MT neurons in the macaque exhibited two types of bimodal direction tuning as predicted by a model for visual motion detection

AbstractWe previously proposed a model for detecting local image velocity on the magnocellular visual pathway (Kawakami & Okamoto (1996) Vision Research, 36, 117–147). The model detects visual motion in two stages using the hierarchical network that includes component and pattern cells in area MT. To validate the model, we predicted two types of bimodal direction tuning for MT neurons. The first type is characteristic of component cells. The tuning is bimodal when stimulated with high-speed spots, but unimodal for low-speed spots or for bars. The interval between the two peaks widens as the spot’s speed increases. The second type is characteristic of pattern cells. The tuning is bimodal when stimulated with low-speed bars, but unimodal for high-speed bars or for spots. The interval widens as the bar’s speed decreases. To confirm this prediction, we studied the change of direction tuning curves for moving spots and bars in area MT of macaque monkeys. Out of 35 neurons measured at various speeds, six component cells and four pattern cells revealed the predicted bimodal tunings. This result provided neurophysiological support for the validity of the model. We believe ours is the first systematic study that records the two types of bimodality in MT neurons

Distribution and life histories of tiger beetles (Coleoptera: Cicindelidae) in Tottori Sand Dunes (Tottori City, Honshu, Japan) with remarks on the extinction of Calomera angulata.

2013年から2014年にかけて鳥取砂丘の全域でハンミョウ類の生息調査をおこない，カワラハンミョウの幼虫の巣穴が砂丘のほぼ全域にみられるのに対し，エリザハンミョウのそれはオアシス周辺の湿り気のある砂泥地表に限定されていることを確認した。1990年代までオアシス周辺で生息が確認されていたハラビロハンミョウは確認できず，鳥取砂丘からは絶滅したと判断される。当地は環境省国立公園の特別保護地区であり，採集は厳密に規制されているのでこの絶滅は1994年からはじまった除草に影響された可能性が強く疑われる。本種の鳥取砂丘内での最終確認は1997年である。カワラハンミョウとエリザハンミョウについてはコドラート調査により，カワラハンミョウは基本的に年1化で1 ～ 2齢の幼虫で越冬，エリザハンミョウも年1化だがすべての齢で越冬していると推定された。巣穴は1年をとおして集中分布でとくに若齢幼虫の多い秋季にはその傾向がめだった。We surveyed distributions and life histories of cicindelid beetles in Tottori Sand Dunes, Tottori Prefecture, Honshu, Japan. Larval nests of Chaetodera laetescripta were widely found in the bare arenaceous ground around vegetation of sandy shore plants in the dunes, while those of Cilindela elisae were limited to the bare silt-mingling arenaceous ground along the stream flowing into the pool called “Oasis”. No adults and nests of Calomera angulata (Fabricius, 1798) that had been found up to 1990s around “Oasis”were found. Absence of the records of Calomera angulata from Tottori Sand Dunes after the last observation in 1997 strongly suggests extinction of the species in the area. It is highly suggested that weeding activities that started in 1994 in Tottori Sand Dunes influenced negatively for the occurrence of the species, because Tottori Sand Dunes has been designated as a special protection area of the national parks by the Japan Ministry of Environment and collecting animals and plants and other activities that may influence conservation of the environment are strictly regulated. Chaetodera laetescripta and Cilindela elisae were univoltine and adults appeared from July. Analyses of dispersion pattern of larval nests for the two species showed contagious distribution

In vivo target exploration of apidaecin based on Acquired Resistance induced by Gene Overexpression (ARGO assay)

Identifying the target molecules of antimicrobial agents is essential for assessing their mode of action. Here, we propose Acquired Resistance induced by Gene Overexpression (ARGO) as a novel in vivo approach for exploring target proteins of antimicrobial agents. The principle of the method is based on the fact that overexpression of the expected target protein leads to reduced sensitivity to the antimicrobial agent. We applied this approach to identify target proteins of the antimicrobial peptide apidaecin, which is specifically effective against Gram-negative bacteria. To this end, a set of overexpression Escherichia coli clones was tested, and peptide chain release factor 1, which directs the termination of translation, was found as a candidate, suggesting that apidaecin inhibits the termination step of translation. This finding was confirmed in vivo and in vitro by evaluating the inhibitory activity of apidaecin towards lacZ reporter gene expression, which is tightly dependent on its stop codon. The results of this study demonstrate that apidaecin exerts its antimicrobial effects partly by inhibiting release factors

A Survey of Changes in the Psychological State of Individuals with Social Withdrawal (<i>hikikomori</i>) in the Context of the COVID Pandemic

Background: The coronavirus disease (COVID) 2019 pandemic has been reported to have resulted in psychological disturbances. The Japanese term “hikikomori” refers to a state of preferring to stay at home. The COVID pandemic provided an opportunity to extend our current understanding of hikikomori by examining the psychological states of individuals who were in this state under lockdown, during which, paradoxically, their condition may have been adaptive. Methods: We administered a questionnaire to examine psychological changes among 600 people with hikikomori traits in Japan. The Hospital Anxiety and Depression Scale (HADS), Subjective Stress Scale, and Stigma Questions for hikikomori were administered retrospectively at three time points. We also collected descriptive data regarding the participants’ coping strategies. Results: The participants’ sense of stigma regarding hikikomori was improved during the pandemic, whereas depression and anxiety worsened. The participants with ‘definite’ hikikomori (they met the diagnostic criteria) reported more severe depression and anxiety than those with ‘possible’ hikikomori. Their coping strategies were adaptive to the pandemic situation. Conclusion: Although the sense of stigma against hikikomori was improved and adaptive strategies were employed, the participants with hikikomori experienced a worsening of depression and anxiety during the COVID lockdowns. The improvement of stigma and the participants’ indoor adaptive coping strategies could not ameliorate the mental state of hikikomori. Therapeutic interventions should be considered in the future for definite hikikomori meeting the criteria

Self-Assembling Polymer Micelle/Clay Nanodisk/Doxorubicin Hybrid Injectable Gels for Safe and Efficient Focal Treatment of Cancer

The purpose of this study was to fabricate a safe and effective doxorubicin (DOX)-delivery system for focal cancer chemotherapy. A novel biodegradable injectable gel was developed through self-assembly of poly­(d,l-lactide-<i>co</i>-glycolide)-<i>b</i>-poly­(ethylene glycol)-<i>b</i>-poly­(d,l-lactide-<i>co</i>-glycolide) (PLGA-PEG-PLGA) copolymer micelles, clay nanodisks (CNDs), and DOX. We discovered that DOX loaded in the hybrid gels acts as an anticancer drug and as a building block to organize new gel networks. Accordingly, long-term sustained release of DOX from hybrid injectable gels without initial burst release was achieved. Moreover, it was revealed that the DOX incorporated into gel networks controls its own release profile. This hybrid injectable gel is a self-controlled drug release system, which is a novel concept in controlled drug release. Importantly, a single injection of PLGA-PEG-PLGA/CND/DOX hybrid gel provides long-term sustained antitumor activity in vivo against human xenograft tumors in mice, suggesting the potential of hybrid gels as a valuable local DOX-delivery platform for cancer focal therapy

Dirac semimetal phase and switching of band inversion in XMg₂Bi₂ (X = Ba and Sr)

角度分解光電子分光と第一原理バンド計算とを組み合わせることで、三元化合物BaMg₂Bi₂が、結晶のC3対称性によって保護されたブリルアンゾーン中心付近で交差する単純なディラックバンドを持つトポロジカルディラック半金属であることを明らかにした。また、同じ結晶構造を持つSrMg₂Bi₂は、スピン−軌道相互作用の減少によりバンド反転がないことを特徴とする通常の絶縁体となっていることがわかった