English Abstract

English Abstract

Novel coronavirus 2019 (COVID-19) caused a global pandemic since the end of 2019. In Japan, this became a first instance in which mathematical models were widely used for policymaking process. In my talk, I will review how such countermeasures were designed using mathematical models, and how the interventions were evaluated. In particular, following subjects are covered:

1. Cluster interventions and asymptomatic transmission

2. Invasion probability and travel restrictions

3. Effective reproduction number and state of emergency

4. Countermeasures that shape the state of emergency

5. Problems surrounding statistical estimation of the reproduction number

Development of fluorescence imaging technology using fluorescent proteins has made it possible to visualize physiological functions in live sample. Nanoscopic technologies such as super-resolution imaging have also significantly progressed in recent years. However, since the irradiation of excitation light is inevitable in the fluorescence observation, problems such as phototoxicity and autofluorescence are unavoidable. On the other hand, bioluminescence imaging using luciferase is attracting attention. Bioluminescence, unlike fluorescence, does not require external light illumination, so auto-fluorescence and phototoxicity cannot cause. This advantage of bioluminescence over fluorescence has been recognized for some time, but because the emission signal is weak, it requires long exposure times of tens of minutes and has not been used for live imaging. Recently, however, bright bioluminescent proteins such as NanoLuc, Nano-lantern, and Akaluc have been developed, and live imaging by the bioluminescence has begun to be realized. In addition, some bioluminescent systems have been able to biosynthesize luminescent substrates, producing fully spontaneous animals and plants. In this lecture, I will introduce recent progress on technology development related to fluorescence and bioluminescence imaging and discuss future prospects.

English Abstract

N/A

Severe natural disasters such as great earthquakes and heavy rain may ruin hospitals in the near future. Damage of the hospital building and infrastructures may harm hospital function. We should learn from lessons from the past incidents to prepare for the future. Structural damage of hospital buildings due to violent quake had occurred in the Hanshin-Awaji Great Earthquake and the 2016 Kumamoto Earthquake. Several hospitals flooded in the 2015 Jouso flood and in the 2018 West Japan heavy rainfall requiring hospital evacuation. A wide area blackout occurred in the 2011 East Japan Great Earthquake and in the 2018 Hokkaido Iburi Tobu Earthquake. Water-supply was frequently damaged in the past disasters causing discontinuation of hemodialysis and damage of the operative theater function. Shortage of fuel may disrupt hospital function in the future Nankai Trough Earthquake. Hospital Business Continuity Planning is important to maintain hospital function under severe disaster.

Many hospitals lost a power supply by Typhoon No.21 and Hokkaido Eastern Iburi Earthquake in 2018. When a hospital loses a power supply, the hospital function decreases remarkably. In this study, it was analyzed what happened at the time of these two disasters at the hospitals. As a result, a blackout caused a stop of EV and the water supply in the hospital, and greatly gave damage for the treatment of the patient. In addition, it was shown that a local blackout has given further load in a hospital. Generally, it is imaged that the power outage measures of the hospital are expensive. However, the function maintenance of the hospital is accomplished by the combination of cheap and reliable measures, for example, the purchase of the mobile battery. In particular, the medical equipment has to secure a power supply to use it at the time of a disaster continuously.

For ensuring the stable continuation of medical services during a disaster, critical hospitals that serve as a regional disaster base have prepared Business Continuity Plans (BCPs). However, the BCPs do not consider sufficiently the damage to the facilities and equipment. This study examines the extent of damage to hospital facilities in this future earthquake disaster through shaking table tests that reproduce earthquake motion and seismic response simulation of hospital building models. The threshold acceleration and velocity of floors that cause rocking and tumbling of medical equipment were identified. The strength increase factor used for the design of critical hospitals does not necessarily decrease the damage to the non-structural component and critical equipment. Assuming that hardware measures such as seismic retrofitting of buildings would be difficult, improvements to the current BCP, such as listing potentially fragile equipment, would be a realistic option in increasing hospitals' disaster resiliency.

On September 6th 2018 at 3:07 am, Hokkaido Eastern Iburi Earthquake occurred, followed by the power outage which covered whole Hokkaido. Although the hospital building had constructed 37 years ago, the building itself was not damaged. However, the outage lasted for 41 hours and had major impacts on dialysis treatments, managements of ventilators, and general medical care systems. It was also difficult to obtain the fuel required for the emergency power supply system. Thanks to the registration with EMIS (Emergency Medical Information System), we were able to promptly transfer patients to other medical institutions for continuous treatments of dialysis/ventilator. As the lessons leant from this experience, it is necessary to prepare an action card which makes each staff move without hesitations in the event of a disaster, including staffs comprehending the scale of lifelines like electricity and water supply of the facility, and preparing communication system and equipment in advance.

Dementia progresses to healthy people, PCSD, MCI and Dementia. The initial research was the development of curative for Dementia. Various imaging techniques and neuropsychological tests for diagnosis, non-drug therapy, care technologies such as robots, etc. were the research subjects. Recently, when research on curative have been stalled, the entire research has been paradigm-shifted toward pre-Dementia stage. Therefore, the research subject of BME on Dementia should be also moving toward the prevention of dementia, because I believe that synergistic effects with other technical fields are important in pursuing results. Finally, as an example, I would like to introduce the Neuropsychological Test named CWPT, which enables classification of minor brain functions before Dementia. This test has already gained evidences and has been put to practical use as a screening for local residents in Japan. We have created English version of the test. If you are interested, please contact me.

Dementia is associated with several social issues, and its prevention warrants urgent attention. Preventive interventions are effective when implemented in the pre-clinical stage of dementia (PCSD); therefore, early detection of PCSD is essential. We developed the color Kanji Pick-out Test (CKPT), a neuropsychological test to diagnose PCSD. However, there are several issues associated with the questionnaire version of the CKPT, which precludes widespread use. In an attempt to overcome these difficulties, we designed the CKPT application that can easily be administered by any individual using a common tablet device, which displays the results immediately. We are engaged in improving this application further to ensure that the orientation of the test, control of the measurement time, scoring, and feedback of the results can be performed automatically. We present an overview of the CKPT application that is currently being developed, together with its prospective uses.

At nursing care sites, life programs are implemented for improving the QOL of facility users. It is important to carefully examine the QOL items for each user, create and implement the effective life program based on this. However, facilities are busy on a daily basis, and it is not possible to devote sufficient time to developing a life program that considers the role of user. Therefore, in this study, we first selected the QOL items from the areas of "activity" and "participation" of ICF and scrutinizing based on a questionnaire survey of 355 facilities. Then, we developed a computer system that automatically generates a life program using determined QOL and creates a database of the results. This system can be used from the browser that is usually used to improve the convenience at each facility. In this paper, we discuss the details of the developed system and its use.

It has been reported that one in seven people aged 65 and over has dementia. In this study, the number of steps and activities of subjects were measured across six years using a pedometer with ICT to measure their amount of activity. Their average step count and activities, such as shopping, were observed, and their daily functioning was assessed.Many elderly people, including those with dementia, began to experience issues with their feet and toenails, such as deformities, which prevented them from leaving the house. In this study, we provided footcare to subjects with dementia (including MCI). The subjects significant improvements in their lower limb muscular strength and the mobility of their toes.Therefore, it is implied that an ICT system that assists them in visualizing walking every day, and motivates them to walk regularly is effective for people with dementia and those at high risk.

We have reviewed recent evidences of music-based therapeutic intervention for prevention of dementia and mild cognitive impairment which were reported in journals. We will present the results focusing on effects of active music therapy and playing musical instruments. We have been developing a novel accessible electronic musical instrument Cymis. We will outline our pilot study of applying Cymis with touch panel or switch to moderate-sever dementia patients in a nursing home as well as healthy seniors.

English Abstract

Recently, home artificial-organ (AO) therapies for serious organ failure, such as ventricular assist device (VAD) and home hemodialysis (HHD), have been remarkably progressing. This is because that the functions and downsizing of each artificial organs improved. Home AO therapies influence the raising of patients quality of life (QOL) and activities of daily living (ADL). Although solo therapy without a caregiver is conducting in other developed countries, the therapy has not permitted in our country yet. This is actually an inhibitory factor to proceed the home AO therapies. In the background, there is a society of seeking for zero-risk in Japan. It is important that novel technologies, such as remote medical systems and monitoring, are introduced to home AO therapies. It is expected that aggressive medical-engineering collaboration among Japanese Society for Medical and Bioengineering, Japanese Society for Artificial Organs and related-medical Societies will be a game changer to resolve the deadlock.

Treatment with an implantable ventricular assist device(iVAD) has become widespread. In the future, it is expected that home treatment under circulatory assistance using an iVAD as well as the recovery to society will be further expanded. It is indispensable to solve various problems in aiming at patient safety and security as well as medical development. It is necessary to develop home monitoring systems and simultaneous arrangements of remote or home medical care systems such as virtual medical care, home nursing, emergency medical care system, and home rehabilitation that make home monitoring systems to be effective in their utilization. How to improve safety and security in environments other than homes, such as work and school, and how to remove barriers to the social life of patients with iVADs are important issues. It is important to summarize these issues and promote their developmental solutions in collaboration with medical and engineering.

Implantable VAD treatment has already been provided to more than 1,500 patients, and the results are extremely good. However, the frequency of cases with a period of less than one year until the first readmission is as high as 60% or more. Even though, their complications can be fatal, it is believed that early response is the reason why the survival rate is better than the incidence. To overcome this, several biomedical engineering approaches are being reported. One of them is "transcutaneous energy transfer" that eliminates the skin penetration of the drive cable, which is the gateway to infection and has already started clinical use overseas. The other is "remote monitoring" which aims to quickly detect and respond to abnormalities in pumps and patients by the new communication environment, AI, etc. It is expected that medical engineering will continue to play a major role in home VAD treatment.

Home hemodialysis (HHD) is an ideal dialysis modality, by which the patient can make its dialysis program according to its own life style with a sufficient dialysis dose. HHD is rather safer than in in-center HD because the ultrafiltration volume per unit time in HHD are lower than those of in-center HD. In spite of these benefits, only 0.2% of all dialysis patients in Japan are treated by HHD. The major reasons for that are the anxiety for probable treatment-related troubles in home and the lack of an accompany person. If artificial intelligence could evaluate the severity of the trouble based on the bio-medical information, it could make a warning to the patient and the medical staffs in the hospital, or in a case to the security service. If we could complement the safeness of HHD with bio-medical engineering technologies, we could expand its benefits to more dialysis patients.

Vital signs such as core temperature and blood pressure are monitored at home for home medical care using thermometers and sphygmomanometers. These data are used to manage health and hormonal balance. However, without strong motives such as COVID-19 infection prevention, it is not easy to continue measuring vital signs at home every day. In this presentation, I will report that the toilet excretion and the TV usage as vital signs measured without the active cooperation of patients.This study was supported in part by JSPS KAKENHI Grant Number JP19K09667.

April 2018, Japanese Government listed several telemedicine service into the list of medical fee points of Japanese Health Insurance system. At that moment, the Ministry of Health, Labour and Welfare categorized telemedicine in to three sub-categories, (1) Tele-radiology or Tele-pathology, (2) Virtual doctor visit over the Internet, and (3) Remote Monitoring. While (1) and (2) are conventional telemedicine based-on multimedia communication, (3) is new telemedicine derived by the home care medical devices with network connectivity. Under current trend of clinical medicine which is changing from cure at hospital to care at home, the remote monitoring and the supporting technologies become important. In this lecture, I will introduce the guideline of information system to support remote respiratory management and discuss the plausible approaches of research and development for care with artificial organ at home.

The scales falling down from the eye" means to pierce the essence and solve problems with unique ideas. I want you to imagine the idea of going beyond Ikkyu's Tonchi. Most of research themes and solutions are by no means young. There are not many research results that can be said to be scales from the eyes because of the fashion. It is said that any field will lose its novelty after 20 years, but if a unique solution can be produced in that swamp, it will not only stand out, but will also be highly evaluated. Although the number of researchers in medical robotics has increased, there are not many outstanding ideas. Tips are new materials, new mechanisms and new standards. It is to attack from "Shin Mechatronics".

My research presents an advanced locomotion method that produces non-slipping motion in digestive organs and the abdominal cavity. New movement principle of the robot, which has a soft and deformable body that can move through a confined space is proposed. The mechanism of a toy water snake is applied to this principle. Magnetic particles inside the water balloon are affected by the external magnetic field and push the inner side of a balloon to the direction of a magnetic field. We construct an experimental model to verify the proposed principle, the sliding movement is measured using the model. Confirmatory experiments of movement are conducted in the two sheets that imitated internal organs.

The number of children born through in vitro fertilization (IVF) has been increasing every year, and is currently about one in sixteen. IVF is a treatment in which a sperm and an oocyte are taken out of the body, fertilized, and returned to the uterus to become pregnant. Repeated treatment is physically and emotionally taxing, especially for women, and the high cost of treatment is a financial burden that forces many couples to give up treatment. One of the causes that may reduce the success rate of pregnancy and increase the risk of ectopic pregnancy is that the embryo implanted in the uterus floats and does not stay in a suitable site for implantation. In this talk, I will introduce the forefront of research on "embryo transfer microrobots" that protect the embryo and transport it to the optimal position for implantation in order to solve this problem.

3D printers were rapidly becoming popular. The applications of the 3D printer was expanding not only to research application and design mockups, but also to final products. Compared to 3D printers such as Fused Deposition Modeling and Powder Sintering type, which are sold in the low price range, the micro-stereolithography method using chemical reaction had better processing accuracy. In the micro-stereolithography, liquid resin was cured by photopolymerization reaction by irradiating the liquid resin with an ultraviolet laser. High temperature heat treatment was effective for detoxifying this cytotoxic photocurable resin. Conventionally, in the micro stereolithography, heat treatment had been performed to stabilize the mechanical properties of the cured resin, but in order to detoxify the cytotoxic substance inside the photocurable resin, the treatment at higher temperature than conventional treatment was required.

In silico research, which reproduces living organisms with a numerical model, is not limited to conventional research that focuses on the elucidation of biological functions, but is currently expanding dramatically and expanding its field of activity. FDA has formulated the guidance on the use of in silico for medical device development, and the environment for medical device development and evaluation using in silico is rapidly being established. In Japan as well, its importance is increasing, as the next-generation medical device guidelines include a description of medical device evaluation using in silico. We will introduce the latest trends in in silico and medical device development / evaluation, which are leading overseas, with specific examples of devices that actually utilize in silico.

Tachyarrhythmias, such as ventricular fibrillation and atrial fibrillation, are caused by abnormal and complex electrical excitation waves in the heart. Ventricular fibrillation is a fatal condition that can lead to sudden cardiac death, and atrial fibrillation increases the risk of stroke due to thrombosis. Today, ablation therapy is widely used to treat fibrillation by ablating the abnormally excited area. However, although various ablation strategies have been proposed, the optimal ablation strategy has not been established. To establish an objective and effective fibrillation ablation strategy, we attempted to construct a machine learning model that selects the optimal ablation target based on the excitation pattern during fibrillation. We report the results of training a deep neural network model that selects the best ablation target based on the time series of the membrane potential distribution, which represents the excitation state of each cell, using a two-dimensional electrophysiological simulation model.

Bio-modeling and bio-simulation techniques are widely used in various research fields. In this presentation, I review the new trends of in silico modeling, tools, data sharing, and "digital twin" in the research field of cardiac arrhythmia. I also introduce some our research based on computational heart simulation and biomedical image analysis.

Although computer simulation (in silico) has been used as a method of theoretical study, it has recently been employed in medical device development.(1) At a development stage. By performing simulations of electrical defibrillation, appropriate shock waveform, electrode, etc. were found for the development of intra-cardiac defibrillator.(2) As a medical device itself. A simulator for cardiac safety pharmacology tests. Changes in action potentials and clinical electrocardiograms, and presence of arrhythmogenicity of unknown drugs can be simulated.(3) As a part of medical devise. Based on the intra-atrial electrograms together with a simulator that complements the electrophysiologic properties, realtime visualization of clinical atrial fibrillation was achieved.To resolve the technical, economic, and ethical limitations of medical devices, in silico was come to be utilized in various ways. More recently, in silico has been sought after as an explanation tool for the AI black box, and thus further expansion is expected.

In the exploratory R&D phase of mechanical circulatory support (MCS) devices, mock circulation tests are useful in reducing the cost of animal experiments. In this presentation, we will first show the mechanism by which our mock circulation system can generate fluid loads simulated different cardiac conditions, and its application to MCS devices evaluation. On the other hand, many in silico hemodynamic simulators have been reported including applications to the field of artificial organs. They are expected to be further utilized in the development of MCS devices with the recent advances in computer technology. In this report, we present the results of a basic study on the control of a ventricular assist device using a PC-based real-time biventricular hemodynamic simulator constructed with a simple electrical circuit model. We will also report on our efforts to apply the same simulation method to the improvement of a mock circulation system.

The support for industry-academia collaboration by the Young Researcher Activity Working Group is now in its third year. In this symposium, we will once again identify the points that will trigger industry-academia collaboration, and share know-how that allows academic members who are interested in industry-academia collaboration to smoothly start collaboration. We will introduce the matters that will be the starting point for industry-academia collaboration, such as public support from the government that leads to industry-academia collaboration, matching activities from industry such as equipment manufacturers and investment funds, and activities of industry-academia collaboration institutions within the university. As an example of industry-academia collaboration that we have experienced, we will introduce it based on actual experience such as surgical treatment devices development, diagnostic equipment development using image processing, and medical training system development combined with IoT technology.

Hiroshima University has developed Biodesign program in collaboration with Government of India as part of Prefectural medical-related industry cluster formation. In US and India, they have raised the solutions of "Silicon-Valley-type value chain" and "emerging-country-type innovation driven by lean-startup," respectively. Based on learning from India-Biodesign, we aim to realize frugal innovation by taking technological advantage and reliability of Japan in developing medical devices at affordable price. After launching Fellowship in 2019, we were entrusted with Local-Innovation-Support-Project for regional companies, and provided academic guidance to manufacturing companies. In 2020, COVID-19 pandemic required medical resource optimization. In order to promote medical technology (MedTech) development even under stagnant logistic situation, we proposed "Decentralized-Platform among Local-Core-Institutions" with AMED support. Dr. Ishikita set up secretariat at the National Hospital Organization, and his hospital leads the research projects. We report our experience from the viewpoint of biomedical engineering as an optimal solution promoting MedTech demonstrating resilience.

Before COVID-19 outbreak, it has been considered advantageous for medical device development to concentrate on large cities with centralized network. Advanced informatization and consolidation of manufacturing lines, convenience to regulatory process, industry-academia-government collaboration, and access to the business opportunity have increased the success rate. With the stagnation of logistics under the unprecedented COVID-19 epidemic, the medtech development process was literally paralyzed. Our team implemented a frugal innovation by proposing a decentralized medical device development platform in which rural-based core hospitals, universities and businesses bring resources together. In particular, our activities were supported by the National Hospital Organization. This initiative will be presented as one solution demonstrating resilience in the prevailing social situation of pandemic. The diversity becomes a strength in medical device development process. Hoping that our presented ecosystem will be useful as a platform for future innovators in Japan, and future activities will lead to regional revitalization.

The startup of industry-academia collaboration requires the researcher specific research trajectory, especially in young investigator. Even if the idea is original and full of potential, few people are willing to invest in a young, unknown and unproven researcher. The collaborator may need the evidence that indicates the realization of research idea. In this session, as a young investigator, I would like to share my experiences to start the industry-academia collaboration.

In general, industry-academia collaboration often starts joint research if the people in charge of the field collaborate with each other, but there are not many cases where this is a long-term initiative. However, medical device development requires a very long-term perspective, such as needs search, development, post-marketing surveillance after approval, and resolution of new clinical issues. Many of the causes of industry-academia collaboration mismatches are due to the formation of a common understanding of GOAL and the differences in various perceptions that each other has. In some cases, it may proceed without being taken. Regarding pitfalls and solutions in industry-academia collaboration, we will propose measures to facilitate the output of young researchers aiming to develop medical devices and new entrants, mainly based on corporate needs.

Separated distance is important in COVID-19 environment. Patients and medical materials like SPD are identified in near fields by bar-code and so on. Bar-code is also spreading as a identification media in medical scene. However, its near field identification is not fit to COVID-19 condition. Safety individual identification in COVID-19 condition is realized by using UHF band RFID system. UHF band RFID has large identification area. Electric magnetic safety is also kept in the RFID system. Author proposed wrist band tag using UHF band RFID. It is effective for safety identification in COVID-19 condition.

Recently, there has been an increase in the number of cases where systems using passive RFID proposed or introduced to improve operational efficiency in hospitals. In such proposals, the tag and the reader optimized for the target system are naturally selected. However, there is room for significant cost reduction through commonization of tags, readers, and antennas. At our hospital, UHF RFID tags have been introduced for blood specimen labels, and batch reading confirmation is performed. HF RFID tags are used for personal authentication and for capturing body temperature, blood pressure, blood oxygen saturation, and blood glucose levels into EMR. HF tags can be read from a distance of a few centimeters, while UHF tags can be read from several meters, depending on the wave strength. However, they cannot be read from a long distance, so common use of tags will inevitably be done with UHF tags.

In previous report, RFID tag wasn't shown disability shadows of images in X-p, RFID tag damages, exothermic reactions on clinical conditions as X-ray simple photograph, X-ray computed tomography, Magnetic Resonance Imaging, Positron Emission Tomography/computed tomography, scattered radiation of 10Mev X-ray Liniac for Radiation Therapy.From this result, RFID became clear to use as patient name wristband in department of radiology.This time, RFID tag was considered to be suitable for Patient Authentication System, about a characteristic of patient behavior, a facility, an authentication method, and an infectious disease control measures.As a result, it is suitable for inpatient and not for outpatient. And it is problem how to provide with present Bar code authentication system and RFID authentication system in a transition period.

In Japan, an upper limit for overtime work is set by law and the reduction of overtime work has become an issue. A survey on nurses overtime work has found that many nurses work pre-shift overtime to gather patient information before the commencement of their shifts. We aimed to clarify what kind of information-seeking behavior nurses are taking from electronic health record.First, we conducted a questionnaire survey on patient information collected before work.Then, we recorded the electronic health record screen on which nurses gazes were presented using an eye tracker and analyzed the recorded images.

Automating care recording performed by nurses or nursing staffs is a critical issue in reforming work styles.To solve this issue, the author devised and registered a utility model of a system in which an IC chip is embedded in a pressure-dispersion mattress and the direction of use can be read and recorded in the information terminal. However, daily life care is so broad that it is not practical to discuss every aspect of it. Thus we are going to propose a method of analyzing existing records and automating the process by specializing in the contents of records that have high frequency.

In many phenomena of biological systems, a minority of cells act on the entire multicellular system causing drastic changes in the system. To understand the mechanisms underlying such phenomena, it is essential to observe the spatiotemporal dynamics of a huge population of cells at sub-cellular resolution. We have been developing a "trans-scale scope" to realize cellular imaging in an over-one-centimeter field-of-view (FOV) beyond the limitation of conventional microscopes. We demonstrated its ability of time-lapse imaging of multicellular system with capturing the dynamics of 10^5-10^6 cells in the system in a single FOV. Zooming in at any position in the whole image, one can know the distribution and dynamics of the cells in the local region. It has been applied to dynamic imaging of calcium ions in HeLa cells and cyclic-adenosine-monophosphate in Dictyostelium discoideum, and successfully detected less than 0.01% of rare cells and observed multicellular events induced by these cells.

Rotating spirals are typical dynamics in signal relaying systems such as neuronal seizures and cardiac fibrillations. Although properties of generated spirals have been well studied, mechanisms in their spontaneous formation have been long elusive. We here investigated the development of social amoeba, Dictyostelium discoideum, that self-organizes spiral waves of intercellular communications from a non-signaling initial state. Imaging of signaling dynamics in ~130,000 cells identified essential features to initiate, select, and maintain the spiral wave where so-called reentry, a classical concept for the spiral formation in cardiac fibrillation, played a role. Experimental and computational analysis revealed that the initiation of reentry and transition to spiral was collectively driven by anisotropic and graded growth of the signaling ability developed by repeated activities of a few pacemakers.

Neurons of the mammalian nervous systems are highly diverse in their development, structure and function. In the present study, we aim to investigate the molecular pathophysiology of brain disorders by developing highly scalable and high-speed imaging system (block-FAce Serial microscopy Tomography, FAST) and developing animal disease models and iPS cell-derived neurons established from patients. For this aim, we are particularly interested in identifying "brain singularity biology (e.g., cellular and circuit mechanisms)" through unbiased and hypothesis-free approaches using whole-brain activation mapping coupled with machine learning. In this symposium, we will introduce our recent progress and discuss the directions of future research that would contribute to a better understanding of the brain systems as well as brain disorders.

Neurodegenerative diseases including Alzheimer's disease (AD) are common causes of death in developed countries. Neurofibrillary tangles composed of hyperphosphorylated tau proteins are one of pathological hallmarks of neurodegenerative diseases. Neurofibrillary lesions strongly corelated with cognitive deficits in neurodegenerative diseases. Recent advance of in vivo imaging techniques has opened a window to capture a real time event during brain aging. Our group recently established the positron emission tomography (PET) imaging of tau lesions using [18F]PM-PBB3 PET tracer to diagnose not only AD also non-AD tauopathies (e.g., Progressive supranuclear palsy, Corticobasal degeneration, and Chronic traumatic encephalopathy). In addition to clinical research, this tracer is a feasible to visualize tau pathologies in mouse models of tauopathy. Therefore, tau PET imaging is a translatable research tool between human and mouse tauopathies. Currently, investigating early detection of tauopathies during a transition from physiological tau proteins to pathological tau aggregates is one of our research achievements.

This talk presents our recent progress in the EEG/fNIRS hyperscanning studies, focusing on the within-brain and across-brains network during social communications. A benefit of using EEG/fNIRS in communication study is that participants are able to naturally interact under real-world settings. First, we show that the eye-to-eye experiment as a nonverbal communication experiment, in which a dyad gazed into either the partner's live eyes or their picture eyes. The eye contact with live partner modulated both within-brain and across-brains effective connectivity originated from the dorsolateral prefrontal cortex compared to eye contact with a face picture. Second, our verbal communication study revealed a bidirectional effective connectivity between motor and sensory language areas in a listener's brain during dialogue but not during monologue conditions. Elucidating the neural basis of social communication has the potential to establish biomedical applications such as assessment and assistance of social communication for people with autistic spectrum disorders.

Although the role of parent-child interaction has been intensively studied, these studies have mainly conducted by observations of dyadic behavior. In recent years, hyperscanning research which is done by measuring electrical activity or blood flow changes in each brain have raised expectations that they can elucidate the neural basis of parent-child relationships. The author's research group constructed an hyperscanning MEG system by connecting and synchronizing the child-sized MEG and the normal-sized MEG in the same shielded room. MEG, which have excellent temporal and spatial resolution, enable us to measure brain functions in real time, and to explore the neural basis of behavioral or emotional synchronization and turn-taking through audiovisual parent-child interaction. In this symposium, we will introduce the studies using this hyperscanning MEG system.

The purpose of this study was to investigate the brain activity of two people who were face-to-face with each other. In this study, we used a Dual MEG system, in which two magnetoencephalographies are connected by an optical fiber. Total 22 subjects for whom data were available. Subjects sat in a face-to-face position and watched real-time images (R) and recorded images (S:simulated) of the other person's face for 80 times. The subjects judged whether the video was R or S. Event-related synchronization and desynchronization of theta were calculated. We conducted an analysis of variance by site x video condition on trials in which the participants were unaware of the presence of the opponent (judged as S).The results showed a main effect of site (p=0.0080) and a main effect of video (p=0.0037). In particular, we found synchronization in S and desynchronization in R, in the right inferior frontal region.

The neural basis of social cognition and interaction in human was frequently explored using a neuroimaging technique such as functional magnetic resonance imaging. Recent brand-new neuroimaging technique focusing on the sharing information is the hyperscanning neuroimaging: recording two (or more) brains simultaneously during social interaction. In the present paper, we will introduce author's previous hyperscanning fMRI studies.