摘要:

INSULIN-LIKE growth factor 1 (IGF-1) plays a critical role in CNS development. IGF-1 can block neuronal apoptosisin vitroandin vivo. IGF-1 is thought to be cleaved into des-N-(1-3)-IGF-1 and an amino terminal glycine-proline-glutamate (GPE tripeptide). Here we report a neuroprotective role for GPE tripeptide, with enhanced survival of the CA1-2 hippocampal neurons following an excitotoxic insultin vitro. Binding and displacement studies suggest uniquely distributed sites of action within the rat including the hippocampal CA1-2, pyriform cortex, amygdala, choroid plexus, blood vessels and to a lesser extent in the cortical regions. A similar pattern of binding was seen in the human. This finding could lead to new strategies to reduce neuronal death after injury and in disease.

ISSN:0959-4965    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

THE two main song control nuclei in the zebra finch forebrain, the higher vocal center (HVC) and the robust nucleus of the archistriatum (RA), receive cholinergic innervation from the ventral paleostriatum (VP) of the basal forebrain which may play a key role in song learning. By injecting two kinds of neuroanatomical tracers, we found that a topographically segregated pathway from nucleus ovoidalis (Ov) and nucleus dorsomedialis posterior thalami (DMP) to VP and further to RA and HVC. Ov is known as a major relay in the main ascending auditory pathway. The results suggest that cholinergic neurons in the VP which are responsible for song learning are regulated by auditory information from the Ov.

ISSN:0959-4965    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

IN the fishOreochromis mossambicus, light conditions affect the development of the roll-induced vestibuloocular reflex (rVOR). During development under continous light-dark conditions the rVOR amplitude, which is the maximum eye movement during a complete 360° lateral roll, shows a secondary drop after a first peak at stage 17 by 64% (36.3° at stage 17; 13.0° at stage 20). This drop was shifted by 2 stages to older postembryonal stages and was 33% (29.2° at stage 20; 19.5° at stage 22) less pronounced in animals which were exposed to complete darkness for several days. Because the period of rVOR diminution is sensitive to light conditions, it is likely that outgrowing visual projection fibres reorganize the neuronal network underlying visual-vestibular behavior thus transiently suppressing the rVOR.

ISSN:0959-4965    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ACTIVATION of the immune system has been associated with the development of fatigue of unknown cause. We were interested in brain energy stores (e.g., phosphocreatine (PCr) and creatine kinase) after immune activation to investigate whether this system was altered. In this model, fatigue (defined as > 50% reduction in spontaneous running) was induced in C57BL/6 mice after a single injection ofCorynebacterium parvumantigen. Maximal fatigue (about 86% reduction on day 10 post injection) was associated with reduced (about 29%) brain PCr/γ-ATP and increased creatine kinase levels (∼31%), suggesting anactive process of brain ATP depletion and replenishment. These findings need to be further delineated to establish the relationship between immune activation, reduced brain energy pools and fatigue.

ISSN:0959-4965    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

TO test whether the human fusiform face area (FFA) responds not only to faces but to anything human or animate, we used fMRI to measure the response of the FFA to six new stimulus categories. The strongest responses were to stimuli containing faces: human faces (2.0% signal increase from fixation baseline) and human heads (1.7%), with weaker but still strong responses to whole humans (1.5%) and animal heads (1.3%). Responses to whole animals (1.0%) and human bodies without heads (1.0%) were significantly stronger than responses to inanimate objects (0.7%), but responses to animal bodies without heads (0.8%) were not. These results demonstrate that the FFA is selective for faces, not for animals.

ISSN:0959-4965    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BEHAVIORAL and neuropsychological studies suggest that upright and inverted face stimuli are processed by computationally and anatomically distinct systems. Specifically, inverted faces seem to be addressed by general object perception systems, avoiding face-specific processes. We tested this model by examining the fMRI signal response of a functionally defined fusiform face area and bilateral object-responsive cortical areas during the perception of upright and inverted stimuli (faces and cars). While inversion of face stimuli had no effect upon the magnitude of responses in the fusiform face area, inverted faces evoked greater neural responses compared to upright faces within object regions. This finding supports the assertion that object areas are involved to a greater degree in the perception of invertedvsupright faces.

ISSN:0959-4965    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

WE report two functional magnetic resonance imaging (fMRI) experiments which reveal a cortical network activated when perceiving coloured grids, and experiencing the McCollough effect (ME). Our results show that perception of red-black and green-black grids activate the right fusiform gyrus (area V4) plus the left and right lingual gyri, right striate cortex (V1) and left insula. The ME activated the left anterior fusiform gyrus as well as the ventrolateral prefrontal cortex, and in common with colour perception, the left insula. These data confirm the critical role of the fusiform gyrus in actual and illusory colour perception as well as revealing localized frontal cortical activation associated with the ME, which would suggest that a ‘top-down’ mechanism is implicated in this illusion.

ISSN:0959-4965    

出版商:OVID    

年代:1999

数据来源: OVID