Spontaneous and stimulus-induced coherent states of critically balanced neuronal networks

How the information microscopically processed by individual neurons is integrated and used in organizing the behavior of an animal is a central question in neuroscience. The coherence of neuronal dynamics over different scales has been suggested as a clue to the mechanisms underlying this integration. Balanced excitation and inhibition may amplify microscopic fluctuations to a macroscopic level, thus providing a mechanism for generating coherent multiscale dynamics. Previous theories of brain dynamics, however, were restricted to cases in which inhibition dominated excitation and suppressed fluctuations in the macroscopic population activity. In the present study, we investigate the dynamics of neuronal networks at a critical point between excitation-dominant and inhibition-dominant states. In these networks, the microscopic fluctuations are amplified by the strong excitation and inhibition to drive the macroscopic dynamics, while the macroscopic dynamics determine the statistics of the microscopic fluctuations. Developing a novel type of mean-field theory applicable to this class of interscale interactions, we show that the amplification mechanism generates spontaneous, irregular macroscopic rhythms similar to those observed in the brain. Through the same mechanism, microscopic inputs to a small number of neurons effectively entrain the dynamics of the whole network. These network dynamics undergo a probabilistic transition to a coherent state, as the magnitude of either the balanced excitation and inhibition or the external inputs is increased. Our mean-field theory successfully predicts the behavior of this model. Furthermore, we numerically demonstrate that the coherent dynamics can be used for state-dependent read-out of information from the network. These results show a novel form of neuronal information processing that connects neuronal dynamics on different scales.Comment: 20 pages 12 figures (main text) + 23 pages 6 figures (Appendix); Some of the results have been removed in the revision in order to reduce the volume. See the previous version for more result

Long-range correlation in sheared granular fluids

The spatial correlation function of the momentum density in the three-dimensional dilute sheared granular fluids is theoretically investigated. The existence of the long-range correlation is verified through both the analytic calculation and the numerical simulation.Comment: 6 pages, 1 figure

Effects of clearcutting and girdling on soil respiration and fluxes of dissolved organic carbon and nitrogen in a Japanese cedar plantation

Impacts of forest management practices on soil carbon (C) and nitrogen (N) dynamics remain under debate due to complex interactions between belowground biogeochemical processes. To optimize practices that minimize soil C and N losses, we investigated the effects of management practices on soil C and N fluxes, including the leaching of dissolved organic C (DOC) and N, by comparing clearcutting, stem girdling (removal of the bark and phloem tissue), and control treatments in a Japanese cedar plantation. Canopy opening by clearcutting is hypothesized to have a greater effect on soil C loss and the leaching of nitrate-N relative to girdling. Results showed that clearcutting increased soil heterotrophic respiration (organic matter decomposition) and lead to a loss of soil organic C (2.9–3.7 Mg C ha⁻¹ yr⁻¹). Higher litter inputs from girdled tree dieback caused an increase in DOC fluxes from the organic horizon, whereas the loss of fresh litter inputs decreased DOC fluxes from the organic horizon following clearcutting. Clearcutting increased nitrate-N leaching by 3.3–4.8 kg N ha⁻¹ yr⁻¹ due to the loss of plant N uptake and the increased mineralization of soil organic matter, but high C/N ratios in dissolved organic matter limited nitrate leaching in the girdled treatment. Effects of forest management practices on soil C loss and nitrate leaching loss could be variable, but the slash application in clearcutting and the slow dieback in stem girdling could mitigate soil C loss and nitrate leaching loss

Female chimpanzees giving first birth in their natal group in Mahale: attention to incest between brothers and sisters

出自集団で出産するメスは「例外」ではないことを解明 --チンパンジー父系社会でメスが出自集団に居残る要因の検討--. 京都大学プレスリリース. 2021-01-15.Chimpanzee societies generally show male philopatry and female dispersal. However, demographic data on wild chimpanzee societies from long-term study sites have revealed that some females give birth in their natal group (i.e., “remaining females”). Here, we report two remaining females in the M group in Mahale, Tanzania, and compare their cases with previous reports to explore the social and ecological factors that lead to females remaining in their natal group. The results revealed that neither the social traits of the remaining females nor the ecological factors they experienced showed a coherent trend. However, we found multiple, non-mutually exclusive potential factors that may influence the decision by females to remain in their natal group: a decrease in indirect feeding competition, support from mothers or allomothers in the care of offspring and in aggressive interactions with other individuals, close relationships with the other remaining females, and a short adolescent infertility period. Additionally, we observed a natal female copulating with her older brother, which was the first observation of brother–sister incest in Mahale. Although DNA analysis revealed that her infant was not a product of inbreeding, the pair copulated frequently in the latter half of her estrus period, suggesting that they did not avoid incest behaviorally to avoid inbreeding. Furthermore, there was no hard evidence that the remaining female avoided mating with her maternal brother, suggesting that incest avoidance may not be a proximate factor responsible for female dispersal

Reconnaissance on Liquefaction-induced Flow Failure Caused by the 2018 Mw 7.5 Sulawesi Earthquake, Palu, Indonesia

The Mw 7.5 Sulawesi Earthquake 2018 was a catastrophic disaster that resulted in large numbers of casualties. This study aimed to investigate the damages of liquefaction-induced-flow failure in three areas in Palu city, i.e. Petobo, Balaroa, and Jono Oge. It was found that this flow failure occurred on a large scale at a very gentle ground inclination, ranging from 1 to 3%. In order to gain an understanding of the soil conditions in these specific locations, Portable Dynamic Cone Penetration Tests were conducted in Petobo. The results showed that the soil layers in the affected area were in a loose state compared to the non-affected areas. Furthermore, some spots of freshwater inundation were recognized in Petobo and Balaroa, even two weeks after the disaster. Based on this evidence, a mechanism of liquefaction-induced-flow failure caused by a confined aquifer is proposed

Association of initial lactate levels and red blood cell transfusion strategy with outcomes after severe trauma: a post hoc analysis of the RESTRIC trial

Background The appropriateness of a restrictive transfusion strategy for those with active bleeding after traumatic injury remains uncertain. Given the association between tissue hypoxia and lactate levels, we hypothesized that the optimal transfusion strategy may differ based on lactate levels. This post hoc analysis of the RESTRIC trial sought to investigate the association between transfusion strategies and patient outcomes based on initial lactate levels. Methods We performed a post hoc analysis of the RESTRIC trial, a cluster-randomized, crossover, non-inferiority multicenter trials, comparing a restrictive and liberal red blood cell transfusion strategy for adult trauma patients at risk of major bleeding. This was conducted during the initial phase of trauma resuscitation; from emergency department arrival up to 7 days after hospital admission or intensive care unit (ICU) discharge. Patients were grouped by lactate levels at emergency department arrival: low ( Results Of the 422 RESTRIC trial participants, 396 were analyzed, with low (n = 131), middle (n = 113), and high (n = 152) lactate. Across all lactate groups, 28 days mortality was similar between strategies. However, in the low lactate group, the restrictive approach correlated with more ICU-free (β coefficient 3.16; 95% CI 0.45 to 5.86) and ventilator-free days (β coefficient 2.72; 95% CI 0.18 to 5.26) compared to the liberal strategy. These findings persisted even after excluding patients with severe traumatic brain injury. Conclusions Our results suggest that restrictive transfusion strategy might not have a significant impact on 28-day survival rates, regardless of lactate levels. However, the liberal transfusion strategy may lead to shorter ICU- and ventilator-free days for patients with low initial blood lactate levels