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排序方式: 共有1933条查询结果,搜索用时 15 毫秒
111.
This article reports an investigation on light-addressable potentiometric sensor (LAPS) to be used as a possible biological cell-semiconductor hybrid that will enable us to make an interface between the physical and biological system. To increase the surface potential sensitivity, we used a LAPS structure with single insulator (SiO2) coated with poly-L-ornithine and laminin (PLOL) on Si. Efficient culturing of PC-12 and nerve cells of Lymnaea stagnalis on PLOL-coated Si3N4 and SiO2 was achieved. The thickness of the PLOL layer was found to be about 4 nm by the atomic force microscope (AFM) measurement. Using the advantage of this thin layer of PLOL, we compared the performance of a novel structure to the previously reported "PLOL-coated Si3N4/SiO2/Si" structure. Due to high insulating capacitance, the photocurrent response of the novel LAPS was found to be very steep. As a result, higher sensitivity was achieved. This steepness did not degrade during 10 days when the sensor surface was kept in contact with the cell culture medium and environment. The thickness of PLOL layer, its ability to improve the biological cell adhesion, enhanced sensitivity, and experiment with simulated neural action potential (AP) applied to the novel LAPS show a good promise for LAPS to be a biological cell-semiconductor hybrid.  相似文献   
112.
Neural cell adhesion molecules (NCAMs) play critical roles during development of the nervous system. The aim of this study is to investigate the possible effect of ethanol exposure on the pattern of expression and sialylation of NCAM isoforms during postnatal rat brain development because alterations in NCAM content and distribution have been associated with defects in cell migration, synapse formation, and memory consolidation, and deficits in these processes have been observed after in utero alcohol exposure. The expression of NCAM isoforms in the developing cerebral cortex of pups from control and alcohol-fed mothers was assessed by western blotting, ribonuclease protection assay, and immunocytochemistry. The highly sialylated form of NCAM [polysialic acid (PSA)-NCAM] is mainly expressed during the neonatal period and then is down-regulated in parallel with the appearance of NCAM 180 and NCAM 140. Ethanol exposure increases PSA-NCAM levels during the neonatal period, delays the loss of PSA-NCAM, decreases the amount of NCAM 180 and NCAM 140 isoforms, and reduces sialyltransferase activity during postnatal brain development. Neuraminidase treatment of ethanol-exposed neonatal brains leads to more intense band degradation products, suggesting a higher content of NCAM polypeptides carrying PSA in these samples. However, NCAM mRNA levels are not changed by ethanol. Immunocytochemical analysis demonstrates that ethanol triggers an increase in PSA-NCAM immunolabeling in the cytoplasm of astroglial cells, accompanied by a decrease in immunogold particles over the plasma membrane. These findings indicate that ethanol exposure during brain development alters the pattern of NCAM expression and suggest that modification of NCAM could affect neuronal-glial interactions that might contribute to the brain defects observed after in utero alcohol exposure.  相似文献   
113.
The neural cell adhesion molecule (NCAM) mediates cell adhesion and signal transduction through trans-homophilic- and/or cis-heterophilic-binding mechanisms. Intraventricular infusions of anti-NCAM have revealed a functional requirement of NCAM for the consolidation of memory in rats and chicks in a specific interval 6-8 h after training. We have now extended these studies to a synthetic peptide ligand of NCAM (C3) with an affinity for the IgI domain and the capability of inhibiting NCAM-mediated neurite outgrowth in vitro. Intraventricular administration of a single 5 microg bolus of C3 strongly inhibited recall of a passive avoidance response in adult rats, when given during training or in the 6-8-h posttraining period. The effect of C3 on memory consolidation was similar to that obtained with anti-NCAM as the amnesia was not observed until the 48-h recall time. The unique amnesic action of C3 during training could be related to disrupted NCAM internalization following training. In the 3-4-h posttraining period NCAM 180, the synapse-associated isoform, was down-regulated in the hippocampal dentate gyrus. This effect was mediated by ubiquitination and was prevented by C3 administration during training. These findings indicate NCAM to be involved in both the acquisition and consolidation of a passive avoidance response in the rat. Moreover, the study provides the first in vivo evidence for NCAM internalization in learning and identifies a synthetic NCAM ligand capable of modulating memory processes in vivo.  相似文献   
114.
115.
 The homeobox gene Carp-Ovx1 shows similarity to vertebrate and invertebrate Ovx genes and to Drosophila unplugged. Its expression pattern was studied by in situ hybridization in carp embryos and juveniles. During segmentation, expression becomes gradually limited to the neural tube. In juveniles up to 9 weeks old, cells in the ventral telencephalon, the facial lobe and the vagal lobe show Ovx1 expression, confining expression to parts with chemosensory projections. Received: 29 October 1997 / Accepted: 12 November 1997  相似文献   
116.
117.
鸟类呼吸与发声的神经调控   总被引:4,自引:2,他引:2  
鸟类的发声产生于呼吸过程的呼气相;呼吸与发声中枢控制通路间具有复杂的纤维联系,构成“发声通讯复合体”;前脑的RA是鸣禽协调呼吸与发声的高位中枢;脑干部的DM、nRAm、PBvl、IOS、RVL及Ⅻts等核团参与呼吸肌及鸣肌活动的调节,使呼吸与发声的配合准确、协调。  相似文献   
118.
Modern brain technology is a highly dynamic and innovative field of research with great potential for medical applications. Recent advances in recording neural signals from the brain by brain-machine interfacing presage new therapeutic options for paralyzed people by means of neural motor prostheses. This paper examines foreseeable ethical questions related to the research on brainmachine interfaces and their possible future applications. It identifies four major topics that need to be considered: first, the questions of personality and its possible alterations; second, responsibility and its possible constraints; third, therapeutic applications and their possible exceedance; and fourth, questions of research ethics that arise when progressing from animal experimentation to application to human subjects. This paper, in identifying and addressing the ethical questions raised by brain-machine interfaces, presents concerns that need to be considered if possible prosthetics based on modern brain technology are to be used cautiously and responsibly.  相似文献   
119.
During anoxia, overall protein synthesis is almost undetectable in the brain of the western painted turtle. The aim of this investigation was to address the question of whether there are alterations to specific proteins by comparing the normoxic and anoxic brain proteomes. Reductions in creatine kinase, hexokinase, glyceraldehyde‐3‐phosphate dehydrogenase, and pyruvate kinase reflected the reduced production of adenosine triphosphate (ATP) during anoxia while the reduction in transitional endoplasmic reticulum ATPase reflected the conservation of ATP or possibly a decrease in intracellular Ca2+. In terms of neural protection programed cell death 6 interacting protein (PDCD6IP; a protein associated with apoptosis), dihydropyrimidinase‐like protein, t‐complex protein, and guanine nucleotide protein G(o) subunit alpha (Go alpha; proteins associated with neural degradation and impaired cognitive function) also declined. A decline in actin, gelsolin, and PDCD6IP, together with an increase in tubulin, also provided evidence for the induction of a neurological repair response. Although these proteomic alterations show some similarities with the crucian carp (another anoxia‐tolerant species), there are species‐specific responses, which supports the theory of no single strategy for anoxia tolerance. These findings also suggest the anoxic turtle brain could be an etiological model for investigating mammalian hypoxic damage and clinical neurological disorders.  相似文献   
120.
Wang  Ziyin  Wang  Rubin  Fang  Ruiyan 《Cognitive neurodynamics》2015,9(2):129-144
This paper aimed at assessing and comparing the effects of the inhibitory neurons in the neural network on the neural energy distribution, and the network activities in the absence of the inhibitory neurons to understand the nature of neural energy distribution and neural energy coding. Stimulus, synchronous oscillation has significant difference between neural networks with and without inhibitory neurons, and this difference can be quantitatively evaluated by the characteristic energy distribution. In addition, the synchronous oscillation difference of the neural activity can be quantitatively described by change of the energy distribution if the network parameters are gradually adjusted. Compared with traditional method of correlation coefficient analysis, the quantitative indicators based on nervous energy distribution characteristics are more effective in reflecting the dynamic features of the neural network activities. Meanwhile, this neural coding method from a global perspective of neural activity effectively avoids the current defects of neural encoding and decoding theory and enormous difficulties encountered. Our studies have shown that neural energy coding is a new coding theory with high efficiency and great potential.  相似文献   
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