The Neurophysiological Implications of an Atypical Slow Negative Potential in Short Interval CNV Paradigm

We recorded a slow negative potential from Cz (10/20 method) in 49 healthy students (12 male, 37 female, mean age 19.1) by a short interstumulus interval CNV paradigm. The interstimulus interval was 2 or 3 seconds, the warning stimulus presented at random or regular interval at 0.2 Hz. An atypical negative variation with two separated negative peaks was recorded in 26.0-30.6% trials regardless of interstimulus interval or modality of warning stimulus presentation, while a typical CNV was recorded in 32.0-59.2% of trials. No apparent negative variation was recorded in 14.3-18.4% in 2 seconds interstimulus interval, and 28-38% in 3 seconds interstimulus interval, showing that 2 seconds interval is better to get stable CNV recording than 3 seconds interval. The first negative wave of the atypical negative variation was 692-799msec in duration, but frequently prolonged to 1000msec or more in 3 seconds interval. It usually had negative peak around 900-1100msec, but sometimes around 1500msec. This features are different from any reported negative components of CNV. The second negative wave began 800-1200msec before second stimulus, and had its peak just before second stimulus, showing common features with readiness potential. The appearance of CNV was unsatble in the students in which the atypical negative variation was recorded in regular, 2 seconds intersitimulus interval, and the amplitude of slow vertex response and pattern reversal visual evoked potential was lower in thses students than in the students in which a typical CNV was recorded more than 3 times in total 4 times of trials. These findings indicate that the atypical variation observed in this study is due to a lowered arousal level or cortical neuronal activity, rather than a separated appearance of different components of CNV.CNVの記録条件を検討する目的で、健康若年成人49名（男12、女37）を対象にS(1)-S(2)+Rパラダイムを用いてCNVを記録した。S(1)-S(2)間隔2秒のほうが3秒よりも安定してCNVが記録されたが、刺激間隔とは無関係に26～30％の試行で二峰性の陰性変動をもつ非定型な緩電位が記録された。この緩電位は同一被検者でも出現性が一貫せず、個体差よりも被検者の状態に依存していた。二峰性陰性波のうち、後期成分は準備電位に対応するものと思われたが、前期成分はS(1)後900～1100msecにピークをもつ陰性波で、これまで報告されたCNVの要素波とは対応しなかった。また、この非定型CNVを示す被検者ではCNV出現が不安定で、SVRおよびパターンVEPの振幅が低い傾向があり、試行時の被検者の覚醒水準低下よるものではないかと考えられた

Role of multiple subband renormalization in the electronic transport of correlated oxide superlattices

Metallic behavior of band-insulator/ Mott-insulator interfaces was observed in artificial perovskite superlattices such as in nanoscale SrTiO3/LaTiO3 multilayers. Applying a semiclassical perspective to the parallel electronic transport we identify two major ingredients relevant for such systems: i) the quantum confinement of the conduction electrons (superlattice modulation) leads to a complex, quasi-two dimensional subband structure with both hole- and electron-like Fermi surfaces. ii) strong electron-electron interaction requires a substantial renormalization of the quasi-particle dispersion. We characterize this renormalization by two sets of parameters, namely, the quasi-particle weight and the induced particle-hole asymmetry of each partially filled subband. In our study, the quasi-particle dispersion is calculated self-consistently as function of microscopic parameters using the slave-boson mean-field approximation introduced by Kotliar and Ruckenstein. We discuss the consequences of strong local correlations on the normal-state free-carrier response in the optical conductivity and on the thermoelectric effects.Comment: 11 pages, 4 figure

頸椎症性脊髄症における椎間関節変性の有病率と臨床的影響：CT新分類での検討

Objective: To evaluate cervical facet joint degeneration using a newly developed classification, investigate its prevalence and relationship with cervical degenerative spondylolisthesis, and clarify its clinical significance in patients with degenerative cervical myelopathy (DCM). Methods: This study included 145 consecutive patients with DCM who underwent surgical treatment. Clinical variables and radiological findings were analyzed. A new 6-grade computed tomography (CT) classification for cervical facet joint degeneration was adapted, and its prevalence was evaluated by categorizing the joints into those at responsible and those at nonresponsible spinal segmental levels. We evaluated the association between rapidly progressive myelopathy and the presence of significant facet joint degeneration or spondylolisthesis at the responsible segmental level. Results: Finally, 140 patients with a mean age of 64.1±12.8 years were analyzed. The prevalence of grade 1, 2, 3, 4, 5A, and 5B classification in all facet joints was 72.0%, 9.5%, 10.9%, 4.3%, 2.9%, and 0.4%, respectively. There was a statistically significant difference in the distribution of CT grades between the joints at the responsible and nonresponsible segmental levels (p<0.001), with a high prevalence of grade 4 or 5B degeneration at the responsible segmental level, reflecting articular irregularity. There was also a statistically significant relationship between rapidly progressive myelopathy and grade 4 or 5B degeneration at the responsible segmental level (p<0.001), but not between rapidly progressive myelopathy and spondylolisthesis (p=0.255). Conclusion: This novel CT classification for facet joints deserves additional evaluation in patients with DCM. Abnormal findings on the articular surfaces might be related to the progression of myelopathy.博士（医学）・甲第870号・令和5年3月15

Magnetic effects at the interface between nonmagnetic oxides

The electronic reconstruction at the interface between two insulating oxides can give rise to a highly-conductive interface. In analogy to this remarkable interface-induced conductivity we show how, additionally, magnetism can be induced at the interface between the otherwise nonmagnetic insulating perovskites SrTiO3 and LaAlO3. A large negative magnetoresistance of the interface is found, together with a logarithmic temperature dependence of the sheet resistance. At low temperatures, the sheet resistance reveals magnetic hysteresis. Magnetic ordering is a key issue in solid-state science and its underlying mechanisms are still the subject of intense research. In particular, the interplay between localized magnetic moments and the spin of itinerant conduction electrons in a solid gives rise to intriguing many-body effects such as Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions, the Kondo effect, and carrier-induced ferromagnetism in diluted magnetic semiconductors. The conducting oxide interface now provides a versatile system to induce and manipulate magnetic moments in otherwise nonmagnetic materials.Comment: Nature Materials, July issu

Electronic and Magnetic Structures of Sr2FeMoO6

We have investigated the electronic and magnetic structures of Sr2FeMoO6 employing site-specific direct probes, namely x-ray absorption spectroscopy with linearly and circularly polarized photons. In contrast to some previous suggestions, the results clearly establish that Fe is in the formal trivalent state in this compound. With the help of circularly polarized light, it is unambiguously shown that the moment at the Mo sites is below the limit of detection (< 0.25mu_B), resolving a previous controversy. We also show that the decrease of the observed moment in magnetization measurements from the theoretically expected value is driven by the presence of mis-site disorder between Fe and Mo sites.Comment: To appear in Physical Review Letter