Search results for " Brain"
showing 10 items of 985 documents
Structure, chromosomal localization, and brain expression of human Cx36 gene
1999
Rat connexin-36 (Cx36) is the first gap junction protein shown to be expressed predominantly in neuronal cells of the mammalian central nervous system. As a prerequisite for studies devoted to the investigation of the possible role of this connexin in human neurological diseases, we report the cloning and sequencing of the human Cx36 gene, its chromosomal localization, and its pattern of expression in the human brain analyzed by radioactive in situ hybridization. The determination of the human gene sequence revealed that the coding sequence of Cx36 is highly conserved (98% identity at the protein level with the mouse and rat Cx36 and 80% with the ortholog perch and skate Cx35), and that the…
Reference interval determination for N-terminal-B-type natriuretic peptide (NT-proBNP): A study in blood donors
2005
We assessed reference values in a group of apparently healthy blood donors. A total of 1980 blood donors was recruited and tested for the presence of NT-proBNP using a newly developed electrochemiluminescence immunoassay (ECLIA) method. NT-proBNP clustered in all blood donors below the age of 50 years and an upper limit of normal (ULN) was found to be 84 pg/ml for males and 146 pg/ml for females. Mean NT-proBNP values increased with increasing age which was due to an increasing number of individuals exceeding the ULN. Age- and gender-appropriate NT-proBNP levels decreased with increasing hemoglobin levels. Hemoglobin but not creatinine levels influenced the NT-proBNP concentration in this c…
Repetitive TMS of cerebellum interferes with millisecond time processing
2007
Time processing is important in several cognitive and motor functions, but it is still unclear how the human brain perceives time intervals of different durations. Processing of time in millisecond and second intervals may depend on different neural networks and there is now considerable evidence to suggest that these intervals are possibly measured by independent brain mechanisms. Using repetitive transcranial magnetic stimulation (rTMS), we determined that the cerebellum is essential in explicit temporal processing of millisecond time intervals. In the first experiment, subjects' performance in a time reproduction task of short (400-600 ms) and long (1,600-2,400 ms) intervals, were evalua…
Reduced cerebellar inhibition in migraine with aura: a TMS study.
2009
Subtle clinical cerebellar alterations have been found in migraine. Moreover, abnormalities in visual and motor cortex excitability consistent with a lack of inhibitory efficiency have been described in migraine, and it is known that cerebellum exerts an inhibitory control on cerebral cortex. Here, we investigated if impairment of cerebellar activity on motor cortex, i.e. reduced inhibitory control, can be found in migraine. Ten migraineurs with aura and seven healthy controls underwent a transcranial magnetic stimulation (TMS) protocol to investigate the cerebellar inhibitory drive on motor cortex: a conditioning pulse on right cerebellar cortex was delivered 5, 7, 10, 15 ms before a test …
Cerebellar, but not Motor or Parietal, High-Density Anodal Transcranial Direct Current Stimulation Facilitates Motor Adaptation.
2016
AbstractObjectives: Although motor adaptation is a highly relevant process for both everyday life as well as rehabilitation many details of this process are still unresolved. To evaluate the contribution of primary motor (M1), parietal and cerebellar areas to motor adaptation processes transcranial direct current stimulation (tDCS) has been applied. We hypothesized that anodal stimulation of the cerebellum and the M1 improves the learning process in mirror drawing, a task involving fine grained and spatially well-organized hand movements. Methods: High definition tDCS (HD-tDCS) allows a focal stimulation to modulate brain processes. In a single-session double-blind study, we compared the ef…
Development and validation of a reliable method for studying the distribution pattern for opiates metabolites in brain
2012
Abstract Brain distribution pattern of “street” heroin metabolites (morphine and codeine) was investigated in two fatalities due to “acute narcotism”. A suitable sample pretreatment prior to solid-phase-extraction was developed to achieve a good recovery of the analytes and to eliminate the interfering species. After derivatization with MSTFA, samples were analyzed by GC/MS. Specificity, accuracy, precision and linearity of the method were evaluated; LOD and LOQ were, respectively, 10 ng/25 ng for morphine and 5 ng/10 ng for codeine. This method was applied to the analysis of six brain areas (hippocampus, frontal lobe, occipital lobe, nuclei, bulb and pons) coming from two cases of heroin-r…
The Neural Correlates of Grammatical Gender: An fMRI Investigation
2002
Abstract In an fMRI experiment, subjects saw a written noun and made three distinct decisions in separate sessions: Is its grammatical gender masculine or feminine (grammatical feature task)? Is it an animal or an artifact (semantic task)? Does it contain a /tch/ or a /k/ sound (phonological task)? Relative to the other experimental conditions, the grammatical feature task activated areas of the left middle and inferior frontal gyrus and of the left middle and inferior temporal gyrus. These activations fit in well with neuropsychological studies that document the correlation between left frontal lesions and damage to morphological processes in agrammatism, and the correlation between left t…
Time and spatial attention: Effects of prism adaptation on temporal deficits in brain damaged patients
2011
Growing evidence indicates that the representations of space and time interact in the brain but the exact neural correlates of such interaction remain unknown. Neuroimaging and neuropsychological studies show that processing of temporal information engages a distributed network in the right hemisphere and suggest a link between deficits in spatial attention and deficits in time perception. In the present study we used the procedure of prismatic adaptation (PA) to directionally manipulate spatial attention in order to explore the effect of attentional deviation on time perception in patients with right (RBD) vs. left (LBD) brain damage. In a first experiment, two groups of RBD and LBD patien…
Asymmetry in the human primary somatosensory cortex and handedness.
2003
Brain asymmetry is a phenomenon well known for handedness and language specialization and has also been studied in motor cortex. Less is known about hemispheric asymmetries in the somatosensory cortex. In the present study, we systematically investigated the representation of somatosensory function analyzing early subcortical and cortical somatosensory-evoked potentials (SEP) after electrical stimulation of the right and left median nerve. In 16 subjects, we compared thresholds, the peripheral neurogram at Erb point, and, using MRI-based EEG source analysis, the P14 brainstem component as well as N20 and P22, the earliest cortical responses from the primary sensorimotor cortex. Handedness w…
Alterations of Continuous MEG Measures during Mental Activities
2000
In a pilot study, we investigated the topography of 11 continuous MEG measures for the eyes-opened and eyes-closed condition together with three simple mental tasks (mental arithmetic, visual imagery, word generation). One-minute recordings for each condition from 16 right-handed subjects were analyzed. The electrophysiological measures consisted of 6 spectral band measures together with spectral edge frequency and spectral entropy, plus the time-domain-based entropy of amplitudes (ENA) and the nonlinear measures correlation dimension D2 and Lyapunov exponent L1. In summary, our results indicate a pronounced task-dependent difference between the anterior and the posterior region, but no lat…