attention. The visuospatial attention. Analysis of data at both the group and individual-subject level provided anatomical resolution two attention tasks evoked largely overlapping patterns of neural activation, supporting the existence of a general neural superior to that described to date. Six right-handed male subjects were selected from a pilot behavioural study in which system for visuospatial attention with regional functional specialization. Specifically, neocortical activations were behavioural responses and eye movements were recorded. The attention tasks involved covert shifts of attention, where observed in the right anterior cingulate gyrus (Brodmann Area 24), in the intraparietal sulcus of right posterior parietal peripheral cues indicated the location of subsequent target stimuli to be discriminated. One attention condition cortex, and in the mesial and lateral premotor cortices (Brodmann Area 6). emphasized reflexive aspects of spatial orientation, while the other required controlled shifts of attention. PET activations
