The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
B Saletu - One of the best experts on this subject based on the ideXlab platform.
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low resolution brain electromagnetic tomography revealed simultaneously active frontal and parietal sleep spindle sources in the human cortex
Neuroscience, 2001Co-Authors: P Anderer, Gerhard Klosch, Georg Gruber, E Trenker, Roberto D Pascualmarqui, J Zeitlhofer, M J Barbanoj, Peter Rappelsberger, B SaletuAbstract:Abstract Analyses of scalp-recorded sleep spindles have demonstrated topographically distinct slow and fast spindle waves. In the present paper, the electrical activity in the brain corresponding to different types of sleep spindles was estimated by means of low-resolution electromagnetic tomography. In its new implementation, this method is based on realistic head geometry and solution space is restricted to the cortical gray matter and hippocampus. In multichannel all-night electroencephalographic recordings, 10–20 artifact-free 1.25-s epochs with frontally, parietally and approximately equally distributed spindles were marked visually in 10 normal healthy subjects aged 20–35 years. As a control condition, artifact-free non-spindle epochs 1–3 s before or after the corresponding spindle episodes were marked. Low-resolution electromagnetic tomography demonstrated, independent of the scalp distribution, a distributed spindle source in the prefrontal cortex (Brodmann Areas 9 and 10), oscillating with a frequency below 13 Hz, and in the precuneus (Brodmann Area 7), oscillating with a frequency above 13 Hz. In extremely rare cases only the prefrontal or the parietal source was active. Brodmann Areas 9 and 10 have principal connections to the dorsomedial thalamic nucleus; Brodmann Area 7 is connected to the lateroposterior, laterodorsal and rostral intralaminar centrolateral thalamic nuclei. Thus, the localized cortical brain regions are directly connected with adjacent parts of the dorsal thalamus, where sleep spindles are generated. The results demonstrated simultaneously active cortical spindle sources which differed in frequency by approximately 2 Hz and were located in brain regions known to be critically involved in the processing of sensory input, which is in line with the assumed functional role of sleep spindles.
John R Hodges - One of the best experts on this subject based on the ideXlab platform.
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a voxel based morphometry study of semantic dementia relationship between temporal lobe atrophy and semantic memory
Annals of Neurology, 2000Co-Authors: Catherine J Mummery, R S J Frackowiak, Karalyn Patterson, C J Price, John Ashburner, John R HodgesAbstract:The cortical anatomy of 6 patients with semantic dementia (the temporal lobe variant of frontotemporal dementia) was contrasted with that of a group of age-matched normal subjects by using voxel-based morphometry, a technique that identifies changes in gray matter volume on a voxel-by-voxel basis. Among the circumscribed regions of neuronal loss, the left temporal pole (Brodmann Area 38) was the most significantly and consistently affected region. Cortical atrophy in the left hemisphere also involved the inferolateral temporal lobe (Brodmann Area 20/21) and fusiform gyrus. In addition, the right temporal pole (Brodmann Area 38), the ventromedial frontal cortex (Brodmann Area 11/32) bilaterally, and the amygdaloid complex were affected, but no significant atrophy was measured in the hippocampus, entorhinal, or caudal perirhinal cortex. The degree of semantic memory impairment across the 6 cases correlated significantly with the extent of atrophy of the left anterior temporal lobe but not with atrophy in the adjacent ventromedial frontal cortex. These results confirm that the anterior temporal lobe is critically involved in semantic processing, and dissociate its function from that of the adjacent frontal region.
P Anderer - One of the best experts on this subject based on the ideXlab platform.
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low resolution brain electromagnetic tomography revealed simultaneously active frontal and parietal sleep spindle sources in the human cortex
Neuroscience, 2001Co-Authors: P Anderer, Gerhard Klosch, Georg Gruber, E Trenker, Roberto D Pascualmarqui, J Zeitlhofer, M J Barbanoj, Peter Rappelsberger, B SaletuAbstract:Abstract Analyses of scalp-recorded sleep spindles have demonstrated topographically distinct slow and fast spindle waves. In the present paper, the electrical activity in the brain corresponding to different types of sleep spindles was estimated by means of low-resolution electromagnetic tomography. In its new implementation, this method is based on realistic head geometry and solution space is restricted to the cortical gray matter and hippocampus. In multichannel all-night electroencephalographic recordings, 10–20 artifact-free 1.25-s epochs with frontally, parietally and approximately equally distributed spindles were marked visually in 10 normal healthy subjects aged 20–35 years. As a control condition, artifact-free non-spindle epochs 1–3 s before or after the corresponding spindle episodes were marked. Low-resolution electromagnetic tomography demonstrated, independent of the scalp distribution, a distributed spindle source in the prefrontal cortex (Brodmann Areas 9 and 10), oscillating with a frequency below 13 Hz, and in the precuneus (Brodmann Area 7), oscillating with a frequency above 13 Hz. In extremely rare cases only the prefrontal or the parietal source was active. Brodmann Areas 9 and 10 have principal connections to the dorsomedial thalamic nucleus; Brodmann Area 7 is connected to the lateroposterior, laterodorsal and rostral intralaminar centrolateral thalamic nuclei. Thus, the localized cortical brain regions are directly connected with adjacent parts of the dorsal thalamus, where sleep spindles are generated. The results demonstrated simultaneously active cortical spindle sources which differed in frequency by approximately 2 Hz and were located in brain regions known to be critically involved in the processing of sensory input, which is in line with the assumed functional role of sleep spindles.
Stefan M. Golaszewski - One of the best experts on this subject based on the ideXlab platform.
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transient beneficial effects of excitatory theta burst stimulation in a patient with phonological agraphia after left supramarginal gyrus infarction
Brain and Language, 2012Co-Authors: Raffaele Nardone, Stefan M. Golaszewski, Pierpaolo De Blasi, Giulio Zuccoli, Frediano Tezzon, Eugen TrinkaAbstract:Abstract We report a patient showing isolated phonological agraphia after an ischemic stroke involving the left supramarginal gyrus (SMG). In this patient, we investigated the effects of focal repetitive transcranial magnetic stimulation (rTMS) given as theta burst stimulation (TBS) over the left SMG, corresponding to the Brodmann Area (BA) 40. The patient and ten control subjects performed a dictational words and nonwords writing task before, and 5 and 30 min after they received excitatory intermittent TBS (iTBS) over the left BA 40, the right hemisphere homologous to BA 40, the Wernicke’s Area, or the primary visual cortex. ITBS over the left SMG lead to a brief facilitation of phonological non-words writing to dictation. This case study report illustrates that rTMS is able to influence, among other language functions, the phonological loading processes during the written language production in stroke patients.
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Functional magnetic resonance imaging detects activation of the visual association cortex during laser acupuncture of the foot in humans.
Neuroscience Letters, 2002Co-Authors: Christian M. Siedentopf, Stephan Felber, Stefan M. Golaszewski, Felix M. Mottaghy, Christian C. Ruff, Andreas SchlagerAbstract:The aim of this study was to investigate the effect of laser acupuncture on cerebral activation. Using functional magnetic imaging (fMRI) cortical activations during laser acupuncture at the left foot (Bladder 67) and dummy acupuncture, were compared employing a block design in ten healthy male volunteers. All experiments were done on a 1.5 Tesla magnetic resonance scanner equipped with a circular polarized head coil. During laser acupuncture, we found activation in the cuneus corresponding to Brodmann Area (BA) 18 and the medial occipital gyrus (BA 19) of the ipsilateral visual cortex. Placebo stimulation did not show any activation. We could demonstrate that laser acupuncture of a specific acupoint, empirically related to ophthalmic disorders, leads to activation of visual brain Areas, whereas placebo acupuncture does not. These results indicate that fMRI has the potential to elucidate effects of acupuncture on brain activity.
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cognitive function and fmri in patients with multiple sclerosis evidence for compensatory cortical activation during an attention task
Brain, 2002Co-Authors: Wolfgang Staffen, Stefan M. Golaszewski, A Mair, Harald Zauner, Josef M Unterrainer, Helmut Niederhofer, A Kutzelnigg, S Ritter, Bernhard Iglseder, Gunther LadurnerAbstract:Mild cognitive impairment has frequently been reported for patients in the early stages of multiple sclerosis. The aim of the present study was to measure whether altered cortical activation during a sustained attention task occurs along with limited extent of neuropsychological problems. Expanded brain activation of multiple sclerosis patients with normal motor function compared with healthy controls during a finger tapping paradigm has previously been reported. Compensatory brain activation in patients with multiple sclerosis compared with normal controls may also be observed when the subjects are performing cognitive functions. In 21 patients with clinically definite relapsing-remitting multiple sclerosis, a psychometric assessment was performed using the Wechsler Memory Scale (WMS) and the Multiple Sclerosis Functional Composite Score (MSFC). In addition, functional MRI was performed during a Paced Visual Serial Addition Task (PVSAT), a visual analogue of the Paced Auditory Serial Addition Task (PASAT). All patients were within 3 years of diagnosis and were not suffering from a relapse at the time of investigation. The multiple sclerosis patients were compared with a control group of 21 healthy volunteers matched for handedness, age, years of education and sex. With regard to psychometric results, the WMS general memory score showed statistically significant differences between patients and controls. We did not find differences for either the MSFC or the PASAT scores. A group analysis of the functional imaging data during the PVSAT revealed different activation patterns for patients compared with control subjects. In healthy volunteers, the main activation was found in the frontal part of the right gyrus cinguli (Brodmann Area 32). In patients, the main activation was detected at the right hemispheric frontal cortex (Brodmann Areas 6, 8 and 9). In addition, the left hemispheric Brodmann Area 39 was activated. We interpret the different patterns of activation, accompanied with intact performance in a sustained attention task of our multiple sclerosis sample compared with healthy controls, as the consequence of compensatory mechanisms. This is an expression of neuronal plasticity during early stages of a chronic disease.
J Zeitlhofer - One of the best experts on this subject based on the ideXlab platform.
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low resolution brain electromagnetic tomography revealed simultaneously active frontal and parietal sleep spindle sources in the human cortex
Neuroscience, 2001Co-Authors: P Anderer, Gerhard Klosch, Georg Gruber, E Trenker, Roberto D Pascualmarqui, J Zeitlhofer, M J Barbanoj, Peter Rappelsberger, B SaletuAbstract:Abstract Analyses of scalp-recorded sleep spindles have demonstrated topographically distinct slow and fast spindle waves. In the present paper, the electrical activity in the brain corresponding to different types of sleep spindles was estimated by means of low-resolution electromagnetic tomography. In its new implementation, this method is based on realistic head geometry and solution space is restricted to the cortical gray matter and hippocampus. In multichannel all-night electroencephalographic recordings, 10–20 artifact-free 1.25-s epochs with frontally, parietally and approximately equally distributed spindles were marked visually in 10 normal healthy subjects aged 20–35 years. As a control condition, artifact-free non-spindle epochs 1–3 s before or after the corresponding spindle episodes were marked. Low-resolution electromagnetic tomography demonstrated, independent of the scalp distribution, a distributed spindle source in the prefrontal cortex (Brodmann Areas 9 and 10), oscillating with a frequency below 13 Hz, and in the precuneus (Brodmann Area 7), oscillating with a frequency above 13 Hz. In extremely rare cases only the prefrontal or the parietal source was active. Brodmann Areas 9 and 10 have principal connections to the dorsomedial thalamic nucleus; Brodmann Area 7 is connected to the lateroposterior, laterodorsal and rostral intralaminar centrolateral thalamic nuclei. Thus, the localized cortical brain regions are directly connected with adjacent parts of the dorsal thalamus, where sleep spindles are generated. The results demonstrated simultaneously active cortical spindle sources which differed in frequency by approximately 2 Hz and were located in brain regions known to be critically involved in the processing of sensory input, which is in line with the assumed functional role of sleep spindles.
