ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Recent evidence suggests that the expression of GABAAreceptor subunits is determined by an early innate program which can be further modified by thalamic input and local factors. We analyzed the GABAAsubunit distribution in experimentally induced subcortical heterotopia which are a subgroup of neuronal migration disorders. Heterotopias consist of clusters of neurons which have stopped migration early, before they have reached their final commitment and well before thalamic afferents have reached their targets. Immuno- histochemical analyses of five important GABAAreceptor subunits revealed an expression pattern typical for upper cortical layers reflecting the original commitment of the heterotopic neurons. These results point towards detailed innate determinants of cell fate which even contain information on receptor subunit distribution and are not affected by ectopic positioning.

ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Naturally induced possession trances have been observed in healthy people of many societies. The neurophysiological basis of this phenomenon remains unknown, however, because of the difficulty in accessing subjects in trances due to their sacred context. In the present study, we measured the plasma levels of several neuroactive substances from subjects exhibiting or lacking possession trance characteristics during Balinese ded- icatory dramas under natural conditions. The trance group exhibited significant increases in plasma concentrations of noradrenaline, dopamine and β-endorphin, compared with controls who performed the same actions as the trance group. The present finding suggests that catecholamines and opioid peptides are involved in possession trances.

ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Rats were trained to discriminate a 0° stripe from a 90° stripe in a two choice water maze. They were prepared with either Te2/3, partial striate (PS), or sham lesions and retrained on the preoperative discrimination. In two separate experiments, excellent savings was observed for all groups. Next, trials were administered with novel stripe orientations defined as either between- or within-category problems. Performance accuracy eroded rapidly for all groups in the first experiment, and no between-group differences were observed. In the second experiment, each session with categorical stimuli was preceded by four reminder trials with the original stimuli. This improved accuracy for all groups, but it was found that animals with PS lesions, not animals with T2/3 lesions, were impaired on between-category judgements. The impairment was not secondary to a disruption of basic visual sensory processing or significantly larger lesions relative to the Te2/3 group. As is the case for monkeys, accuracy with within-category stimuli was inferior to between-category stimuli for all groups. Possible reasons for this inter-species difference are discussed.

ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

We measured brain potentials from human subjects performing a mental rotation task requiring right-left judgments of misoriented hands, and a control task requiring palm-back judgments of the same stimuli. High-density, 128-channel event-related potentials (ERPs) were recorded from 16 normal, right-handed subjects. There was a main effect of task at five different latencies: 148 ms (occipital), 180 ms (parietal), 388 ms (vertex), 556 ms (central-parietal), and 900 ms (vertex). Source estimations derived from topographic data indicate that frontal brain regions were strongly activated after 300 ms in the control task, but not until about 900 ms in the rotation task. We conclude that the neural computations underlying mental hand rotation may be recruited from relatively early stages of visuo-perceptual analysis; these early computations influence subsequent processing within a parietal-prefrontal system for the integration of perception with action.

ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Limb denervation leads to reorganization of the representational zones of the somatosensory cortex. Using [11C](R)-PK11195, a sensitivein vivomarker of glial cell activation, and PET, we provide first evidence that limb denervation induces a trans-synaptic increase in [11C](R)-PK11195 binding in the human thalamus but not somatosensory cortex: these brain structures appeared morphologically normal on magnetic resonance imaging (MRI). The increased thalamic signal was detectable many years after nerve injury, indicating persistent reorganization of the thalamus. This glial activation, beyond the first-order projection area of the injured neurons, may reflect continually altered afferent activity. Our findings support the view that long-term rearrangement of cortical representational maps is significantly determined within the thalamus.

ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Differentiation and survival of sensory neurons is regulated by factors such as NGF and LIF. Regulation of signal transduction pathways downstream of such factor signalling by suppressor of cytokine signalling (SOCS) proteins, which negatively regulate the JAK/STAT pathway, may modulate biological outcome. In this study, SOCS1 regulation of growth factor mediated sensory neuron survival was examined. SOCS1 expression by sensory neurons was up-regulated by IFNγ. Survival of sensory neurons from SOCS1 null mice in NGF or LIF was similar to wildtype mice. IFNγ partially supported survival of wildtype neurons but supported survival of SOCS1 null neurons as effectively as NGF or LIF. Thus it appears that SOCS1 is a major regulator of sensory neuron responses to the inflammatory cytokine, IFNγ.

ISSN:0959-4965    

出版商:OVID    

年代:2001

数据来源: OVID