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Biological Function Engineering (Kobayashi Lab)

We are engaged in research to explore the remarkable functions possessed by living things and to apply this knowledge to the leading edge of electrical and electronic engineering. We are particularly focusing on the human central nervous system. By non-invasively measuring, analyzing, and imaging this system, we can explore the sophisticated mechanisms employed by the brain. In addition, we are investigating the human visual system and other sensory functions, memory, perception, and consciousness as key research topics, with a view to potential engineering applications.

Based mainly on the non-invasive measurement techniques, such as functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and electroencephalography (EEG), and on the measurement of behavioral psychophysical data of reaction time and eye movement, we are focusing on comprehensive brain function research that combines computational and theoretical approaches. In parallel with this, we are developing integrated measurement techniques and new inverse analysis methods. We are simultaneously pursuing fundamental research into measurement and analysis methods, to promote the development of high-precision numerical computation techniques to analyze electromagnetic fields generated by or applied to living things.

In addition, we are collaborating with the Graduate School of Medicine on research into bio-imaging and brain-machine-interfaces for people afflicted by sensory functions such as visual and auditory systems and motor function disabilities caused by illness or accident, with the aim of making a contribution to engineering for medical care and welfare.

Furthermore, as a member of the "Cutting-edge Techno Hub for High-order Bio-imaging" (a joint venture between Kyoto University and Canon, Inc.), we are tackling development of supersensitive optical pumping atomic magnetometers, for the purpose of promoting medical care innovations to promote faster diagnosis of illnesses and more effective preventive treatment.

Academic Staff

Tetsuo KOBAYASHI

Tetsuo KOBAYASHIProfessor (Graduate School of Engineering)

Research Interests

Biomedical engineering, functional neuroimaging, bio-signal processing, cognitive neuroscience

Contacts

Katsura Campus A1-219
TEL: +81-75-383-2228
FAX: +81-75-383-2228
E-mail: kobayashi.tetsuo.2c@kyoto-u.ac.jp
http://researchmap.jp/tetsuo-kobayashi/?lang=english

Shoji HAMADA

Shoji HAMADAAssociate Professor (Graduate School of Engineering)

Research Interests

Contacts

TEL: +81-75-383-2230
FAX: +81-75-383-2230
E-mail: shamada@kuee.kyoto-u.ac.jp

Takenori OIDA

Takenori OIDAAssistant Professor (Graduate School of Engineering)

Research Interests

  • Biomedical engineering
  • Magnetic resonance imaging (MRI)
  • Diffusion tensor imaging (DTI)
  • functional MRI (fMRI)

Contacts

Katsura Campus A1-215
TEL: +81-75-383-2259
FAX: +81-75-383-2259
E-mail: oida@kuee.kyoto-u.ac.jp

Yosuke ITO

Yosuke ITOAssistant Professor (Graduate School of Engineering)

Research Interests

Biomedical engineering, Optically pumped atomic magnetometer

Contacts

Katsura Campus A1-215
TEL: +81-75-383-2259
FAX: +81-75-383-2259
E-mail: yito@kuee.kyoto-u.ac.jp
http://researchmap.jp/yosuke_ito/?lang=english

Introduction to R&D Topics

Non-invasive neuroimaging of higher brain functions

In addition to having an extensive knowledge of neuroscience, physics, chemistry, information science, and cognitive science, understanding the operation of the brain requires understanding and developing engineering techniques in measurement technology, imaging technology, and signal processing technology. Of these, non-invasive measurement techniques that do not damage the brain are particularly essential for investigating human brain functions.

In this lab, we are collaborating with Kyoto University's Graduate School of Medicine to make use of non-invasive measurement and imaging equipments, including 1.5 T and 3.0 T MRI systems, a 306-channel MEG system, as well as a high-resolution EEG system.

Functional MRI: Neural activity in the brain is accompanied by relaxation of the arterioles, and an increase in the blood flow in the blood vessels in the activated parts of the brain results in a decrease in the deoxygenated hemoglobin concentration in the blood. This increases the transverse relaxation time of protons (hydrogen nuclei), which increases the intensity of a magnetic resonance signal. Such a signal is known as a blood oxygenation level dependent (BOLD) signal. fMRI is a technology for measuring brain functions by imaging BOLD signals. Although other (non-BOLD) fMRI devices have been trialed, most fMRI devices are still based on BOLD signals.

MEG: When neural activity occurs, the electrical current flows inside the dendrite of the pyramidal cells in the cerebral cortex and generates very tiny magnetic field — approximately 100 million times weaker than the earth's magnetic field. In the 1960s, the invention of the SQUID — a supersensitive magnetic field detector utilizing the quantum interference effect inside a superconducting ring, such as a Josephson junction — for the first time made it possible to measure such tiny magnetic fields. A brain magnetic field measured using a SQUID is known as a magnetoencephalogram (MEG). From the magnetic field distribution measured in the vicinity of the scalp, by performing inverse analysis it is possible to estimate with high precision which parts of the brain are undergoing neural activity.

Further reference:
[1] Furutani, Kobayashi, Araki, "Biomedical Treatment Applications of Measurement and Control Technologies," Measurement and Control Vol. 43, No. 3, pp. 214-219 (2004)

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Empirical research on brain mechanisms of visual perception and consciousness

The processes within the brain associated with visual awareness, i.e., the noticing or understanding of significant information from a varied mass of raw visual data, has become an important research topic in the field of cognitive science in recent years. The elucidation of visual awareness mechanisms is expected not only to contribute to the advancement of neuroscience, but also to provide valuable knowledge for various practical applications in a variety of fields, such as biomedical engineering and information science.

One psychological phenomenon that is of interest in research on visual awareness is that of "multistable perceptions." In multistable perceptions an observer who is presented with an unchanging visual stimulus experiences two or three different percepts alternately and repetitively. This provides a very easy-to-understand objective phenomenon for an empirical investigation to try to determine the kind of mechanism in the brain accounts for what is seen or noticed (i.e., for visual awareness and consciousness).

In this lab, we are investigating brain mechanisms of multistable perceptions, such as binocular rivalry and mobile ambiguous figures, by applying non-invasive neuroimaging techniques, eye movement measurements, and neural network modeling methods.

Further reference:
[1] Tetsuo Kobayashi: "Explore the riddle of Consciousness from vision," Medicine of the Brain and Mind, Vol. 13, No. 4, pp. 403-410 (2002)
[2] Tetsuo Kobayashi: "Binocular Rivalry," Cognitive Neuroscience, Vol. 7, No. 1, pp. 44-49 (2005)

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Advancement of numerical electrical field computation techniques and analysis of induction fields in living things

We are conducting numerical computations of induction fields and current resulting from low-frequency electromagnetic fields using the boundary element method (BEM) and surface charge method (SCM), which apply the fast multipole method (FMM). BEM and SCM are only applied to unknown values of physical quantities on the boundary surface between media, so they have the advantage that when D represents the number of divisions per each dimension of the system, the number of unknowns in the case of a three-dimensional analysis, N, is no more than O (D2). Furthermore, the adoption of FMM as a solution for O(N), enables a high-speed, high-capacity electric field computation technique for O(N) = O(D2) to be obtained.

Exploiting this advantage, large-scale, complex-shaped systems can be analyzed, and in the case of Laplace field analysis, better solutions can be found than with FEM or FDTD.

As background to this research, we are conducting electric-field computations of large-scale systems including the human body and large-scale complex tissue in the human body. As an example, the results of computing the induction field distribution (N = 413931, No. of terminals = 2020) around a model of the bronchial tubes resulting from a uniform alternating magnetic field (50 Hz, 1_T) are shown below.

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