Seiichiro Sakai

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In recent years, optical stimulation of neurons that bear a light-gated cation channel, "Optogenetics", has opened a new avenue for exploring neuronal connectivity of the nervous system. In this study, we applied a technique, "Opto-fMRI", which combined optogenetics with blood oxygenation level-dependent (BOLD) functional MRI (fMRI), for examining the(More)
Channelrhodopsin-1 and 2 (ChR1 and ChR2) form cation channels that are gated by light through an unknown mechanism. We tested the DC-gate hypothesis that C167 and D195 are involved in the stabilization of the cation-permeable state of ChRWR/C1C2 which consists of TM1-5 of ChR1 and TM6-7 of ChR2 and ChRFR which consists of TM1-2 of ChR1 and TM3-7 of ChR2.(More)
Optical manipulation technologies greatly advanced the understanding of the neuronal network and its dysfunctions. To achieve patterned and parallel optical switching, we developed a microscopic illumination system using a commercial DMD-based projector and a software program. The spatiotemporal patterning of the system was evaluated using acute slices of(More)
Channelrhodopsin (ChR)-wide receiver (ChRWR), one of the chimeric molecule of ChR1 and ChR2, has several advantages over ChR2 such as improved expression in the plasma membrane and enhanced photocurrent with small desensitization. Here we generated transgenic zebrafish (Danio rerio) expressing ChRWR as a conjugate of EGFP under the regulation of UAS(More)
Optogenetic manipulation of the neuronal activity enables one to analyze the neuronal network both in vivo and in vitro with precise spatio-temporal resolution. Channelrhodopsins (ChRs) are light-sensitive cation channels that depolarize the cell membrane, whereas halorhodopsins and archaerhodopsins are light-sensitive Cl(-) and H(+) transporters,(More)
The mammalian neocortex contains many cell types, but whether they organize into repeated structures has been unclear. We discovered that major cell types in neocortical layer 5 form a lattice structure in many brain areas. Large-scale three-dimensional imaging revealed that distinct types of excitatory and inhibitory neurons form cell type-specific radial(More)
It is generally accepted that the extent of plasticity is localized to the region around synapses and post-synaptic intracellular signaling cascades. We investigated the presence of long-range retrograde plasticity associated with excitability at pre-synaptic neurons (CA3) and regulated by the firing of post-synaptic neurons (CA1). We used acute hippocampus(More)
Nobiletin isolated from citrus peels prevents bulbectomy- and amyloid-beta protein-induced memory impairment in rodents. In the present study, using combined methods of biochemistry and electrophysiology, we examined the effects of nobiletin on phosphorylation of GluR1 receptor, the subunit of alpha-amino-3-hydroxy-5-methyl-D-aspartate (AMPA) receptors, and(More)
Core fucosylation is catalyzed by α1,6-fucosyltransferase (FUT8), which transfers a fucose residue to the innermost GlcNAc residue via α1,6-linkage on N-glycans in mammals. We previously reported that Fut8-knock-out (Fut8(-/-)) mice showed a schizophrenia-like phenotype and a decrease in working memory. To understand the underlying molecular mechanism, we(More)
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