44 research outputs found

    Heating-free, room-temperature operation of a radiofrequency-to-light signal transducer with a membrane oscillator and a built-in metasurface mirror

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    We present an electro-mechano-optical radiofrequency (rf)-to-light signal transducer robust against laser heating and thus operational at room temperature. A metal-free, low-loss metasurface mirror and an aluminum electrode made separately on a Si₃N₄ membrane oscillator comprise a chain of electro-mechanical and opto-mechanical systems, mediating electrical and optical signals through the (2, 2)-mode characteristic oscillation. We demonstrate up-conversion of rf signals at 175.2 MHz by 6 orders of magnitude in frequency to an optical regime with the transfer efficiency of 2.3 × 10⁻⁹, also showing stable operation due to reduced laser heating of the mirror

    Enriched Expression of Serotonin 1B and 2A Receptor Genes in Macaque Visual Cortex and their Bidirectional Modulatory Effects on Neuronal Responses

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    To study the molecular mechanism how cortical areas are specialized in adult primates, we searched for area-specific genes in macaque monkeys and found striking enrichment of serotonin (5-hydroxytryptamine, 5-HT) 1B receptor mRNA, and to a lesser extent, of 5-HT2A receptor mRNA, in the primary visual area (V1). In situ hybridization analyses revealed that both mRNA species were highly concentrated in the geniculorecipient layers IVA and IVC, where they were coexpressed in the same neurons. Monocular inactivation by tetrodotoxin injection resulted in a strong and rapid (<3 h) downregulation of these mRNAs, suggesting the retinal activity dependency of their expression. Consistent with the high expression level in V1, clear modulatory effects of 5-HT1B and 5-HT2A receptor agonists on the responses of V1 neurons were observed in in vivo electrophysiological experiments. The modulatory effect of the 5-HT1B agonist was dependent on the firing rate of the recorded neurons: The effect tended to be facilitative for neurons with a high firing rate, and suppressive for those with a low firing rate. The 5-HT2A agonist showed opposite effects. These results suggest that this serotonergic system controls the visual response in V1 for optimization of information processing toward the incoming visual inputs

    Paraneoplastic Antigen-Like 5 Gene (PNMA5) Is Preferentially Expressed in the Association Areas in a Primate Specific Manner

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    To understand the relationship between the structure and function of primate neocortical areas at a molecular level, we have been screening for genes differentially expressed across macaque neocortical areas by restriction landmark cDNA scanning (RLCS). Here, we report enriched expression of the paraneoplastic antigen-like 5 gene (PNMA5) in association areas but not in primary sensory areas, with the lowest expression level in primary visual cortex. In situ hybridization in the primary sensory areas revealed PNMA5 mRNA expression restricted to layer II. Along the ventral visual pathway, the expression gradually increased in the excitatory neurons from the primary to higher visual areas. This differential expression pattern was very similar to that of retinol-binding protein (RBP) mRNA, another association-area-enriched gene that we reported previously. Additional expression analysis for comparison of other genes in the PNMA gene family, PNMA1, PNMA2, PNMA3, and MOAP1 (PNMA4), showed that they were widely expressed across areas and layers but without the differentiated pattern of PNMA5. In mouse brains, PNMA1 was only faintly expressed and PNMA5 was not detected. Sequence analysis showed divergence of PNMA5 sequences among mammals. These findings suggest that PNMA5 acquired a certain specialized role in the association areas of the neocortex during primate evolution

    宇宙空間からの観測による中間圏および下部熱圏における可視近赤外域大気光の構造についての研究

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    京都大学0048新制・課程博士博士(理学)甲第18798号理博第4056号新制||理||1583(附属図書館)31749京都大学大学院理学研究科地球惑星科学専攻(主査)准教授 齊藤 昭則, 教授 田口 聡, 教授 余田 成男学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA

    Prefrontal-Enriched SLIT1 Expression in Old World Monkey Cortex Established during the Postnatal Development

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    To elucidate the molecular basis of the specialization of cortical architectures, we searched for genes differentially expressed among neocortical areas of Old World monkeys by restriction landmark cDNA scanning. We found that mRNA of SLIT1, an axon guidance molecule, was enriched in the prefrontal cortex but with developmentally related changes. In situ hybridization analysis revealed that SLIT1 mRNA was mainly distributed in the middle layers of most cortical areas, robustly in the prefrontal cortex and faintly in primary sensory areas. The lowest expression was in the primary visual area. Analyses of other SLIT (SLIT2 and SLIT3) mRNAs showed preferential expression in the prefrontal cortex with a distinct laminar pattern. By contrast, the receptor Roundabout (ROBO1 and ROBO2) mRNAs were widely distributed throughout the cortex. Perinatally, SLIT1 mRNA was abundantly expressed in the cortex with modest area specificity. Downregulatio
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