Transfer entropy dependent on distance among agents in quantifying leader-follower relationships.

Synchronized movement of (both unicellular and multicellular) systems can be observed almost everywhere. Understanding of how organisms are regulated to synchronized behavior is one of the challenging issues in the field of collective motion. It is hypothesized that one or a few agents in a group regulate(s) the dynamics of the whole collective, known as leader(s).

A computational model of the epidermis with the deformable dermis and its application to skin diseases.

The skin barrier is provided by the organized multi-layer structure of epidermal cells, which is dynamically maintained by a continuous supply of cells from the basal layer. The epidermal homeostasis can be disrupted by various skin diseases, which often cause morphological changes not only in the epidermis but in the dermis. We present a three-dimensional agent-based computational model of the epidermis that takes into account the deformability of the dermis.

Intracellular trafficking of Notch orchestrates temporal dynamics of Notch activity in the fly brain.

While Delta non-autonomously activates Notch in neighboring cells, it autonomously inactivates Notch through cis-inhibition, the molecular mechanism and biological roles of which remain elusive. The wave of differentiation in the Drosophila brain, the 'proneural wave', is an excellent model for studying Notch signaling in vivo. Here, we show that strong nonlinearity in cis-inhibition reproduces the second peak of Notch activity behind the proneural wave in silico.

Substrate membrane bearing close-packed array of micron-level pillars incrassates air-exposed three-dimensional epidermal equivalent model.

Background: We showed previously that a thick three-dimensional epidermal equivalent can be constructed with passaged keratinocytes on a patterned surface.

Material And Methods: We first carried out computer simulations of a three-dimensional epidermal equivalent model built on close-packed arrays of 10 µm, 15 µm, 20 µm, 30 µm, and 60 µm diameter pillars. Based on these predictions, we evaluated epidermal equivalents built on a series of porous plastic membranes bearing arrays of pillars 15 µm, 20 µm, 25 µm, 30 µm, and 50 µm in diameter.

An information-theoretic approach to infer the underlying interaction domain among elements from finite length trajectories in a noisy environment.

Transfer entropy in information theory was recently demonstrated [Basak et al., Phys. Rev.

A surfactant reaction model for the reciprocating motion of a self-propelled droplet.

We report herein experimental observations of the reciprocating motion of a self-propelled droplet floating on the surface of an aqueous surfactant solution and a simple reaction model capable of reproducing the observed behavior of the droplet. The reciprocating motion was observed in a quasi-one-dimensional annular channel, so the reciprocation was not caused by reflections at boundaries. To understand the reciprocation, our model assumes a reaction between the surface active substance emitted from the droplet and surfactants dissolved in the aqueous solution.

Inferring domain of interactions among particles from ensemble of trajectories.

An information-theoretic scheme is proposed to estimate the underlying domain of interactions and the timescale of the interactions for many-particle systems. The crux is the application of transfer entropy which measures the amount of information transferred from one variable to another, and the introduction of a "cutoff distance variable" which specifies the distance within which pairs of particles are taken into account in the estimation of transfer entropy. The Vicsek model often studied as a metaphor of collectively moving animals is employed with introducing asymmetric interactions and an interaction timescale.

Mathematical models and deep learning for predicting the number of individuals reported to be infected with SARS-CoV-2.

We introduce a novel methodology for predicting the time evolution of the number of individuals in a given country reported to be infected with SARS-CoV-2. This methodology, which is based on the synergy of explicit mathematical formulae and deep learning networks, yields algorithms whose input is only the existing data in the given country of the accumulative number of individuals who are reported to be infected. The analytical formulae involve several constant parameters that were determined from the available data using an error-minimizing algorithm.

The Role of Serotonin in the Influence of Intense Locomotion on the Behavior Under Uncertainty in the Mollusk .

The role of serotonin in the immediate and delayed influence of physical exercise on brain functions has been intensively studied in mammals. Recently, immediate effects of intense locomotion on the decision-making under uncertainty were reported in the Great Pond snail, (Korshunova et al., 2016).

Live imaging of alterations in cellular morphology and organelles during cornification using an epidermal equivalent model.

The stratum corneum plays a crucial role in epidermal barrier function. Various changes occur in granular cells at the uppermost stratum granulosum during cornification. To understand the temporal details of this process, we visualized the cell shape and organelles of cornifying keratinocytes in a living human epidermal equivalent model.

Microinjection support system for small biological subjects.

In biological research, various experiments such as behavioral experiments and physiological ones are often conducted with pharmacologically treated animals. In such experiments, it is necessary to inject the same volume of solution into numerous small animals, such as insects to prepare several experimental subjects. However, repeating manual injections is burdensome, and it is also difficult to maintain injection quality and consistency.

Flexible Coordination of Flexible Limbs: Decentralized Control Scheme for Inter- and Intra-Limb Coordination in Brittle Stars' Locomotion.

Conventional mobile robots have difficulties adapting to unpredictable environments or performing adequately after undergoing physical damages in realtime operation, unlike animals. We address this issue by focusing on brittle stars, an echinoderm related to starfish. Most brittle stars have five flexible arms, and they can coordinate among the arms (i.

A general model of locomotion of brittle stars with a variable number of arms.

Typical brittle stars have five radially symmetrical arms that coordinate to move the body in a certain direction. However, some species have a variable number of arms, which is a unique trait since intact animals normally have a fixed number of limbs. How does a single species manage different numbers of appendages for adaptive locomotion? We herein describe locomotion in with four, five, six and seven arms to propose a common rule for the movement of brittle stars with different numbers of arms.

Decentralized Control Mechanism for Determination of Moving Direction in Brittle Stars With Penta-Radially Symmetric Body.

A brittle star, an echinoderm with penta-radially symmetric body, can make decisions about its moving direction and move adapting to various circumstances despite lacking a central nervous system and instead possessing a rather simple distributed nervous system. In this study, we aimed to elucidate the essential control mechanism underlying the determination of moving direction in brittle stars. Based on behavioral findings on brittle stars whose nervous systems were lesioned in various ways, we propose a phenomenological mathematical model.

Uni-cellular integration of complex spatial information in slime moulds and ciliates.

Single-celled organisms show a fascinating faculty for integrating spatial information and adapting their behaviour accordingly. As such they are of potential interest for elucidating fundamental mechanisms of developmental biology. In this mini-review we highlight current research on two organisms, the true slime mould Physarum polycephalum and the ciliates Paramecium and Tetrahymena.

Raman spectroscopic histology using machine learning for nonalcoholic fatty liver disease.

Histopathology requires the expertise of specialists to diagnose morphological features of cells and tissues. Raman imaging can provide additional biochemical information to benefit histological disease diagnosis. Using a dietary model of nonalcoholic fatty liver disease in rats, we combine Raman imaging with machine learning and information theory to evaluate cellular-level information in liver tissue samples.

Defecation initiates walking in the cricket Gryllus bimaculatus.

Feces provides information about the donor and potentially attracts both conspecifics and predators and also parasites. The excretory system must be coordinated with other behaviors in insects. We found that crickets started walking forward following defecation.

The function of the ophiuroid nerve ring: how a decentralized nervous system controls coordinated locomotion.

Echinoderms lack a centralized nervous control system, yet each extant echinoderm class has evolved unique and effective strategies for locomotion. Brittle stars (Ophiuroidea) stride swiftly over the seafloor by coordinating motions of their five muscular arms. Their arms consist of many repeating segments, requiring them to use a complex control system to coordinate motions among segments and between arms.

Immediate-Early Promoter-Driven Transgenic Reporter System for Neuroethological Research in a Hemimetabolous Insect.

Genes expressed in response to increased neuronal activity are widely used as activity markers in recent behavioral neuroscience. In the present study, we established transgenic reporter system for whole-brain activity mapping in the two-spotted cricket , a hemimetabolous insect used in neuroethology and behavioral ecology. In the cricket brain, a homolog of () was rapidly induced as an immediate-early gene (IEG) in response to neuronal hyperexcitability.

A Novel Metal-Based Imaging Probe for Targeted Dual-Modality SPECT/MR Imaging of Angiogenesis.

Superparamagnetic iron oxide nanoparticles with well-integrated multimodality imaging properties have generated increasing research interest in the past decade, especially when it comes to the targeted imaging of tumors. Bevacizumab (BCZM) on the other hand is a well-known and widely applied monoclonal antibody recognizing VEGF-A, which is overexpressed in angiogenesis. The aim of this proof-of-concept study was to develop a dual-modality nanoplatform for targeted single photon computed emission tomography (SPECT) and magnetic resonance imaging (MRI) of tumor vascularization.

Comparison of brain monoamine content in three populations of that correlates with taste-aversive learning ability.

To find a causal mechanism of learning and memory is a heuristically important topic in neuroscience. In the pond snail , the following experimental facts have accrued regarding a classical conditioning procedure known as conditioned taste aversion (CTA): (1) one-day food-deprived Dutch snails have superior CTA memory formation; (2) the one-day food-deprived snails have a low monoamine content (e.g.

Tyraminergic modulation of agonistic outcomes in crayfish.

Octopamine, a biogenic amine, modulates various behaviors, ranging from locomotion and aggression to learning and memory in invertebrates. Several studies recently demonstrated that tyramine, the biological precursor of octopamine, also affects behaviors independent of octopamine. Here we investigated the involvement of tyramine in agonistic interaction of the male crayfish Procambarus clarkii.

A brittle star-like robot capable of immediately adapting to unexpected physical damage.

A major challenge in robotic design is enabling robots to immediately adapt to unexpected physical damage. However, conventional robots require considerable time (more than several tens of seconds) for adaptation because the process entails high computational costs. To overcome this problem, we focus on a brittle star-a primitive creature with expendable body parts.