Biology subjects

Murase, T.

Publications and source records attributed to Murase, T..

3 recordsLinked to original sources

bioRxiv2020

Intermitochondrial signaling regulates the uniform distribution of stationary mitochondria in axons

In the central nervous system, many neurons develop axonal arbors that are crucial for information processing. Previous studies have demonstrated that premature axons contain motile and stationary mitochondria, and their balance is important for axonal arborization. However, the mechanisms by which neurons determine the positions of stationary mitochondria as well as their turnover remain to be elucidated. In this study, we investigated the regulation of spatiotemporal group dynamics of stationary mitochondria. We observed that the distribution of stationary mitochondrial spots along the unmyelinated and nonsynaptic axons is not random but rather relatively uniform both in vitro and in vivo. Intriguingly, whereas the positions of each mitochondrial spot changed over time, the overall distribution remained uniform. In addition, local inactivation of mitochondria inhibited the translocation of mitochondrial spots in adjacent axonal regions, suggesting that functional mitochondria enhance the motility of neighboring mitochondria. Furthermore, we showed that the ATP concentration was relatively high around mitochondria, and treating axons with phosphocreatine, which supplies ATP, reduced the immobile mitochondria induced by local mitochondrial inhibition. These observations indicate that intermitochondrial interactions, mediated by ATP signaling, control the uniform distribution of axonal mitochondria. The present study reveals a novel cellular system that collectively regulates stationary mitochondria in axons.

neuroscience↗

bioRxiv2020

Resting-state functional connectivity predicts recovery from visually induced motion sickness

Movies depicting certain types of motion often provoke uncomfortable symptoms similar to motion sickness, termed visually induced motion sickness (VIMS). VIMS generally evolves slowly during the viewing of a motion stimulus and, when the stimulus is removed, the recovery proceeds over time. Recent human neuroimaging studies have provided new insights into the neural bases underlying the evolution of VIMS. In contrast, no study has investigated the neural bases underlying the recovery from VIMS. Study of the recovery process is critical for the development of a way to promote recovery and could provide further clues for understanding the mechanisms of VIMS. We thus investigated brain activity during the recovery from VIMS with functional connectivity (FC) magnetic resonance imaging. We found enhanced recovery-related FC patterns involving brain areas such as the insular, cingulate, and visual cortical regions, which have been suggested to play important roles in the emergence of VIMS. These regions also constituted large interactive networks. Furthermore, the increase in FC was correlated with the subjective awareness of recovery for the following 5 pairs of brain regions: insula-superior temporal gyrus, claustrum-left and right inferior parietal lobules, claustrum-superior temporal gyrus, and superior frontal gyrus-lentiform nucleus. Considering the previous findings on the functions of these regions and the present findings, it is suggested that the increase in FC may reflect brain processes such as enhanced interoceptive awareness to ones own bodily state, a neuroplastic change in visual processing circuits, and/or the maintenance of visual spatial memory.

neuroscience↗

bioRxiv2020

Circumstances and factors of sleep-related sudden infant deaths in Japan

Background Sudden unexpected death in infancy (SUDI) comprises both natural and unnatural causes of death. However, a few epidemiological surveys have investigated SUDI in Japan.Objective This retrospective study was conducted to investigate the recent trends of circumstances and risk factors of sleep-related SUDI cases.Methods Forensic pathology sections from eight universities participated in the selection of subjects from 2013 to 2018. Data obtained from the checklist form were analyzed based on information at postmortem.Results There were 259 SUDI cases consisting of 145 male infants and 114 female infants with a mean birth weight of 2888 ± 553 and 2750 ± 370 g, respectively. Deaths most frequently occurred among infants at 1 month of age (18%). According to population-based analyses, the odds ratio (95% confidence interval) of mother’s age ≤19 years was 11.1 (6.9–17.7) compared with ages 30–39. The odds ratio for the fourth- and later born infants was 5.2 (3.4–7.9) compared with the frequency of first-born infants. The most frequent time of day for discovery was between 7 and 8 o’clock. Co-sleeping was recorded for 61%, and the prone position was found for 40% of cases at discovery. Mother’s smoking habit exhibited an adds ratio of 4.5 (2.9–5.8).Conclusion This study confirmed the trends that have been observed for sudden infant death syndrome; particularly, very high odds ratios were evident for teenage mothers and later birth order in comparison with those in other developed countries. The child of a young mother tended to die within 2 months of age. To our knowledge, this is the first report of an extensive survey of sleep-related SUDI in Japan.View Full Text

pathology↗