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Biology subjects

Kinoshita, Y.

Publications and source records attributed to Kinoshita, Y..

5 recordsLinked to original sources

A model of schema learning based on biological dimensionality reduction during sleep

Reorganizing learned knowledge into generalized representations and transferring it to future learning are essential aspects of cognition, often described as schema formation and use. However, the computational and circuit mechanisms underlying these processes remain unclear. Here, we propose a theoretical model in which schemas emerge through the formation and alignment of low-dimensional neural representations. In this model, high-dimensional input patterns are reorganized into low-dimensional manifolds through replay-driven Hebbian nonlinear dimensionality reduction. Manifold alignment simultaneously maps representations with shared task structure onto a common format, enabling downstream readout circuits to be reused across tasks. The model captures three core features of schema learning: rapid learning of similar tasks by reusing low-dimensional representations from prior experience, sleep-dependent generalization to unobserved relationships in transitive inference, and compositional recombination of schemas to solve novel tasks. Together, these results suggest a potential neural mechanism for forming, aligning, and recombining low-dimensional schemas to support future learning.

neuroscience↗

Turn-taking-like temporal coordination of ultrasonic vocalizations during close-range social interactions in Mongolian gerbils (Meriones unguiculatus)

Vocal communication depends not only on the acoustic features and rate of vocalizations, but also on their timing relative to the vocalizations of others. In this study, we examined whether ultrasonic vocalizations (USVs) produced by adult female Mongolian gerbils during freely moving social interactions are temporally related to the vocal timing of a partner. Using USVCAM, we assigned each USV to an individual caller and evaluated whether brief USVs exhibit turn-taking-like temporal organization by analyzing response latency after partner calls, call overlap rate, and circular-shift surrogate data. The offset-to-onset gaps of alternating vocalizations were concentrated within a short time range, with a median of 130 ms. In addition, the call overlap rate was significantly lower in the observed data than in the circularly shifted surrogate data, indicating that USVs occurred with short latencies after partner calls while being less likely to overlap with ongoing partner calls. Furthermore, USV counts were reduced in unoperated Ctrl animals that interacted with devocalized Mute animals. These findings suggest that gerbil USVs may be coordinated in relation to partner vocal timing and vocal input. This study provides a basis for understanding rodent USVs not merely as individual vocal outputs, but as temporally organized dyadic social signals.

animal behavior and cognition↗

Multidrug-resistant Rhodococcus equi (MDR-RE): detection in East Asia confirms global spread

Macrolide (multidrug)-resistant Rhodococcus equi (MDR-RE) emerged in the early 2000s and has since been disseminating across equine farms in the United States. In 2016, it was found in Ireland, presumably introduced through horse imports. Here, we report its identification in Japan, together with evidence of its presence in China. A recent isolate from Ireland suggests ongoing importation events. These findings highlight the continued international spread of MDR-RE and its potential to become globally established. Currently circulating among horses, MDR-RE is likely to arise in humans over time. Active surveillance is essential to monitor and control this emerging zoonotic antimicrobial resistance threat worldwide.

microbiology↗

Fetal Kidney Transplantation for In Utero Fetuses

Potter sequence, characterized by bilateral renal agenesis, oligohydramnios, and consequent pulmonary hypoplasia, presents a significant challenge in the management of affected neonates. Due to their prematurity and associated abdominal complications, these infants often fail to reach a stage where dialysis can be safely initiated and sustained, leading to an exceedingly high mortality rate. Therefore, there is hopeful anticipation that interventions serving as a bridge to achieve a state where dialysis can be safely performed will markedly improve life expectancy. We have developed a unique approach of "transplantation of fetal kidneys from a different species during the fetal period" as a bridge therapy until stable dialysis therapy can be implemented. This is a new concept of fetal therapy, targeting the fetus in utero and utilizing fetal kidneys of an appropriate size for transplantation. In this study, we first validated the approach using allogeneic transplantation. Fetal kidneys with bladders from GFP-expressing rats (gestational age 14.0-16.5 days) were transplanted subcutaneously into allogeneic rat fetuses in utero (gestational age 18.0-18.5 days) using a special needle transuterinally, and live pups were successfully obtained. The transplanted fetal kidneys with bladders were confirmed to have urine production capability. By periodic aspiration of the subcutaneous urinary cyst after birth, urine produced by the transplanted fetal kidney was successfully drained outside the body for an extended period (up to 150 days). Biochemical tests confirmed the solute removal capacity of the transplanted fetal kidney. Furthermore, despite allogeneic transplantation, long-term urine production was sustained without the use of immunosuppressants, confirming that organ transplantation into fetuses is associated with lower rejection compared to adult transplantation. Next, xenotransplantation was performed. When GFP-expressing mouse fetal kidneys (gestational age 13.0-13.5 days) were transplanted into rat fetuses in utero, maturation of renal tissue structures was confirmed even in the interspecies setting.

bioengineering↗

Histone Deacetylase 2 (HDAC2) influences maturation and mitochondrial dynamics in human induced pluripotent stem cell derived neurons.

Histone deacetylase 2 (HDAC2) is a major HDAC protein in the adult brain and has been shown to regulate many neuronal genes. Aberrant expression of HDAC2 and subsequent dysregulation of neuronal gene expression is implicated in neurodegeneration and brain aging. Human induced pluripotent stem cell-derived neurons (hiPSC-Ns) are widely used models for studying neurodegenerative disease mechanisms, but the role of HDAC2 in hiPSC-N differentiation and maturation has not been explored. In this study, we show that levels of HDAC2 progressively decrease as hiPSCs are differentiated towards neurons. This suppression of HDAC2 inversely corresponds to an increase in neuron-specific isoforms of Endophilin-B1, a multifunctional protein involved in mitochondrial dynamics. Expression of neuron-specific isoforms of Endophilin-B1 is accompanied by concomitant expression of a neuron-specific alternative splicing factor, SRRM4. Manipulation of HDAC2 and Endophilin-B1 using lentiviral approaches shows that knock-down of HDAC2 or overexpression of a neuron-specific Endophilin-B1 isoform promotes mitochondrial elongation and protects against cytotoxic stress in hiPSC-Ns, while HDAC2 knock-down specifically influences genes regulating mitochondrial dynamics and synaptogenesis. Furthermore, HDAC2 knock-down promotes enhanced mitochondrial respiration and reduces levels of neurotoxic amyloid beta peptides. Collectively, our study demonstrates a role for HDAC2 in hiPSC-neuronal differentiation, highlights neuron-specific isoforms of Endophilin-B1 as a marker of differentiating hiPSC-Ns, and demonstrates that HDAC2 regulates key neuronal and mitochondrial pathways in hiPSC-Ns.

neuroscience↗