@article{376, abstract = {The compositional versatility of I2–II–IV–VI4 tetrahedrally-coordinated compounds allows for accommodating their functional properties to numerous technological applications. Among them, Cu2ZnSnSe4 is an emerging photovoltaic material and Cu2CdSnSe4 displays excellent thermoelectric properties. The third compound of this family, Cu2HgSnSe4, remains relatively unexplored. Herein, a synthetic route to produce Cu2HgSnSe4 nanoparticles with narrow size distribution and controlled composition is presented. Cu2HgSnSe4 nanoparticles were subsequently used as building blocks to produce bulk nanocrystalline materials, whose thermoelectric properties were analyzed. A very preliminary adjustment of the material composition yielded Seebeck coefficients up to 160 μV K−1, electrical conductivities close to 104 S m−1 and thermal conductivities down to 0.5 W m−1 K−1.}, author = {Li, Wenhua and Ibáñez, Maria and Zamani, Reza and García Castelló, Nuria and Stéphane, Grosse and Cadavid, Doris and Prades, Joan and Arbiol, Jordi and Cabot, Andreu}, journal = {CrystEngComm}, pages = {8966 -- 8971}, publisher = {Royal Society of Chemistry}, title = {{Cu2HgSnSe4 nanoparticles: synthesis and thermoelectric properties}}, doi = {10.1039/C3CE41583J}, volume = {44}, year = {2013}, } @article{378, abstract = {Until recently, to prepare nanocrystals of a new material, scientists searched their shelves for the appropriate molecular precursors, surfactants, and solvents. They then optimized the reaction conditions for the atoms to self-assemble into monodisperse nanocrystals (1). This approach is being replaced by a simpler strategy, in which preformed nanocrystals serve as templates to produce nanoparticles with a different composition through chemical transformation. On page 964 of this issue, Oh et al. (2) report a powerful mechanism that allows the composition of oxide nanoparticles to be transformed in solution and at low temperatures.}, author = {Ibáñez, Maria and Cabot, Andreu}, journal = {Science}, number = {6135}, pages = {935 -- 936}, publisher = {American Association for the Advancement of Science}, title = {{All change for nanocrystals}}, doi = {10.1126/science.1239221}, volume = {340}, year = {2013}, } @article{450, abstract = {Understanding the relative importance of heterosis and outbreeding depression over multiple generations is a key question in evolutionary biology and is essential for identifying appropriate genetic sources for population and ecosystem restoration. Here we use 2455 experimental crosses between 12 population pairs of the rare perennial plant Rutidosis leptorrhynchoides (Asteraceae) to investigate the multi-generational (F1, F2, F3) fitness outcomes of inter-population hybridization. We detected no evidence of outbreeding depression, with inter-population hybrids and backcrosses showing either similar fitness or significant heterosis for fitness components across the three generations. Variation in heterosis among population pairs was best explained by characteristics of the foreign source or home population, and was greatest when the source population was large, with high genetic diversity and low inbreeding, and the home population was small and inbred. Our results indicate that the primary consideration for maximizing progeny fitness following population augmentation or restoration is the use of seed from large, genetically diverse populations.}, author = {Pickup, Melinda and Field, David and Rowell, David and Young, Andrew}, journal = {Proceedings of the Royal Society of London Series B Biological Sciences}, number = {1750}, publisher = {Royal Society, The}, title = {{Source population characteristics affect heterosis following genetic rescue of fragmented plant populations}}, doi = {10.1098/rspb.2012.2058}, volume = {280}, year = {2013}, } @article{2438, abstract = {The colored Tverberg theorem asserts that for eve;ry d and r there exists t=t(d,r) such that for every set C ⊂ ℝ d of cardinality (d + 1)t, partitioned into t-point subsets C 1, C 2,...,C d+1 (which we think of as color classes; e. g., the points of C 1 are red, the points of C 2 blue, etc.), there exist r disjoint sets R 1, R 2,...,R r⊆C that are rainbow, meaning that {pipe}R i∩C j{pipe}≤1 for every i,j, and whose convex hulls all have a common point. All known proofs of this theorem are topological. We present a geometric version of a recent beautiful proof by Blagojević, Matschke, and Ziegler, avoiding a direct use of topological methods. The purpose of this de-topologization is to make the proof more concrete and intuitive, and accessible to a wider audience.}, author = {Matoušek, Jiří and Martin Tancer and Uli Wagner}, journal = {Discrete & Computational Geometry}, number = {2}, pages = {245 -- 265}, publisher = {Springer}, title = {{A geometric proof of the colored Tverberg theorem}}, doi = {10.1007/s00454-011-9368-2}, volume = {47}, year = {2012}, } @article{2439, abstract = {A Monte Carlo approximation algorithm for the Tukey depth problem in high dimensions is introduced. The algorithm is a generalization of an algorithm presented by Rousseeuw and Struyf (1998) . The performance of this algorithm is studied both analytically and experimentally.}, author = {Chen, Dan and Morin, Pat and Uli Wagner}, journal = {Computational Geometry: Theory and Applications}, number = {5}, pages = {566 -- 573}, publisher = {Elsevier}, title = {{Absolute approximation of Tukey depth: Theory and experiments}}, doi = {10.1016/j.comgeo.2012.03.001}, volume = {46}, year = {2012}, } @article{244, abstract = {We investigate the solubility of the congruence xy ≡ 1 (mod p), where p is a prime and x, y are restricted to lie in suitable short intervals. Our work relies on a mean value theorem for incomplete Kloosterman sums.}, author = {Timothy Browning and Haynes, Alan K}, journal = {International Journal of Number Theory}, number = {2}, pages = {481 -- 486}, publisher = {World Scientific Publishing}, title = {{Incomplete kloosterman sums and multiplicative inverses in short intervals}}, doi = { https://doi.org/10.1142/S1793042112501448}, volume = {9}, year = {2012}, } @inproceedings{2440, abstract = {We present an algorithm for computing [X, Y], i.e., all homotopy classes of continuous maps X → Y, where X, Y are topological spaces given as finite simplicial complexes, Y is (d - 1)-connected for some d ≥ 2 (for example, Y can be the d-dimensional sphere S d), and dim X ≤ 2d - 2. These conditions on X, Y guarantee that [X, Y] has a natural structure of a finitely generated Abelian group, and the algorithm finds generators and relations for it. We combine several tools and ideas from homotopy theory (such as Postnikov systems, simplicial sets, and obstruction theory) with algorithmic tools from effective algebraic topology (objects with effective homology). We hope that a further extension of the methods developed here will yield an algorithm for computing, in some cases of interest, the ℤ 2-index, which is a quantity playing a prominent role in Borsuk-Ulam style applications of topology in combinatorics and geometry, e.g., in topological lower bounds for the chromatic number of a graph. In a certain range of dimensions, deciding the embeddability of a simplicial complex into ℝ d also amounts to a ℤ 2-index computation. This is the main motivation of our work. We believe that investigating the computational complexity of questions in homotopy theory and similar areas presents a fascinating research area, and we hope that our work may help bridge the cultural gap between algebraic topology and theoretical computer science.}, author = {Čadek, Martin and Marek Krcál and Matoušek, Jiří and Sergeraert, Francis and Vokřínek, Lukáš and Uli Wagner}, pages = {1 -- 10}, publisher = {SIAM}, title = {{Computing all maps into a sphere}}, year = {2012}, } @inproceedings{2441, abstract = {Eigenvalues associated to graphs are a well-studied subject. In particular the spectra of the adjacency matrix and of the Laplacian of random graphs G(n, p) are known quite precisely. We consider generalizations of these matrices to simplicial complexes of higher dimensions and study their eigenvalues for the Linial-Meshulam model X k(n, p) of random k-dimensional simplicial complexes on n vertices. We show that for p = Ω(log n/n), the eigenvalues of both, the higher-dimensional adjacency matrix and the Laplacian, are a.a.s. sharply concentrated around two values. In a second part of the paper, we discuss a possible higherdimensional analogue of the Discrete Cheeger Inequality. This fundamental inequality expresses a close relationship between the eigenvalues of a graph and its combinatorial expansion properties; in particular, spectral expansion (a large eigenvalue gap) implies edge expansion. Recently, a higher-dimensional analogue of edge expansion for simplicial complexes was introduced by Gromov, and independently by Linial, Meshulam and Wallach and by Newman and Rabinovich. It is natural to ask whether there is a higher-dimensional version of Cheeger's inequality. We show that the most straightforward version of a higher-dimensional Cheeger inequality fails: for every k > 1, there is an infinite family of k-dimensional complexes that are spectrally expanding (there is a large eigenvalue gap for the Laplacian) but not combinatorially expanding.}, author = {Gundert, Anna and Uli Wagner}, pages = {151 -- 160}, publisher = {ACM}, title = {{On Laplacians of random complexes}}, doi = {10.1145/2261250.2261272}, year = {2012}, } @article{2453, abstract = {Constitutive endocytic recycling is a crucial mechanism allowing regulation of the activity of proteins at the plasma membrane and for rapid changes in their localization, as demonstrated in plants for PIN-FORMED (PIN) proteins, the auxin transporters. To identify novel molecular components of endocytic recycling, mainly exocytosis, we designed a PIN1-green fluorescent protein fluorescence imaging-based forward genetic screen for Arabidopsis thaliana mutants that showed increased intracellular accumulation of cargos in response to the trafficking inhibitor brefeldin A (BFA). We identified bex5 (for BFA-visualized exocytic trafficking defective), a novel dominant mutant carrying a missense mutation that disrupts a conserved sequence motif of the small GTPase, RAS GENES FROM RAT BRAINA1b. bex5 displays defects such as enhanced protein accumulation in abnormal BFA compartments, aberrant endosomes, and defective exocytosis and transcytosis. BEX5/RabA1b localizes to trans-Golgi network/early endosomes (TGN/EE) and acts on distinct trafficking processes like those regulated by GTP exchange factors on ADP-ribosylation factors GNOM-LIKE1 and HOPM INTERACTOR7/BFA-VISUALIZED ENDOCYTIC TRAFFICKING DEFECTIVE1, which regulate trafficking at the Golgi apparatus and TGN/EE, respectively. All together, this study identifies Arabidopsis BEX5/RabA1b as a novel regulator of protein trafficking from a TGN/EE compartment to the plasma membrane.}, author = {Feraru, Elena and Feraru, Mugurel Ioan and Asaoka, Rin and Paciorek, Tomasz and De Rycke, Riet M and Tanaka, Hirokazu and Nakano, Akihiko and Jirí Friml}, journal = {Plant Cell}, number = {7}, pages = {3074 -- 3086}, publisher = {American Society of Plant Biologists}, title = {{BEX5/RabA1b regulates trans-Golgi network-to-plasma membrane protein trafficking in Arabidopsis}}, doi = {10.1105/tpc.112.098152}, volume = {24}, year = {2012}, } @article{2456, abstract = {The third EMBO Conference on Plant Molecular Biology, which focused on ‘Plant development and environmental interactions’,was held in May 2012 in Matera, Italy. Here, we review some of the topics and themes that emerged from the various contributions; namely, steering technologies, transcriptional networks and hormonal regulation, small RNAs, cell and tissue polarity, environmental control and natural variation. We intend to provide the reader who might have missed this remarkable event with a glimpse of the recent progress made in this blossoming research field.}, author = {Beeckman, Tom and Friml, Jirí}, journal = {Development}, number = {20}, pages = {3677 -- 3682}, publisher = {Company of Biologists}, title = {{Plant developmental biologists meet on stairways in Matera}}, doi = {10.1242/dev.080861}, volume = {139}, year = {2012}, } @article{2458, abstract = {Initiation and successive development of organs induce mechanical stresses at the cellular level. Using the tomato shoot apex, a new study now proposes that mechanical strain regulates the plasma membrane abundance of the PIN1 auxin transporter, thereby reinforcing a positive feed-back loop between growth and auxin accumulation.}, author = {Li, Hongjiang and Friml, Jirí and Grunewald, Wim}, journal = {Current Biology}, number = {16}, pages = {R635 -- R637}, publisher = {Cell Press}, title = {{Cell polarity: Stretching prevents developmental cramps}}, doi = {10.1016/j.cub.2012.06.053}, volume = {22}, year = {2012}, } @article{2459, abstract = {Coordinated, subcellular trafficking of proteins is one of the fundamental properties of the multicellular eukaryotic organisms. Trafficking involves a large diversity of compartments, pathways, cargo molecules, and vesicle-sorting events. It is also crucial in regulating the localization and, thus, the activity of various proteins, but the process is still poorly genetically defined in plants. In the past, forward genetics screens had been used to determine the function of genes by searching for a specific morphological phenotype in the organism population in which mutations had been induced chemically or by irradiation. Unfortunately, these straightforward genetic screens turned out to be limited in identifying new regulators of intracellular protein transport, because mutations affecting essential trafficking pathways often lead to lethality. In addition, the use of these approaches has been restricted by functional redundancy among trafficking regulators. Screens for mutants that rely on the observation of changes in the cellular localization or dynamics of fluorescent subcellular markers enable, at least partially, to circumvent these issues. Hence, such image-based screens provide the possibility to identify either alleles with weak effects or components of the subcellular trafficking machinery that have no strong impact on the plant growth.}, author = {Zwiewka, Marta and Friml, Jirí}, journal = {Frontiers in Plant Science}, number = {May}, publisher = {Frontiers Research Foundation}, title = {{Fluorescence imaging-based forward genetic screens to identify trafficking regulators in plants}}, doi = {10.3389/fpls.2012.00097}, volume = {3}, year = {2012}, } @article{2474, abstract = {Interneurons are critical for neuronal circuit function, but how their dendritic morphologies and membrane properties influence information flow within neuronal circuits is largely unknown. We studied the spatiotemporal profile of synaptic integration and short-term plasticity in dendrites of mature cerebellar stellate cells by combining two-photon guided electrical stimulation, glutamate uncaging, electron microscopy, and modeling. Synaptic activation within thin (0.4 μm) dendrites produced somatic responses that became smaller and slower with increasing distance from the soma, sublinear subthreshold input-output relationships, and a somatodendritic gradient of short-term plasticity. Unlike most studies showing that neurons employ active dendritic mechanisms, we found that passive cable properties of thin dendrites determine the sublinear integration and plasticity gradient, which both result from large dendritic depolarizations that reduce synaptic driving force. These integrative properties allow stellate cells to act as spatiotemporal filters of synaptic input patterns, thereby biasing their output in favor of sparse presynaptic activity. Stellate cells are critical sources of inhibition in the cerebellum, but how their dendrites integrate excitatory synaptic inputs is unknown. Abrahamsson et al. show that thin dendrites and passive membrane properties of SCs promote sublinear synaptic summation and distance-dependent short-term plasticity. }, author = {Abrahamsson, Therese and Cathala, Laurence and Matsui, Ko and Ryuichi Shigemoto and DiGregorio, David A}, journal = {Neuron}, number = {6}, pages = {1159 -- 1172}, publisher = {Elsevier}, title = {{Thin dendrites of cerebellar interneurons confer sublinear synaptic integration and a gradient of short-term plasticity}}, doi = {10.1016/j.neuron.2012.01.027}, volume = {73}, year = {2012}, } @article{2475, abstract = {Background: One of the best-characterized causative factors of Alzheimer's disease (AD) is the generation of amyloid-β peptide (Aβ). AD subjects are at high risk of epileptic seizures accompanied by aberrant neuronal excitability, which in itself enhances Aβ generation. However, the molecular linkage between epileptic seizures and Aβ generation in AD remains unclear. Results: X11 and X11-like (X11L) gene knockout mice suffered from epileptic seizures, along with a malfunction of hyperpolarization-activated cyclic nucleotide gated (HCN) channels. Genetic ablation of HCN1 in mice and HCN1 channel blockage in cultured Neuro2a (N2a) cells enhanced Aβ generation. Interestingly, HCN1 levels dramatically decreased in the temporal lobe of cynomolgus monkeys (Macaca fascicularis) during aging and were significantly diminished in the temporal lobe of sporadic AD patients. Conclusion: Because HCN1 associates with amyloid-β precursor protein (APP) and X11/X11L in the brain, genetic deficiency of X11/X11L may induce aberrant HCN1 distribution along with epilepsy. Moreover, the reduction in HCN1 levels in aged primates may contribute to augmented Aβ generation. Taken together, HCN1 is proposed to play an important role in the molecular linkage between epileptic seizures and Aβ generation, and in the aggravation of sporadic AD.}, author = {Saito, Yuhki and Inoue, Tsuyoshi and Zhu, Gang and Kimura, Naoki and Okada, Motohiro and Nishimura, Masaki and Murayama, Shigeo and Kaneko, Sunao and Ryuichi Shigemoto and Imoto, Keiji and Suzuki, Toshiharu}, journal = {Molecular Neurodegeneration}, number = {1}, publisher = {BioMed Central}, title = {{Hyperpolarization-activated cyclic nucleotide gated channels: A potential molecular link between epileptic seizures and Aβ generation in Alzheimer's disease}}, doi = {10.1186/1750-1326-7-50}, volume = {7}, year = {2012}, } @article{2476, abstract = {Recently developed pharmacogenetic and optogenetic approaches, with their own advantages and disadvantages, have become indispensable tools in modern neuroscience. Here, we employed a previously described knock-in mouse line (GABA ARγ2 77Ilox) in which the γ2 subunit of the GABA A receptor (GABA AR) was mutated to become zolpidem insensitive (γ2 77I) and used viral vectors to swap γ2 77I with wild-type, zolpidem-sensitive γ2 subunits (γ2 77F). The verification of unaltered density and subcellular distribution of the virally introduced γ2 subunits requires their selective labelling. For this we generated six N- and six C-terminal-tagged γ2 subunits, with which cortical cultures of GABA ARγ2 -/- mice were transduced using lentiviruses. We found that the N-terminal AU1 tag resulted in excellent immunodetection and unimpaired synaptic localization. Unaltered kinetic properties of the AU1-tagged γ2 ( AU1γ2 77F) channels were demonstrated with whole-cell patch-clamp recordings of spontaneous IPSCs from cultured cells. Next, we carried out stereotaxic injections of lenti- and adeno-associated viruses containing Cre-recombinase and the AU1γ2 77F subunit (Cre-2A- AU1γ2 77F) into the neocortex of GABA ARγ2 77Ilox mice. Light microscopic immunofluorescence and electron microscopic freeze-fracture replica immunogold labelling demonstrated the efficient immunodetection of the AU1 tag and the normal enrichment of the AU1γ2 77F subunits in perisomatic GABAergic synapses. In line with this, miniature and action potential-evoked IPSCs whole-cell recorded from transduced cells had unaltered amplitudes, kinetics and restored zolpidem sensitivity. Our results obtained with a wide range of structural and functional verification methods reveal unaltered subcellular distributions and functional properties of γ2 77I and AU1γ2 77F GABA ARs in cortical pyramidal cells. This transgenic-viral pharmacogenetic approach has the advantage that it does not require any extrinsic protein that might endow some unforeseen alterations of the genetically modified cells. In addition, this virus-based approach opens up the possibility of modifying multiple cell types in distinct brain regions and performing alternative recombination-based intersectional genetic manipulations.}, author = {Sümegi, Máté and Fukazawa, Yugo and Matsui, Ko and Lörincz, Andrea and Eyre, Mark D and Nusser, Zoltán and Ryuichi Shigemoto}, journal = {Journal of Physiology}, number = {7}, pages = {1517 -- 1534}, publisher = {Wiley-Blackwell}, title = {{Virus-mediated swapping of zolpidem-insensitive with zolpidem-sensitive GABA A receptors in cortical pyramidal cells}}, doi = {10.1113/jphysiol.2012.227538}, volume = {590}, year = {2012}, } @article{2477, abstract = {Dynamic activity of glia has repeatedly been demonstrated, but if such activity is independent from neuronal activity, glia would not have any role in the information processing in the brain or in the generation of animal behavior. Evidence for neurons communicating with glia is solid, but the signaling pathway leading back from glial-to-neuronal activity was often difficult to study. Here, we introduced a transgenic mouse line in which channelrhodopsin-2, a light-gated cation channel, was expressed in astrocytes. Selective photostimulation of these astrocytes in vivo triggered neuronal activation. Using slice preparations, we show that glial photostimulation leads to release of glutamate, which was sufficient to activate AMPA receptors on Purkinje cells and to induce long-term depression of parallel fiber-to-Purkinje cell synapses through activation of metabotropic glutamate receptors. In contrast to neuronal synaptic vesicular release, glial activation likely causes preferential activation of extrasynaptic receptors that appose glial membrane. Finally, we show that neuronal activation by glial stimulation can lead to perturbation of cerebellar modulated motor behavior. These findings demonstrate that glia can modulate the tone of neuronal activity and behavior. This animal model is expected to be a potentially powerful approach to study the role of glia in brain function.}, author = {Sasaki, Takuya and Beppu, Kaoru and Tanaka, Kenji F and Fukazawa, Yugo and Ryuichi Shigemoto and Matsui, Ko}, journal = {PNAS}, number = {50}, pages = {20720 -- 20725}, publisher = {National Academy of Sciences}, title = {{Application of an optogenetic byway for perturbing neuronal activity via glial photostimulation}}, doi = {10.1073/pnas.1213458109}, volume = {109}, year = {2012}, } @article{2514, abstract = {Visual information must be relayed through the lateral geniculate nucleus before it reaches the visual cortex. However, not all spikes created in the retina lead to postsynaptic spikes and properties of the retinogeniculate synapse contribute to this filtering. To understand the mechanisms underlying this filtering process, we conducted electrophysiology to assess the properties of signal transmission in the Long-Evans rat. We also performed SDS-digested freeze-fracture replica labeling to quantify the receptor and transporter distribution, as well as EM reconstruction to describe the 3D structure. To analyze the impact of transmitter diffusion on the activity of the receptors, simulations were integrated. We identified that a large contributor to the filtering is the marked paired-pulse depression at this synapse, which was intensified by the morphological characteristics of the contacts. The broad presynaptic and postsynaptic contact area restricts transmitter diffusion two dimensionally. Additionally, the presence of multiple closely arranged release sites invites intersynaptic spillover, which causes desensitization of AMPA receptors. The presence of AMPA receptors that slowly recover from desensitization along with the high presynaptic release probability and multivesicular release at each synapse also contribute to the depression. These features contrast with many other synapses where spatiotemporal spread of transmitter is limited by rapid transmitter clearance allowing synapses to operate more independently. We propose that the micrometer-order structure can ultimately affect the visual information processing.}, author = {Budisantoso, Timotheus and Matsui, Ko and Kamasawa, Naomi and Fukazawa, Yugo and Ryuichi Shigemoto}, journal = {Journal of Neuroscience}, number = {7}, pages = {2357 -- 2376}, publisher = {Society for Neuroscience}, title = {{Mechanisms underlying signal filtering at a multisynapse contact}}, doi = {10.1523/JNEUROSCI.5243-11.2012}, volume = {32}, year = {2012}, } @article{2515, abstract = {We investigated the temporal and spatial expression of SK2 in the developing mouse hippocampus using molecular and biochemical techniques, quantitative immunogold electron microscopy, and electrophysiology. The mRNA encoding SK2 was expressed in the developing and adult hippocampus. Western blotting and immunohistochemistry showed that SK2 protein increased with age. This was accompanied by a shift in subcellular localization. Early in development (P5), SK2 was predominantly localized to the endoplasmic reticulum in the pyramidal cell layer. But by P30 SK2 was almost exclusively expressed in the dendrites and spines. The level of SK2 at the postsynaptic density (PSD) also increased during development. In the adult, SK2 expression on the spine plasma membrane showed a proximal-to-distal gradient. Consistent with this redistribution and gradient of SK2, the selective SK channel blocker apamin increased evoked excitatory postsynaptic potentials (EPSPs) only in CA1 pyramidal neurons from mice older than P15. However, the effect of apamin on EPSPs was not different between synapses in proximal or distal stratum radiatum or stratum lacunosum-moleculare in adult. These results show a developmental increase and gradient in SK2-containing channel surface expression that underlie their influence on neurotransmission, and that may contribute to increased memory acquisition during early development.}, author = {Ballesteros-Merino, Carmen and Lin, Michael and Wu, Wendy W and Ferrándiz-Huertas, Clotilde and Cabañero, María José and Watanabe, Masahiko and Fukazawa, Yugo and Ryuichi Shigemoto and Maylie, James G and Adelman, John P and Luján, Rafael}, journal = {Hippocampus}, number = {6}, pages = {1467 -- 1480}, publisher = {Wiley-Blackwell}, title = {{ Developmental profile of SK2 channel expression and function in CA1 neurons}}, doi = {10.1002/hipo.20986}, volume = {22}, year = {2012}, } @article{2687, abstract = {Left-right asymmetry of human brain function has been known for a century, although much of molecular and cellular basis of brain laterality remains to be elusive. Recent studies suggest that hippocampal CA3-CA1 excitatory synapses are asymmetrically arranged, however, the functional implication of the asymmetrical circuitry has not been studied at the behavioral level. In order to address the left-right asymmetry of hippocampal function in behaving mice, we analyzed the performance of "split-brain" mice in the Barnes maze. The "split-brain" mice received ventral hippocampal commissure and corpus callosum transection in addition to deprivation of visual input from one eye. In such mice, the hippocampus in the side of visual deprivation receives sensory-driven input. Better spatial task performance was achieved by the mice which were forced to use the right hippocampus than those which were forced to use the left hippocampus. In two-choice spatial maze, forced usage of left hippocampus resulted in a comparable performance to the right counterpart, suggesting that both hippocampal hemispheres are capable of conducting spatial learning. Therefore, the results obtained from the Barnes maze suggest that the usage of the right hippocampus improves the accuracy of spatial memory. Performance of non-spatial yet hippocampus-dependent tasks (e.g. fear conditioning) was not influenced by the laterality of the hippocampus.}, author = {Shinohara, Yoshiaki and Hosoya, Aki and Yamasaki, Nobuyuki and Ahmed, Hassan and Hattori, Satoko and Eguchi, Megumi and Yamaguchi, Shun and Miyakawa, Tsuyoshi and Hirase, Hajime and Ryuichi Shigemoto}, journal = {Hippocampus}, number = {2}, pages = {117 -- 121}, publisher = {Wiley-Blackwell}, title = {{Right-hemispheric dominance of spatial memory in split-brain mice}}, doi = {10.1002/hipo.20886}, volume = {22}, year = {2012}, } @article{2688, abstract = {To gain insights into structure-function relationship of excitatory synapses, we revisit our quantitative analysis of synaptic AMPAR by highly sensitive freeze-fracture replica labeling in eight different connections. All of these connections showed linear correlation between synapse size and AMPAR number indicating a common intra-synapse-type relationship in CNS synapses. On the contrary, inter-synapse-type relationship is unexpected indicating no correlation between averages of synapse size and AMPAR number. Interestingly, connections with large average synapse size and low AMPAR density showed high variability of AMPAR number and mosaic distribution within the postsynaptic membrane. We propose an idea that these connections may quickly exhibit synaptic plasticity by modifying AMPAR density/number whereas those with high AMPAR density change their efficacy by modifying synapse size.}, author = {Fukazawa, Yugo and Ryuichi Shigemoto}, journal = {Current Opinion in Neurobiology}, number = {3}, pages = {446 -- 452}, publisher = {Elsevier}, title = {{Intra-synapse-type and inter-synapse-type relationships between synaptic size and AMPAR expression}}, doi = {10.1016/j.conb.2012.01.006}, volume = {22}, year = {2012}, }