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11. |
Acute plasticity in the human somatosensory cortex following amputation |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1013-1017
David Borsook,
Lino Becerra,
Scott Fishman,
Annabel Edwards,
Candice Jennings,
Milan Stojanovic,
Lito Papinicolas,
Vilayanur Ramachandran,
R Gonzalez,
Hans Breiter,
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摘要:
WE studied a patient after amputation of an arm and found that in less than 24 h stimuli applied on the ipsilateral face were referred in a precise, topographically organized, modality-specific manner to distinct points on the phantom. Functional magnetic resonance imaging (fMRI) performed one month later showed that brush-evoked activity in the brain demonstrates objective signal changes which correlate with perceptual changes in the phantom hand. This finding in humans corresponds to the observations of immediate plasticity in cortical pathways described in animals, including primates. The results suggest that reorganization of sensory pathways occurs very soon after amputation in humans, potentially due to the unmasking of ordinarily silent inputs rather than sprouting of new axon terminals.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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12. |
The functional anatomy of imagining and perceiving colour |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1019-1023
R Howard,
D ffytche,
J Barnes,
D McKeefry,
Y Ha,
P Woodruff,
E Bullmore,
A Simmons,
S Williams,
A David,
M Brammer,
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摘要:
WE report two functional magnetic resonance imaging experiments which reveal similarities and differences between perceptual and imaginal networks within the single visual submodality of colour. The first experiment contrasted viewing of a coloured and grey-scale Mondrian display, while the second contrasted a relative colour judgement with a spatial task and required the generation of mental images. Our results show that colour perception activates the posterior fusiform gyrus bilaterally (area V4), plus right-sided anterior fusiform and lingual gyri, striate cortex (area V1), and the left and right insula. Colour imagery activated right anterior fusiform gyrus, left insula, right hippocampus and parahippocampal gyrus, but not V4 or V1. The findings reconcile neurological case studies suggesting a double dissociation between deficits in colour imagery and perception and point to anterior fusiform, parahippocampal gyri and hippocampus as the location for stored representations of coloured objects.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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13. |
Relationship between anxiety and serotonin in the ventral striatum |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1025-1029
Rainer Schwarting,
Christiane Thiel,
Christian Müller,
Joseph Huston,
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摘要:
Rats were tested in an elevated plus-maze on two consecutive days. Based on the percentage of time spent in the open arms on the 1st day, they were divided into two subgroups with either low or high anxiety levels. A post-mortem neurochemical analysis showed that animals with high anxiety had lower ventral striatal tissue levels of 5-HT. No such differences were found for 5-HT in other brain areas or in dopamine and norepinephrine levels. The ventral striatal 5-HT levels correlated with plus-maze behavior on the 2nd but not 1st day. These data suggest that individual differences in ventral striatal 5-HT interact with plus-maze behavior, which may help to explain why serotonergic drugs can have inconsistent effects in this paradigm.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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14. |
Immunofluorescent identification of endomorphin‐2‐containing nerve fibers and terminals in the rat brain and spinal cord |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1031-1034
Matthias Schreff,
Stefan Schulz,
Dana Wiborny,
Volker Höllt,
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摘要:
Endomorphin-1 and −2 are potent and selective agonists for the μ-opioid receptor which have recently been isolated from bovine brain extracts. In the present study we used polyclonal antibodies specific for endomorphin-2 to determine its immunocytochemical distribution in the rat brain and spinal cord Endomorphin-2-like immunoreactivity was confined to varicose fibers with an overall discrete distribution within the central nervous system. The immunostaining was completely abolished by preincubation of the antiserum with endomorphin-2 but not with endomorphin-1. Endomorphin-2-like immunoreactivity was enriched in many but not all brain regions known to contain dense μ-opioid receptors, including nucleus accumbens, septum, midline thalamic nuclei, hypothalamic and amygdala nuclei, locus coeruleus, periaqueductal gray and spinal cord dorsal horn. In contrast, endomorphin-2 was absent from the cortex, striatum, hippocampus, nucleus of the solitary tract and dorsal root ganglia. Dual-labeling experiments revealed that endomorphin-2-immunoreactive nerve fibers did not co-contain any other opioid peptide. Thus, the present findings strongly suggest that endomorphin-2 may be a natural ligand for the μ-opioid receptor likely to be involved in the modulation of nociceptive transmission and reward-seeking behavior.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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15. |
Differential interactions of MAP2, tau and MAP5 during axogenesis in culture |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1035-1040
Stephanie Kwei,
Albrecht Clement,
Andreas Faissner,
Roland Brandt,
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摘要:
THE subcellular interactions of the neuronal microtubule-associated proteins tau, MAP2 and MAP5 were determined in cultured rat hippocampal neurons using differential detergent extraction and laser scanning microscopy. Axon development correlated with a transition from a MAP2-actin filament interaction to a MAP2-microtubule association and binding of tau to the distal axon. Tau and MAP2 binding specifically increased in the axon and the minor neurites, respectively. No compartment-specific association of MAP5 was observed. Tau binding preceded the accumulation of microtubules at the distal axon which represented a characteristic event during axogenesis. The data provide evidence for a role of MAP2 in regulating microfilament-microtubule interactions during neurite formation and of tau in organizing microtubules at the distal axon.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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16. |
Human hippocampal long‐term sustained response during word memory processing |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1041-1047
Toshinori Kato,
Peter Erhard,
Yoshihiro Takayama,
John Strupp,
Tuong Le,
Seiji Ogawa,
Kamil Ugurbil,
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摘要:
Temporal behavior of activation associated with the neural substrate of human memory function was investigated during and after an auditorily instructed word memory task using multislice functional magnetic resonance imaging. The hippocampal formation, which is involved in human memory function, displayed a long-term sustained response that persisted significantly (∼90 s) beyond the duration of the memory task. This sustained period was ∼two-fold longer than the duration of the post-task activation observed in auditory areas and Broca's area, which are involved in the phonological loop of the verbal working memory. These observations suggest that the hippocampal memory processing involves sustained activation in the transitional function for the long-term memory over the working memory period.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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17. |
Bcl‐2 and Bax protein expression in neurofibrillary tangles in progressive supranuclear palsy |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1049-1052
Avelina Tortosa,
Rosa Blanco,
Isidre Ferrer,
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摘要:
Double-Labeling immunohistochemistry to Bcl-2 and Bax and to tau protein was examined in the brains of patients with progressive supranuclear palsy (PSP) to study the possible relationship between the expression of Bax and Bcl-2 proteins and neurofibrillary tangle formation. No differences between Bcl-2 and Bax immunoreactivity in neurons of the brain stem were observed in PSP patients and controls. Moreover, the intensity of Bcl-2 and Bax immunoreactivity was similar in tangle-bearing and non-tangle-bearing neurons in PSP patients. These results suggest that Bcl-2 and Bax are probably not implicated in neurofibrillary tangle formation in PSP.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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18. |
Expression of an oscillating interferon‐γ receptor in the suprachiasmatic nuclei |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1059-1063
Gabriella Lundkvist,
Brita Robertson,
Jama Mhlanga,
Martin Rottenberg,
Krister Kristensson,
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摘要:
THE suprachiasmatic nuclei serve as the dominant circadian pacemaker in the mammalian brain, regulating daily behavioral, physiological and hormonal rhythms. In the ventrolateral parts of these nuclei, the receptor for the key immunoregulatory molecule interferon-γ (IFN-γ) was detected in the rat brain. The cellular localization of the IFN-γ receptor corresponded to neuronal elements. Expression of the receptor followed a diurnal rhythm with a peak at zeitgeber time 15. This peak coincided with an enhanced expression of janus kinase 1 and 2 as well as the signal transducer and activator of transcription 1, which constitute the main intracellular signaling pathway of IFN-γ. This is the first study to show expression of the receptor of an immune modulatory molecule in the pacemaker of the biological clock, which, thus, may be influenced by immune system signal molecules.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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19. |
GABAAreceptor blockade inhibits Aβ fibre evoked wind‐up in the arthritic rat |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1065-1069
Han-Rong Weng,
Jennifer Laird,
Fernando Cervero,
Jens Schouenborg,
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摘要:
To clarify the mechanisms of allodynia we have examined whether ‘wind-up’ of nociceptive withdrawal reflexes (NWR), a phenomenon characteristic of nociceptive C fiber spinal processing, can be mimicked by stimulation of tactile Aβ fibers in monoarthritic decerebrate spinal rats. Knee joint monoarthritis was induced by carrageenan/kaolin under halothane anaesthesia 5 h before recordings. In arthritic, but not in control rats, wind-up of NWR of the semitendinosus muscle could be evoked by repeated stimulation of Aβ fibres. By contrast, peroneus longus reflexes did not exhibit marked wind-up. Bicuculline (0.03–0.3 mg/kg, i.v.) dose-dependently inhibited this wind-up. Hence, reflex wind-up can be elicited by tactile Aβ fibers in arthritic rats through a GABAAdependent mechanism.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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20. |
Dextromethorphan potentiates the effect of morphine in rats with peripheral neuropathy |
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NeuroReport,
Volume 9,
Issue 6,
1998,
Page 1071-1074
Timo Kauppila,
Xiao-Jun Xu,
Wei Yu,
Zsuzsanna Wiesenfeld-Hallin,
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摘要:
NEUROPATHIC pain responds poorly to opioids. We now report that combination of systemic morphine (2 mg/kg) and dextromethorphan (45 mg/kg), a clinically available antitussive with NMDA-antagonist properties, markedly alleviated mechanical and cold allodynia-like behavior in a rat model of peripheral mononeuropathy. Neither drug produced a significant effect on its own at these doses. The anti-allodynic effect of morphine plus dextromethorphan was reversed by naloxone. The present results suggest that a combination of NMDA-antagonist and opiates might be effective in treating neuropathic pain. Furthermore, the effect of this drug combination is mainly mediated via opioid receptors.
ISSN:0959-4965
出版商:OVID
年代:1998
数据来源: OVID
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