ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

We present an fMRI-based method that enables subjects to monitor and actively modulate their own brain activity as a form of biofeedback. On a 1.5 T clinical MR scanner, functional areas during a simple hand motor task were delineated by detecting signal variations associated with the brain activity. Then, the subject adopted a different strategy to expand the activation in motor and somatosensory areas that were not activated previously. Statistical maps of brain activity were visually presented back to the subject, being updated at the end of each segmented rest-task block in near real-time manner. Our results suggest that the visual feedback of the functional brain activation maps guided subjects to adjust their task performance to achieve the desired modulation of cortical activity. This method may offer a potential utility for fMRI-based neurofeedback.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Expectations about future events are known to trigger neural mechanisms that affect both perception and action. Here we report that different and opposite expectations of bad and good motor performance modulate the therapeutic effects of subthalamic nucleus stimulation in Parkinsonian patients who had undergone chronic implantation of electrodes for deep brain stimulation. By analyzing the effects of subthalamic stimulation on the velocity of movement of the right hand, we found hand movement to be faster when the patients expected a good motor performance. The expectation of good performance was induced through a placebo-like procedure, thus indicating that placebo-induced expectations have influence on the treatment outcome. All these effects occurred within minutes, suggesting that expectations induce neural changes very quickly.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Sleep deprivation by the disk-over-water technique results in a predictable syndrome of physiological changes in rats. It has been proposed that reactive oxygen species (ROS) may be responsible for some of these effects. A variety of antioxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) help to regulate the level of ROS. In this study we investigated the effects of prolonged (5–11 days) sleep deprivation on the activities of SOD and GPx as well as the metabolic activity of the mitochondria (using alamar blue) in several brain regions (cortex, hippocampus, hypothalamus, brainstem and cerebellum). We show that prolonged sleep deprivation significantly decreased Cu/Zn-SOD activity in the hippocampus and brainstem, suggesting an alteration in the metabolism of ROS resulting in oxidative stress.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The effect of traumatic spinal cord injury (SCI) on the expression of tumor necrosis factor (TNF&agr;) and its mRNA was examined. Quantitative reverse transcription polymerase chain reaction assay showed TNF&agr; mRNA level increased > 20-fold at the lesion site by 1 h after the injury compared to that in uninjured controls. The TNF&agr; mRNA level was still significantly higher than in the controls 72 h after the injury. TNF&agr; mRNA in the samples collected immediately caudal to the lesion site was also increased. Levels of TNF&agr; protein, determined by a cytotoxic bioassay, were also significantly increased at the lesion site. The TNF&agr; protein level was maximal 1 and 8 h after the injury and still significantly higher than in the controls 24 h post-injury. The present results demonstrate that TNF&agr; is rapidly induced in the spinal cord after the injury, and it may play a significant role in secondary events in SCI.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Cholinergic basal forebrain neurons (CBFN) expressing the low-affinity neurotrophin receptor p75 (p75NTR) were previously selectively labeledin vivowith carbocyanine 3 (Cy3)-tagged anti-p75NTR, but the applied 192IgG-conjugates recognized p75NTRonly in rat. The antibody ME 20.4 raised against human p75NTRhad been shown to cross-react with the receptor in monkey, raccoon, sheep, cat, dog, pig and rabbit. Hence, forin vivolabeling of rabbit CBFN in the present study, ME 20.4 was fluorochromated with Cy3-N-hydroxysuccinimide ester and purified Cy3-ME 20.4 was injected intracerebroventricularly. Two days post-injection, clusters of Cy3-ME 20.4 were found in CBFN displaying choline acetyltrans-ferase-immunoreactivity. Following photoconversion, electron microscopy revealed fluorochromated antibodies in secondary lysosomes. In conclusion, Cy3-ME 20.4 might become an appropriate marker for CBFN in live and fixed tissues of various mammalian species.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Form and motion coherence was tested in children with dyspraxia and matched controls to assess their global spatial and global motion processing abilities. Thresholds for detecting form coherence patterns were significantly higher in the dyspraxic group than in the control group. No corresponding difference was found on the motion coherence task. We tested eight children with dyspraxic disorder (mean age 8.2 years) and 50 verbal-mental-age matched controls (mean age 8.4 years) to test for a neural basis to the perceptual abnormalities observed in dyspraxia. The results provide evidence that children with dyspraxia have a specific impairment in the global processing of spatial information. This finding contrasts with other developmental disorders such as Williams syndrome, autism and dyslexia where deficits have been found in global motion processing and not global form processing. We conclude that children with dyspraxia may have a specific occipitotemporal deficit and we argue that testing form and motion coherence thresholds might be a useful diagnostic tool for the often coexistent disorders of dyspraxia and dyslexia.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Alzheimer disease (AD) risk is significantly influenced by the APOE2 and APOE4 alleles. In turn, the −491AT and TH1/E47cs polymorphisms alter APOE gene expression levels. To determine whether these two alleles exert any significant effect on AD development we have analysed the genotypes of the APOE promoter −491AT and Th1/E47cs polymorphisms in 163 AD patients and 155 controls divided into three age at onset/age dependent subgroups. Our study has detected a Th1/E47cs-T allele accumulation in healthy individuals over 75 years of age, which suggests it plays a protective role against AD. The Th1/E47cs-T allele may provide greater protection against AD than APOE2, although this awaits proof of Th1/E47cs-T allele overrepresentation in healthy individuals of other populations.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Experimental allergic encephalomyelitis (EAE), a model of multiple sclerosis, is an autoimmune, demyelinating disease of the CNS. Pro-inflammatory cytokines (e.g. tumour necrosis factor-&agr; (TNF-&agr;) and interleukin (IL)-12) and reactive oxygen species are implicated in promoting EAE. Since histamine H2receptor activation suppresses production of O2.−, TNF-&agr;, and IL-12 by inflammatory cells, we tested the hypothesis that dimaprit, an H2agonist, would reduce the clinical severity and pathology of EAE. Dimaprit treatment significantly reduced clinical signs compared to vehicle in both C57BL/6 and iNOS deficient EAE mice. Furthermore, dimaprit significantly reduced CNS staining for lectin-positive macrophages and decreased extravasated albumin staining, an indicator of blood–brain barrier leakage. These data provide a rationale for exploring H2receptor activation for therapeutic value in multiple sclerosis.

ISSN:0959-4965    

出版商:OVID    

年代:2002

数据来源: OVID