Search results for "Brain Mapping"
showing 10 items of 396 documents
Central opioidergic neurotransmission in complex regional pain syndrome
2010
Objective: Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by sensory, motor, and autonomic symptoms. It develops after limb trauma and may be associated with relevant psychiatric comorbidity. As there is evidence for central pathophysiology which might be related to an altered opioidergic neurotransmission, we investigated the cerebral opioid receptor status under resting conditions in this patient population.Methods: In this case-control study, 10 patients with CRPS and 10 age- and gender-matched healthy subjects underwent a PET scan using the subtype-nonselective opioidergic radioligand [18F]fluoroethyl-diprenorphine. As a surrogate for regional cerebral o…
Brain atrophy and lesion load in a large population of patients with multiple sclerosis
2005
Objective: To measure white matter (WM) and gray matter (GM) atrophy and lesion load in a large population of patients with multiple sclerosis (MS) using a fully automated, operator-independent, multiparametric segmentation method. Methods: The study population consisted of 597 patients with MS and 104 control subjects. The MRI parameters were abnormal WM fraction (AWM-f), global WM-f (gWM-f), and GM fraction (GM-f). Results: Significant differences between patients with MS and control subjects included higher AWM-f and reduced gWM-f and GM-f. MRI data showed significant differences between patients with relapsing-remitting and secondary progressive forms of MS. Significant correlations bet…
Topodiagnostic implications of hemiataxia: An MRI-based brainstem mapping analysis
2007
The topodiagnostic implications of hemiataxia following lesions of the human brainstem are only incompletely understood. We performed a voxel-based statistical analysis of lesions documented on standardised MRI in 49 prospectively recruited patients with acute hemiataxia due to isolated unilateral brainstem infarction. For statistical analysis individual MRI lesions were normalised and imported in a three-dimensional voxel-based anatomical model of the human brainstem. Statistical analysis revealed hemiataxia to be associated with lesions of three distinct brainstem areas. The strongest correlation referred to ipsilateral rostral and dorsolateral medullary infarcts affecting the inferior ce…
A new method to investigate brain stem structural-functional correlations using digital post-processing MRI - reliability in ischemic internuclear op…
2001
We investigated the reliability of a new digital post-processing magnetic resonance imaging (MRI) technique in ischemic brain stem lesions to identify relations of the lesion to anatomical brain stem structures. The target was a medial longitudinal fasciculus (MLF) lesion, which was evident from ipsilateral internuclear ophthalmoplegia (INO). Sixteen patients with acute unilateral INO and an isolated acute brain stem lesion in T2- and EPI-diffusion weighted MRI within 2 days after the onset of symptoms were studied. The MRI slice direction was parallel and perpendicular to a slice selection of a stereotactic anatomical atlas. The individual slices were normalized and projected in the digita…
MRI pattern recognition in multiple sclerosis normal-appearing brain areas
2011
ObjectiveHere, we use pattern-classification to investigate diagnostic information for multiple sclerosis (MS; relapsing-remitting type) in lesioned areas, areas of normal-appearing grey matter (NAGM), and normal-appearing white matter (NAWM) as measured by standard MR techniques.MethodsA lesion mapping was carried out by an experienced neurologist for Turbo Inversion Recovery Magnitude (TIRM) images of individual subjects. Combining this mapping with templates from a neuroanatomic atlas, the TIRM images were segmented into three areas of homogenous tissue types (Lesions, NAGM, and NAWM) after spatial standardization. For each area, a linear Support Vector Machine algorithm was used in mult…
Brain response to masked and unmasked facial emotions as a function of implicit and explicit personality self-concept of extraversion.
2016
Extraversion-introversion is a personality dimension referring to individual differences in social behavior. In the past, neurobiological research on extraversion was almost entirely based upon questionnaires which inform about the explicit self-concept. Today, indirect measures are available that tap into the implicit self-concept of extraversion which is assumed to result from automatic processing functions. In our study, brain activation while viewing facial expression of affiliation relevant (i.e., happiness, and disgust) and irrelevant (i.e., fear) emotions was examined as a function of the implicit and explicit self-concept of extraversion and processing mode (automatic vs. controlled…
Quantifying changes in EEG complexity induced by photic stimulation.
2009
Summary Objectives: This study aims to characterize EEG complexity, measured as the prediction error resulting from nonlinear prediction, in healthy humans during photic stimulation. Methods: EEGs were recorded from 15 subjects with eyes closed (EC) and eyes open (EO), during the baseline condition and during stroboscopic photic stimulation (PS) at 5, 10, and 15 Hz. The mean squared prediction error (MSPE) resulting from nearest neighbor local linear prediction was taken as complexity index. Complexity maps were generated interpolating the MSPE index over a schematic scalp representation. Results: Statistical analysis revealed that: i) EEG shows good predictability in all conditions and see…
Dipole Source Analyses of Early Median Nerve SEP Components Obtained From Subdural Grid Recordings
2010
The median nerve N20 and P22 SEP components constitute the initial response of the primary somatosensory cortex to somatosensory stimulation of the upper extremity. Knowledge of the underlying generators is important both for basic understanding of the initial sequence of cortical activation and to identify landmarks for eloquent areas to spare in resection planning of cortex in epilepsy surgery. We now set out to localize the N20 and P22 using subdural grid recording with special emphasis on the question of the origin of P22: Brodmann area 4 versus area 1. Electroencephalographic dipole source analysis of the N20 and P22 responses obtained from subdural grids over the primary somatosensor…
Differences in the topographical distribution of EEG activity during surgical anaesthesia and on emergence from volatile anesthetics.
1994
Computerized processing of a 16 channel EEG allows mapping and display of cortical electrical activity in a useful mode for intraoperative monitoring. We studied the topographical distribution of EEG-activity displayed as spectral maps comparing inhalational anaesthesia with isoflurane or enflurane during surgical anaesthesia and emergence. Two groups of nine patients each were anaesthetized with one of the two regimens. The EEG patterns during steady state end-tidal concentrations of isoflurane (0.7-1.1%) or enflurane (0.8-1.3%) showed highest activity in the frontal and occipital areas. At near awakening the frontal and occipital dominance of delta activity disappeared in both groups and …
Straight gyrus morphology in first-episode schizophrenia-spectrum patients
2010
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