Sub-Millisecond Firing Synchrony of Closely Neighboring Pyramidal Neurons in Hippocampal CA1 of Rats During Delayed Non-Matching to Sample Task

Firing synchrony among neurons is thought to play functional roles in several brain regions. In theoretical analyses, firing synchrony among neurons within sub-millisecond precision is feasible to convey information. However, little is known about the occurrence and the functional significance of the sub-millisecond synchrony among closely neighboring neurons in the brain of behaving animals because of a technical issue: spikes simultaneously generated from closely neighboring neurons are overlapped in the extracellular space and are not easily separated. As described herein, using a unique spike sorting technique based on independent component analysis together with extracellular 12-channel multi-electrodes (dodecatrodes), we separated such overlapping spikes and investigated the firing synchrony among closely neighboring pyramidal neurons in the hippocampal CA1 of rats during a delayed non-matching to sample task. Results showed that closely neighboring pyramidal neurons in the hippocampal CA1 can co-fire with sub-millisecond precision. The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison) and external (stimulus input and motor output) events during the task. However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently. We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information – as represented by the firing rate modulations – to downstream neurons

諸種吸着相ニ因ル毒物吸着ノ生物學的研究

炭類ガ著明ナル吸着作用ヲ有スルコトハ甚ダ舊キ時代ヨリ知ラレタル事實ニシテ, 之レガ治療的應用ハ既ニ埃及時代ヨリ試ミラレタルガ如シ. 而シテ炭類ノ吸着作用ニ就テ, 科學的ニ藥物學的研究ヲ行ヒタルハWichowskiヲ以テ嚆矢トナス. 輓近丹村氏ハ血炭及ビ木炭ノ毒物吸着ニ關スル生物學的研究ヲ發表セリ. 余ハ摘出家兎腸管, 子宮及ビ蛙心ニ於テ, 骨炭ノ外, 白陶土, 滑石, 硫酸「バリウム」及ビ「アラビアゴム」ヲ吸着相トシ, 種々ノ毒物吸着作用ニ關スル生物學的研究ヲ行ヒ, 大要次ノ如キ結論ヲ得タリ. 物理學上吸着相トシテ知ラレタル骨炭, 白陶土, 滑石, 硫酸「バリウム」及ビ「アラビアゴム」ハ生物學的實驗ニ於テモ亦其吸着現象ニヨリ解毒作用ヲ呈スルヲ認メ, 且夫等吸着相ノ諸種毒物ニ對スル吸着ノ量的關係ヲ明ラカニスルコトヲ得タリ. 如上ノ諸吸着相ハ, 毒物ノ營養液中ニ溶解セルモノハ勿論, 既ニ臟器組織内ニ侵入セルモノヲモ尚良ク吸着脱取シテ其作用ヲ消失セシム. 而シテ其際吸着セラレ得ベキ毒物最大量ハ兩者ノ場合ニ於テ殆ンド差異ヲ呈セズ. 各吸着相ノ吸着能力ヲ比較スルニ, 骨炭ハ其力最モ顯著ニシテ白陶土, 滑石及ビ「アラビアゴム」ハ其力著シク劣リ, 硫酸「バリウム」ニ至リテハ其力微弱ニシテ骨炭ト比較ス可クモアラズ. 同一吸着相ニ吸着セラルル毒物ノ量ハ, 其種類ニヨリテ大差アルヲ認メタリ. 余ノ實驗成績ニ據レバ一定量ノ吸着相ニ吸着セラルル毒物量ハ, 濃度ヲ増スニ從ツテ比較的減少スルヲ見タリ. 之ハ物理學的實驗ト全ク一致スル所ナルガ, 例外トシテ「ビロカルビン」及ビ「ストロフアンチン」ハ之レニ反シテ濃度ヲ増セバ被吸着量ハ吸着相増加トノ比例以上ニ増加スルヲ認メタリ. 本實驗ニ於テ吸着作用ハ頗ル迅速ニ起ルヲ見, Freundlichノ凡テ吸着現象ハ極メテ迅速ニ現ハレ數秒ニシテ一定ノ平衡状態ニ達ス, ト云ヘル事實ニ一致スルヲ認メタリ. 即チ營養液中ニ第一次吸着相ヲ, 第二次毒物ヲ注加スルトキハ, 毒物ハ直チニ吸着セラレテ其作用ハ全ク表ハレザルカ, 或ハ現ハルルモ甚ダ微弱ニシテ直チニ正常ニ恢復スルヲ見ル. 之レニ反シ, 第一次毒物ヲ注加シ其作用ヲ臟器ニ及ボシタル後, 第二次吸着相ヲ加ヘ其毒物ヲ吸着脱取セシメテ臟器ノ官能ヲ恢復セシムルニハ, 毒物ノ種類ニヨリテ著シク時間的差異アルヲ見ル. 「ビロカルビン」「アドレナリン」及ビ「コカイン」等ニ對シテハ容易ニ其官能ヲ恢復セシメ得ルモ, 「ストロフアンチン」ノ如キ「デイギタリス」屬ノ通有性トシテ組織ト堅ク結合スル毒物ニ對シテハ, 臟器ノ官能ヲ恢復セシムルニ甚ダ長時間ヲ要スルヲ認メタリ. 實驗方法トシテ, 吸着相ノ器底ニ沈滯スルヲ防ギ可及的平等ニ營養液中ニ浮遊セシメンガ爲四本ノ通氣嘴管ト一個ノ攪拌器トヲ設ケタルガ, 甚好成績ヲ收メ得タリ. 上述各吸着相特ニ骨炭ノ如キ吸着作用顯著ナルモノハ, 解毒ヲ目的トスル治療的應用ニ向ツテ効果確實ナル可キハ勿論ナレドモ, 爾他ノ吸着相ノ如キ吸着能力比較的微弱ナルモノト雖モ, 之レヲ他ノ藥物ト併用スルニ際シテハ, 其作用ヲ減弱乃至遲延セシムル虞アルハ實地上看過ス可カラザル事實ナリト云フ可シ

Measurement of High Temperature Thermodynamic Propertiesof Several Binary Alkali Silicate Glasses

The method for continuous measurement of the high temperature heat content, developed by W.Oelsen et al. and applied to the glasses by M.Tashiro, was examined and modified in some points. Relations between the temperature and heat contents referred to the standard temperature 25℃, were determined for the some glasses of R(2)O-SiO(2) system, and the specific heats as well as the entropies were calculated. Comparing the results, some views have been obtained relating to the effect of the species and content of alkali ions on the thermodynamic quantities of such glasses

Diffusion through the Interface between Viscous Liquids in a Laminar Flow (Diffusion in a Laminar Flow)

Studies were carried out in order to know in some detail the transport phenomena through the interface in the viscous liquid moving in laminar flow. Experiments were carried out using ca. 88% glycerin solution, one added with an acid, and the other with alkali together with a small amount of phenolphthalein. Acidic glycerin solution was supplied to a long transparent cuvette of rectangular cross section through which the liquid was made to move slowly enough to establish the laminar flow, thin cords of coloured basic solution were introduced in the direction normal to the axis of flow at regular time intervals. The so obtained patterns of bending cords shortening in regular succession were photographed also at regular time intervals. The authors attribute the origin of the changing patterns of the cords to the velocity gradient existing in the acidic solution which accelerates the diffusion by increasing the concentration gradient near the cords as well as the increase of the interfacial area, and also the decrease of the thickness of the cords. Based on these idea a mathematical analysis was carried out and was obtained an equation which gives the change of the concentration distribution of two dimensional cords. Fair agreement was obtained between the results of mathematical analysis and those of experiments. Furthermore, the influence of the thickness of the cords, and that of the velocity gradient as well as of the diffusion coefficient on the concentration at the center of the cords were discussed

Apparatus for X-ray Diffraction of Liquid Metals and Several Results

A high temperature attachment for X-ray diffraction of liquid metals has been built enabling liquid metal sample to be measured at temperatures up to 1000℃ in vacuum, whilst scanning angles from 0 to 130°of 2θ. The usefulness of this apparatus was demonstrated by obtaining the structure factors of liquid Al, Pb, Sn, and Bi at several temperatures from the measured X-ray intensities and a comparison was made with those found in earlier works. Numerical values of the structure factors obtained in this work were illustrated