Yoichi MIYAWAKI
| Department of Informatics | Professor |
| Cluster I (Informatics and Computer Engineering) | Professor |
| Department of Mechanical and Intelligent Systems Engineering | Professor |
| Cluster II (Emerging Multi-interdisciplinary Engineering) | Professor |
| Center for Neuroscience and Biomedical Engineering | Professor |
| Creative Entertainment Research and Education Center | Professor |
Researcher Information
Degree
Research Keyword
Field Of Study
Career
- Sep. 2018
National Institute of Mental Health, National Institutes of Health, Section on Functional Imaging Methods, Laboratory of Brain and Cognition, Special Volunteer - 01 Oct. 2017
Japan Science and Technology Agency, PRESTO Researcher - 01 Mar. 2017
Graduate School of Informatics and Engineering, The University of Electro-Communications, Professor - 01 Mar. 2012 - 28 Feb. 2017
Center for Frontier Science and Engineering, The University of Electro-Communications, Associate Professor - 01 Apr. 2006 - 29 Feb. 2012
NICT/ATR Computation Neuroscience Laboratories, Researcher - 01 Apr. 2005 - 31 Mar. 2006
RIKEN Brain Science Institute, Laboratory for Mathematical Neuroscience, Researcher - 01 Apr. 2004 - 31 Mar. 2005
Japan Science and Technology Agency, PRESTO group member (researcher) - 01 Apr. 2001 - 31 Mar. 2004
RIKEN Brain Science Institute, Laboratory for Advanced Brain Signal Processing, Special Postdoctroal Researcher
Educational Background
Research Activity Information
Award
Paper
- Suppression of information spreading in MEG source estimation using a functionally-structured Bayesian approach.
Kai Miyazaki; Shun Nirasawa; Naoki Ishibashi; Kazuaki Akamatsu; Okito Yamashita; Yoichi Miyawaki
NeuroImage, 333, 121934-121934, Jun. 2026, True, Magnetoencephalography (MEG) is a noninvasive method that can measure human brain activity with high temporal resolution. However, the spatial resolution of MEG is limited because MEG signals are recorded by sensors located outside the head. Although MEG source estimation overcomes this problem to some extent, the combination of MEG source estimation and multivariate analysis results in "information spreading", where significant predictions are observed in brain areas outside the true signal source location. In this study, we examine a Bayesian estimation approach that incorporates functional structure of the human brain in order to explore whether both source estimation accuracy and suppression of information spreading can be improved simultaneously. We compare the performance of the proposed model with simulated data generated under various signal-to-noise ratio conditions. The results show that the functionally-structured Bayesian model achieves source estimation accuracy that is better than that of conventional source estimation models. Additionally, the comparison of information spreading among the models reveals that our model outperforms the conventional ones. These results suggest that information spreading in the MEG source estimation can be suppressed while maintaining high source estimation accuracy.
Scientific journal, English - Acquisition and processing methods of whole-brain layer-fMRI VASO and BOLD: The Kenshu dataset.
Kenshu Koiso; Anna K Müller; Kazuaki Akamatsu; Sebastian Dresbach; Christopher J Wiggins; Omer Faruk Gulban; Rainer Goebel; Yoichi Miyawaki; Benedikt A Poser; Laurentius Huber
Aperture neuro, 3, Sep. 2023, True, Cortical depth-dependent functional magnetic resonance image (fMRI), also known as layer-fMRI, has the potential to capture directional neural information flow of brain computations within and across large-scale cortical brain networks. E.g., layer-fMRI can differentiate feedforward and feedback cortical input in hierarchically organized brain networks. Recent advancements in 3D-EPI sampling approaches and MR contrast generation strategies have allowed proof-of-principle studies showing that layer-fMRI can provide sufficient data quality for capturing laminar changes in functional connectivity. These studies have however not shown how reliable the signal is and how repeatable the respective results are. It is especially unclear whether whole-brain layer-fMRI functional connectivity protocols are widely applicable across common neuroscience-driven analysis approaches. Moreover, there are no established preprocessing fMRI methods that are optimized to work for whole-brain layer-fMRI datasets. In this work, we aimed to serve the field of layer-fMRI and build tools for future routine whole-brain layer-fMRI in application-based neuroscience research. We have developed publicly available sequences, acquisition protocols, and processing pipelines for whole-brain layer-fMRI. These protocols are validated across 60 hours of scanning in nine participants. Specifically, we identified and exploited methodological advancements for maximizing tSNR efficiency and test-retest reliability. We are sharing an extensive multi-modal whole-brain layer-fMRI dataset (20 scan hours of movie-watching in a single participant) for the purpose of benchmarking future method developments: The Kenshu dataset. With this dataset, we are also exemplifying the usefulness of whole brain layer-fMRI for commonly applied analysis approaches in modern cognitive neuroscience fMRI studies. This includes connectivity analyses, representational similarity matrix estimations, general linear model analyses, principal component analysis clustering, etc. We believe that this work paves the road for future routine measurements of directional functional connectivity across the entire brain.
Scientific journal, English - Spatiotemporal bias of the human gaze toward hierarchical visual features during natural scene viewing.
Kazuaki Akamatsu; Tomohiro Nishino; Yoichi Miyawaki
Scientific reports, 13, 1, 8104-8104, 18 May 2023, True, The human gaze is directed at various locations from moment to moment in acquiring information necessary to recognize the external environment at the fine resolution of foveal vision. Previous studies showed that the human gaze is attracted to particular locations in the visual field at a particular time, but it remains unclear what visual features produce such spatiotemporal bias. In this study, we used a deep convolutional neural network model to extract hierarchical visual features from natural scene images and evaluated how much the human gaze is attracted to the visual features in space and time. Eye movement measurement and visual feature analysis using the deep convolutional neural network model showed that the gaze was more strongly attracted to spatial locations containing higher-order visual features than to locations containing lower-order visual features or to locations predicted by conventional saliency. Analysis of the time course of gaze attraction revealed that the bias to higher-order visual features was prominent within a short period after the beginning of observation of the natural scene images. These results demonstrate that higher-order visual features are a strong gaze attractor in both space and time, suggesting that the human visual system uses foveal vision resources to extract information from higher-order visual features with higher spatiotemporal priority.
Scientific journal, English - Bodily ownership of an independent supernumerary limb: an exploratory study.
Kohei Umezawa; Yuta Suzuki; Gowrishankar Ganesh; Yoichi Miyawaki
Scientific reports, 12, 1, 2339-2339, 14 Feb. 2022, True, Can our brain perceive a sense of ownership towards an independent supernumerary limb; one that can be moved independently of any other limb and provides its own independent movement feedback? Following the rubber-hand illusion experiment, a plethora of studies have shown that the human representation of "self" is very plastic. But previous studies have almost exclusively investigated ownership towards "substitute" artificial limbs, which are controlled by the movements of a real limb and/or limbs from which non-visual sensory feedback is provided on an existing limb. Here, to investigate whether the human brain can own an independent artificial limb, we first developed a novel independent robotic "sixth finger." We allowed participants to train using the finger and examined whether it induced changes in the body representation using behavioral as well as cognitive measures. Our results suggest that unlike a substitute artificial limb (like in the rubber hand experiment), it is more difficult for humans to perceive a sense of ownership towards an independent limb. However, ownership does seem possible, as we observed clear tendencies of changes in the body representation that correlated with the cognitive reports of the sense of ownership. Our results provide the first evidence to show that an independent supernumerary limb can be embodied by humans.
Scientific journal, English - Information spreading by a combination of MEG source estimation and multivariate pattern classification
Masashi Sato; Okito Yamashita; Masa-aki Sato; Yoichi Miyawaki
PLoS ONE, Public Library of Science, 13, 6, e0198806, 01 Jun. 2018, True
Scientific journal, English - 触覚刺激時における第一次視覚野の活動と情報表現の解析
野崎 恵; 中谷 駿; 衞藤 祥太; 高橋 陽香; 青木 直哉; 角谷 基文; 北田 亮; 定藤 規弘; 神谷 之康; 宮脇 陽一
Vision, 日本視覚学会, 29, 1, 34-34, Jan. 2017, Peer-reviwed
Japanese - Multivariate Analysis of Magnetic Resonance Imaging Signals of the Human Brain
Yoichi Miyawaki
CURRENT TOPICS IN MEDICINAL CHEMISTRY, 16, 24, 2685-2693, 2016, Peer-reviwed, Invited, True
Scientific journal, English - Inter-subject neural code converter for visual image representation
Kentaro Yamada; Yoichi Miyawaki; Yukiyasu Kamitani
NEUROIMAGE, 113, 289-297, Jun. 2015, Peer-reviwed, True
Scientific journal, English - 機能的磁気共鳴画像法を用いた神経コードの解読
宮脇陽一
システム/制御/情報, Institute of Systems, Control and Information Engineers, 59, 9, 353-359, 2015, Peer-reviwed
Scientific journal, Japanese - Relationship between timing of object category representation and the level of category abstraction in the human visual cortex
Masashi Sato; Yoichi Miyawaki
I-PERCEPTION, 5, 4, 295-295, 2014, Peer-reviwed
International conference proceedings, English - Neural Decoding of Visual Imagery During Sleep
T. Horikawa; M. Tamaki; Y. Miyawaki; Y. Kamitani
SCIENCE, 340, 6132, 639-642, May 2013, Peer-reviwed
Scientific journal, English - Modular Encoding and Decoding Models Derived from Bayesian Canonical Correlation Analysis
Yusuke Fujiwara; Yoichi Miyawaki; Yukiyasu Kamitani
NEURAL COMPUTATION, 25, 4, 979-1005, Apr. 2013, Peer-reviwed, True
Scientific journal, English - Spike suppression in a local cortical circuit induced by transcranial magnetic stimulation
Yoichi Miyawaki; Takashi Shinozaki; Masato Okada
JOURNAL OF COMPUTATIONAL NEUROSCIENCE, 33, 2, 405-419, Oct. 2012, Peer-reviwed, True
Scientific journal, English - 脳情報デコーディング技術とその応用
宮脇陽一; 神谷之康
計測と制御, 50, 10, 888-894, 2011
Scientific journal, Japanese - Influence of Coherence Between Multiple Cortical Columns on Alpha Rhythm: A Computational Modeling Study
Yasushi Naruse; Ayumu Matani; Yoichi Miyawaki; Masato Okada
HUMAN BRAIN MAPPING, 31, 5, 703-715, May 2010, Peer-reviwed, True
Scientific journal, English - Estimating image bases for visual image reconstruction from human brain activity
Yusuke Fujiwara; Yoichi Miyawaki; Yukiyasu Kamitani
Advances in Neural Information Processing Systems, 22, 576-584, 2010, Peer-reviwed
Scientific journal, English - Visual image reconstruction from human brain activity: A modular decoding approach
Yoichi Miyawaki; Hajime Uchida; Okito Yamashita; Masa-aki Sato; Yusuke Morito; Hiroki C. Tanabe; Norihiro Sadato; Yukiyasu Kamitani
INTERNATIONAL WORKSHOP ON STATISTICAL-MECHANICAL INFORMATICS 2009 (IW-SMI 2009), 197, 2009, Peer-reviwed
International conference proceedings, English - Automatic extraction of visual image bases from fMRI response patterns
Yusuke Fujiwara; Yoichi Miyawaki; Yukiyasu Kamitani
NEUROSCIENCE RESEARCH, 65, S108-S108, 2009, Peer-reviwed
English - Visual Image Reconstruction from Human Brain Activity using a Combination of Multiscale Local Image Decoders
Yoichi Miyawaki; Hajime Uchida; Okito Yamashita; Masa-aki Sato; Yusuke Morito; Hiroki C. Tanabe; Norihiro Sadato; Yukiyasu Kamitani
NEURON, 60, 5, 915-929, Dec. 2008, Peer-reviwed, True
Scientific journal, English - Rate reduction for associative memory model in Hodgkin-Huxley-type network
Masafumi Oizumi; Yoichi Miyawaki; Masato Okada
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 77, 6, 064802:1-6, Jun. 2008, Peer-reviwed
Scientific journal, English - Decoding heading directions from human brain activity(Summary of Awarded Presentation at the 26th Annual Meeting)
SHIGEMASU Hiroaki; MIYAWAKI Yoichi; KAMITANI Yukiyasu; KITAZAKI Michiteru
The Japanese Journal of Psychonomic Science, The Japanese Psychonomic Society, 27, 1, 121-122, 2008, We investigated whether fMRI-derived cortical activity patterns induced by optic flow can predict the direction of heading. The cortical activity from hMT+, which is related to motion perception, led to good predictions. Focusing on the good performance of heading perception with eye movement, we also measured the cortical activity from an optic flow with eye movement. The decoder was trained with the activity patterns without eye movement and tested on those with actual eye movements, and vice versa. hMT+ exhibited a less robust, though still relatively the best, decoding performance. These results suggest that hMT+ is involved in heading perception and coding head-centric motion along with compensating for extra-retinal information. More generally, our study shows that decoding techniques can be used as effective tools in identifying the functions associated with cortical activity.
English - fMRIによる自己運動方向知覚の復号化(日本基礎心理学会第26回大会,大会発表要旨)
繁桝 博昭; 宮脇 陽一; 神谷 之康; 北崎 充晃
基礎心理学研究, 日本基礎心理学会, 26, 2, 220-220, 2008
Japanese - Higher order effects on rate reduction for networks of Hodgkin-Huxley neurons
Masafumi Oizumi; Yoichi Miyawaki; Masato Okada
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 76, 4, 044803:1-6, Apr. 2007, Peer-reviwed
Scientific journal, English - 経頭蓋磁気刺激による視知覚抑制の神経メカニズム
宮脇陽一
日本神経回路学会誌, 14, 1, 44-57, 2007
Scientific journal, Japanese - 川人光男 ASCONE 2006 特別講義: 小脳の学習理論，LTD のシステムバイオロジーモデル，そして操作脳科学へ
田中宏和; 宮脇陽一
日本神経回路学会誌, Japanese Neural Network Society, 14, 2, 104-140, 2007, Autumn School for Computational Neuroscience 2006 (ASCONE 2006) が2006年11月23日 (木) ～2006年11月26日 (日) 伊豆高原ルネッサ赤沢にて開催された. 本稿は, ATR脳情報研究所所長の川人光男先生の招待講演の講義録である.
Scientific journal, Japanese - Mechanisms of spike inhibition in a cortical network induced by transcranial magnetic stimulation
Y Miyawaki; M Okada
NEUROCOMPUTING, 65, 463-468, Jun. 2005, Peer-reviwed
Scientific journal, English - A network model of perceptual suppression induced by transcranial magnetic stimulation
Y Miyawaki; M Okada
NEURAL COMPUTATION, 16, 2, 309-331, Feb. 2004, Peer-reviwed, True
Scientific journal, English - Mechanism of neural interference by transcranial magnetic stimulation: network or single neuron?
Y Miyawaki; M Okada
ADVANCES IN NEURAL INFORMATION PROCESSING SYSTEMS 16, 16, 1295-1302, 2004, Peer-reviwed
International conference proceedings, English - Unconscious adaptation: a new illusion of depth induced by stimulus features without depth
R Hayashi; Y Miyawaki; T Maeda; S Tachi
VISION RESEARCH, 43, 26, 2773-2782, Dec. 2003, Peer-reviwed, True
Scientific journal, English - The time course of stereopsis: The delayed VEP component correlate of figure-ground processes
Yoichi Miyawaki; Ryusuke Hayashi; Taro Maeda; Susumu Tachi
Electronics and Communications in Japan, Part II: Electronics (English translation of Denshi Tsushin Gakkai Ronbunshi), 86, 11, 72-86, Nov. 2003
Scientific journal - A network model of inhibitory effects induced by transcranial magnetic stimulation
Y Miyawaki; M Okada
NEUROCOMPUTING, 52-4, 837-842, Jun. 2003, Peer-reviwed
Scientific journal, English - Probing the neural mechanism of binocular information processing with VEPs
Ryusuke Hayashi; Yoichi Miyawaki; Taro Maeda; Susumu Tachi
Electronics and Communications in Japan, Part II: Electronics (English translation of Denshi Tsushin Gakkai Ronbunshi), 86, 3, 47-60, Mar. 2003
Scientific journal - Computational model of transcranial magnetic stimulation: Temporal property and subthreshold prolongation of visual suppression induced by neural population
Yoichi Miyawaki; Masato Okada
Journal of Vision, 3, 9, 749, 2003, Peer-reviwed
Scientific journal, English - 立体視過程の時間推移-遅延性誘発電位と図地分離過程-
宮脇陽一; 林隆介; 前田太郎; 舘暲
電子情報通信学会論文誌, J85-D-II, 2, 337-350, 2002, Peer-reviwed
Scientific journal, Japanese - 視覚誘発電位計測に基づく両眼視覚情報処理過程の解析
林隆介; 宮脇陽一; 前田太郎; 舘暲
電子情報通信学会論文誌, J84-D-II, 3, 559-570, 2001, Peer-reviwed
Scientific journal, Japanese - Visual evoked potentials to dynamic random-dot stereograms - the influence of visual field location, disparity and interocular correlation on latency
R. Hayashi; Y. Miyawaki; T. Maeda; S. Tachi
Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, 1, 425, 1999
International conference proceedings - 奥行き知覚時の視覚誘発電位における２峰性波の性質
宮脇陽一; 柳田康幸; 前田太郎; 舘暲
電子情報通信学会論文誌, The Institute of Electronics, Information and Communication Engineers, J82-D-II, 5, 961-972, 1999, Peer-reviwed, 人間の立体知覚過程の客観的理解へ向け、非侵襲かつ高時間分解能という特徴をもつ視覚誘発電位計測に着目した。視差を含む立体図形刺激としてRandom-Dot Stereogramを被験者に提示した場合、後頭葉に潜時約200ms前後の陰性電位が発生することがよく知られているが、従来これらの実験は比較的狭い視覚野での刺激提示がほとんどであった。そこで、本論文では約40ﾟ程度の広視野での立体刺激提示を行い、その結果、従来には報告されていなかった潜時約180msと約280msの2峰性の陰性電位（N180及びN280)を再現性高く確認した。更に、立体図形の視差と形状に関する条件を変化させていくつかの実験を行ったところ、N180成分は比較的低次過程からの影響が強く、対してN280成分は形状や奥行の認知にかかわる高次過程からの影響が強く現れている可能性があることが示唆された。更に、このN280成分の振幅変化について解析を行ったところ、中心視における視差検出の優位性が示唆された。
Scientific journal, Japanese
MISC
- 触覚刺激弁別課題時における複数脳領域における活動と情報表現の相互作用
佐藤海渡; 野崎恵; 中谷駿; 高橋陽香; 角谷基文; 北田亮; 定藤規弘; 定藤規弘; 神谷之康; 神谷之康; 宮脇陽一
2022, 日本神経化学会大会抄録集(Web), 65th, 202302279388204112 - Analysis of temporal change of astrocyte morphology under hypoxial adaptation using higher-order image features
西野 智博; 田中 草介; 新タ 雅啓; 須貸 拓馬; 正本 和人; 宮脇 陽一
電子情報通信学会, 13 Mar. 2017, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 521, 159-164, Japanese, 0913-5685, 40021163926, AN10091178 - Image classification of astrocytes for pre- and post-hypoxia adaptation using deep convolutional neural network
田中 草介; 新タ 雅啓; 正本 和人; 宮脇 陽一
電子情報通信学会, 22 Mar. 2016, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 514, 125-130, Japanese, 0913-5685, 40020791509, AN10091178 - 触覚刺激時におけるヒト視覚野の活動と触覚情報表現
中谷駿; 高橋陽香; 高橋陽香; 青木直哉; 青木直哉; 北田亮; 北田亮; 定藤規弘; 定藤規弘; 神谷之康; 神谷之康; 宮脇陽一
02 Sep. 2015, 日本神経回路学会全国大会講演論文集, 25th, 6-7, Japanese, 201502206094907257 - Temporal relationship between object category representation and the level of category abstraction in the human visual cortex
SATO Masashi; MIYAWAKI Yoichi
Object categories can be hierarchically ordered from abstract to concrete levels. Previous studies showed that the corresponding hierarchy can be found in spatial patterns of human brain activity. However, it remains unclear when each object category is represented in human brain activity patterns and whether it is also ordered in a hierarchical manner in the time domain according to the level of category abstraction. In this study, we measured human brain activity patterns in high temporal resolution using magnetoencephalography while subjects observed object images selected from multiple categories. We estimated cortical current distributions and then applied multivariate pattern analyses to estimate the timings at which each object category is represented in brain activity patterns. Our present results showed no significant difference in latency of object category representation along the level of category abstraction, suggesting possibility that object category information is represented at similar latency in the human brain irrespective of their levels of abstraction., The Institute of Electronics, Information and Communication Engineers, 17 Mar. 2014, IEICE technical report. Neurocomputing, 113, 500, 227-232, Japanese, 0913-5685, 110009862364, AN10091178 - Visual image reconstruction from human brain activity
MIYAWAKI Yoichi; UCHIDA Hajime; YAMASHITA Okito; SATO Masa-aki; MORITO Yusuke; TANABE Hiroki; SADATO Norihiro; KAMITANI Yukiyasu
Recent functional magnetic resonance imaging (fMRI) studies have shown that visual stimuli that a subject observes can be predicted from fMRI activity patterns using machine learning techniques. However, previous approach has focused on classifying brain activity into pre-specified categories, thereby predicting only simple visual features such as orientation and motion direction, and cannot reconstruct a visual image as it is. Constraint-free visual image reconstruction is more challenging than classification, as it is impractical to specify brain activity for all possible images. Here we reconstructed visual images that subjects observe by combining local image bases of multiple scales, whose contrasts were independently predicted from fMRI activity by automatically selecting relevant voxels and exploiting their correlated patterns. The results suggest that our approach provides an effective means to read out complex perceptual states from brain activity while discovering information representation in multivoxel patterns. We also discuss about future applications of our method to prediction of arbitrary finger/limb movements from human brain activity., The Institute of Electronics, Information and Communication Engineers, 08 Jun. 2009, IEICE technical report, 109, 83, 51-56, Japanese, 0913-5685, 110007360627, AN10487237 - 脳デコーディング技術を用いた物体間,物体内奥行き知覚の処理過程の検討
繁桝博昭; 宮脇陽一; 神谷之康; 北崎充晃
日本基礎心理学会, 31 Mar. 2009, 基礎心理学研究, 27, 2, 182-183, Japanese, 0287-7651, 200902227859703913, 110007228135 - Reconstruction of visual images by combining multi-resolution local image decoders
UCHIDA Hajime; MIYAWAKI Yoichi; YAMASHITA Okito; SATO Masa-aki; TANABE Hiroki C; SADATO Norihiro; KAMITANI Yukiyasu
Recent studies have shown that human brain activity measured by functional magnetic resonance imaging (fMRI) can be decoded to predict visual perceptual parameters such as orientation and motion direction. In this study, we present methods to reconstruct arbitrary visual images from fMRI signals. The image decoder was constructed by combining local image decoders that were trained to predict the mean contrast of local image segments of multiple scales from fMRI activity patterns. We examined three methods for combining local image decoders 1) pixel representation, 2) multi-scale representation, 3) bayes estimation based on generative model for fMRI signals. These methods showed high reconstruction accuracy for arbitrary visual images. Our approach for reconstructing visual images provides a unique tool to study detailed representaion and processing in the visual cortex., The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2007, IEICE technical report. Neurocomputing, 106, 588, 79-84, Japanese, 0913-5685, 110006249030, AN10091178 - 21aWB-7 Rate Reduction for Network of Hodgkin-Huxley Neurons with Auto-correlation Type Interaction
Oizumi Masafumi; Miyawaki Yoichi; Okada Masato
The Physical Society of Japan (JPS), 28 Feb. 2007, Meeting abstracts of the Physical Society of Japan, 62, 1, 299-299, Japanese, 1342-8349, 110007191246, AA11439205 - Rate reduction for a Hodgkin-Huxley type network model with a Hebbian connection
OIZUMI Masafumi; MIYAWAKI Yoichi; OKADA Masato
We proposed a systematic reduction method from a Hodgkin-Huxley type network model to a rate network model according to Shriki et al.'s formulation [1] [2]. However, in the proposed framework, we ad hoc assumed that the threshold and gain of the f-I curve of the Hodgkin-Huxley type conductance-based model have second order dependence on the leak conductance. Here we discuss an optimal model selection with respect to the dependence of the threshold and gain on the f-I curve by making use of Akaike information criterion. We then apply our rate reduction method to the Hodgkin-Huxley type network with a Hebbian connection. We store three correlated patterns in this network and investigate the phase transition between memory state and mixed state. We show that our rate model reproduce the results of the Hodgkin-Huxley type network very well., The Institute of Electronics, Information and Communication Engineers, 18 Jan. 2007, IEICE technical report, 106, 500, 37-42, Japanese, 0913-5685, 110006204904, AN10091178 - Reconstruction of visual images from fMRI signals by combination of multi-resolution local image decoders
Yoichi Miyawaki; Hajime Uchida; Okito Yamashita; Masa-aki Sato; Hiroki C. Tanabe; Norihiro Sadato; Yukiyasu Kamitani
2007, NEUROSCIENCE RESEARCH, 58, S55-S55, English, Summary international conference, 0168-0102, WOS:000249272800321 - Multiple generators model based on neural mass model for MEG/EEG
Yasushi Naruse; Ayumu Matani; Yoichi Miyawaki; Masato Okada
2007, NEUROSCIENCE RESEARCH, 58, S215-S215, English, Summary international conference, 0168-0102, WOS:000249272801278 - 26pXD-1 Higher Order Effects on Rate Reduction for Network of Hodgkin-Huxley Neurons
Oizumi Masafumi; Miyawaki Yiochi; Okada Masato
The Physical Society of Japan (JPS), 18 Aug. 2006, Meeting abstracts of the Physical Society of Japan, 61, 2, 244-244, Japanese, 1342-8349, 110007183205, AA11439205 - Higher Order Effects on Rate Reduction for Network of Hodgkin-Huxley Neurons
OIZUMI Masafumi; MIYAWAKI Yoichi; OKADA Masato
We propose a systematic method of rate reduction for a Hodgkin-Huxley type neural network model. In this context, Shriki et al. assumed that the threshold of f-I cureve for the reduced rate model linearly depends on the leak conductance of the Hodgkin-Huxley equation, while its gain remains constant. First, we will show that they have second order dependence. Second, we show that we can naturally reduce the Hodgkin-Huxley type network with second order interaction to an analog type neural network model with higher order interaction based on this finding. Finally, we construct statistical mechanics for the Hodgkin-Huxley type network with the Mexican-hat type interaction through our rate reduction technique., The Institute of Electronics, Information and Communication Engineers, 07 Jul. 2006, IEICE technical report, 106, 163, 13-18, Japanese, 0913-5685, 110004809700, AN10091178 - 29pXH-10 Macroscopic Equations for Network of Hodgkin-Huxley Neurons
Oizumi Masafumi; Miyawaki Yoichi; Okada Masato
The Physical Society of Japan (JPS), 04 Mar. 2006, Meeting abstracts of the Physical Society of Japan, 61, 1, 308-308, Japanese, 1342-8349, 110007181352, AA11439205 - 24pYB-3 Correlation analysis of population code for orientation tuning function
Miura Keiji; Miyawaki Yoichi; Okada Masato
The Physical Society of Japan (JPS), 04 Mar. 2005, Meeting abstracts of the Physical Society of Japan, 60, 1, 272-272, Japanese, 1342-8349, 110004535184, AA11439205 - 13pTC-3 Relaxation dynamics of HH system and solvable analog neural network
MIYAWAKI Y; OKADA M
The Physical Society of Japan (JPS), 25 Aug. 2004, Meeting abstracts of the Physical Society of Japan, 59, 2, 220-220, Japanese, 1342-8349, 110002051979, AA11439205 - Neural mechanism of transcranial magnetic stimulation : spike inhibition in a recurrent cortical network
MIYAWAKI Yoishi; OKADA Masato
We propose mechanisms of neural interference induced by transcranial magnetic stimulation (TMS). TMS is widely used as a powerful and unique experimental tool to stimulate the human brain noinvasively, which typically induces inhibitory effect on the cortical functions. However, the fundamental neural mechanism of TMS-induced suppression is still unclear, even though twenty years have passed science the first TMS technique has developped. In this paper, we assume TMS as an brief perturbation that is uniformly applied onto a neural population, and computationally analyze the mechanism of TMS-induced suppression. Here, in particular, we employed a conductance-based recurrent network model exhibiting feature selectivity in the cortex. We demonstrate that the TMS-like perturbation induces sustained spike inhibition in the network without the ion channel which is necessary for spike inhibition in an isolated single neuron, suggesting that each individual neuron is not necessarily suppressed by TMS; rather, a collapse of excitatory and inhibitory input balance in the cortical network is crucial for TMS-induced suppression., The Institute of Electronics, Information and Communication Engineers, 21 May 2004, IEICE technical report. Neurocomputing, 104, 99, 55-60, English, 0913-5685, 110003234041, AN10091178 - A network model of perceptual suppression induced by transcranial magnetic stimulation
MIYAWAKI Yoichi; OKADA Masato
We studied inhibitory effects of transcranial magnetic stimulation (TMS) on neural population. TMS can affect the electromagnetic activities inside our brain with high temporal resolution and without any invasions. Due to these advantages, TMS is widely used as a powerful tool not only in cognitive neuroscience field but also as a clinical treatment. However, the neural mechanisms underlying the effect, especially in theoretical aspect, are quite unclear. In this study, we employed a simple neural population model and computationally analyzed their responses to a TMS-like brief pulsed perturbation. Applying the perturbation, the averaged network activity transiently increased, and then decreased for relatively long lasting period followed by loss of a localized activity pattern. When afferent input has a strong transient component and weak sustained component, there exists a critical latency period in which the perturbation completely suppresses the network activity. These results suggest that inhibitory effects typically observed in TMS studies can be yielded by dynamical interaction in neural population., The Institute of Electronics, Information and Communication Engineers, 11 Mar. 2002, IEICE technical report. Neurocomputing, 101, 735, 197-204, English, 0913-5685, 110003234269, AN10091178 - The illusion of depth induced by adaptation to anticorrelated RDS.
R Hayashi; Y Miyawaki; T Maeda; S Tachi
Mar. 2001, INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE, 42, 4, S503-S503, English, Summary international conference, 0146-0404, WOS:000168392102685 - The VEP component related to figure-ground processes in the time course of stereopsis.
Y Miyawaki; R Hayashi; T Maeda; S Tachi
Mar. 2001, INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE, 42, 4, S404-S404, English, Summary international conference, 0146-0404, WOS:000168392102147 - The late negative figure - ground VEP modulated by focal attention
Y. Miyawaki; R. Hayashi; T. Maeda; S. Tachi
2001, PERCEPTION, 30, 44-45, English, Summary international conference, 0301-0066, WOS:000207113100138 - Probing the time course of disparity processing with visual evoked potentials.
R Hayashi; Y Miyawaki; T Maeda; S Tachi
Mar. 2000, INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE, 41, 4, S735-S735, English, Summary international conference, 0146-0404, WOS:000086246703981 - Study of Visual Evoked Potencials with Depth Perception
MIYAWAKI Yoichi; MAEDA Taro; TACHI Susumu
04 Sep. 1997, 生体・生理工学シンポジウム論文集, 12, 301-304, Japanese, 10016712161, AN10442953 - Study of Visual Evoked Potentials with Depth Perception
MIYAWAKI Yoichi; MAEDA Taro; TACHI Susumu
We regard measurement of visual evoked potencials with depth perception as a foundamental experiment to estimate reality on a visual display of a virtual reality system. It has been known that the peak latency of the negative potencials in occipital region of human scalp evoked by stimuli including disparity was 200msec or so. Generally these experiments were carried out on the condition that stimuli were displayed in small visual field. Then we made the visual field wide as much as 40 degree and found out the two negative peaks which latency was 180msec and 280msec or so. We made some experiments to identify the main factor of these peaks, so it was estimated that the latter peak was mainly related to depth and shape perception. According to our analysises of the latter one, it resulted that foveal vision is superior to peripheral on detecting binocular disparity., The Institute of Electronics, Information and Communication Engineers, 17 Mar. 1997, IEICE technical report. ME and bio cybernetics, 96, 581, 23-30, Japanese, 110003286876, AN1001320X
Books and other publications
Courses
- Fundamental of Mechanical and Intelligent Systems Engineering
The University of Electro-Communications - Fundamentals of Measurement Engineering
The University of Electro-Communications - Human-Machine System
The University of Electro-Communications - 人間機械システム
電気通信大学 - Complex Analysis
The University of Electro-Communications - 複素関数論
電気通信大学 - 工学解析および演習
The University of Electro-Communications - 機械知能システム学専攻基礎
The University of Electro-Communications - 機械知能システム学専攻基礎
電気通信大学 - 計測工学基礎
The University of Electro-Communications - 工学解析および演習
The University of Electro-Communications - 工学解析および演習
電気通信大学 - 大学院総合コミュニケーション科学
The University of Electro-Communications - 大学院総合コミュニケーション科学
電気通信大学 - 知能機械工学専攻基礎
The University of Electro-Communications - 知能機械工学専攻基礎
電気通信大学 - 計測工学基礎
The University of Electro-Communications - 計測工学基礎
電気通信大学
Research Themes
- Study of active vision dynamics by high-spatiotemporal-resolution measurement and analysis of human brain activity
宮脇 陽一; 福永 雅喜; 山下 宙人; 柳澤 琢史
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (A), 25H01138
01 Apr. 2025 - 31 Mar. 2029 - Study on psychophysical, neural, and social acceptance of augmented body
宮脇 陽一; 北崎 充晃; 杉本 麻樹; GOWRISHANK AR.G
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Challenging Research (Pioneering), 研究期間の初年度である今年度は、主として、拡張身体の身体化、限界、最適化の３つの課題に対して、心理物理学的アプローチと脳計測的アプローチで取り組んだ。その結果、以下の成果を得た：
【心理物理学的アプローチ】構造的水準、規模的水準、表層的水準という視点で実験条件の体系化を行い、実験プラットフォームの構築を開始した。構造的水準の例として、四肢の関節が通常と逆に曲がる身体をVRアバターで構築し、それへの順応を調べた。規模的水準の例として、手足のみからなるVR透明アバターの配置を操作し、通常よりも大きいあるいは小さい身体に対する身体所有感を調べた。表層的水準として、見た目を変身するシステムを構築し、変身する際に感じる変身感を心理的に計測した。これらの結果は、拡張身体の身体化プロセスを評価するとともに、その限界に関する知見を得ることに繋がるものであった。加えて、人工指を用いた実験プラットフォームにおいては、従来研究で実施した小指側方への装着に加え、人差し指と親指の間への装着実験を開始し、両者の比較により、装着部位の最適性を評価した。さらに、人間と機械が半自律的に協調動作する身体を操作した条件で身体所有感・行為主体感がどのように変化するかを検証する為、実環境のロボットアームを協調操作する実験系を構築した。実験を通じて、操作者と機械が目的を共有しているかどうかによって、有意差が生じることを検証した． 【脳計測的アプローチ】人工指を用いた実験プラットフォームにおいて、小指側方に人工指を装着し、それに順応した場合に脳活動がどう変容するかを評価し、あわせて心理物理学的に定量化した知覚の変化量との関係を解析した。また同様の実験と解析を、人差し指と親指の間への装着した場合でも開始した。これらの結果は拡張身体の身体化に伴う脳内表現を評価し、拡張身体の最適性に関する知見を得ることに繋がるものであった。, 23K17460
30 Jun. 2023 - 31 Mar. 2026 - Exploration of latent spatio-temporal resolution of human brain activity analysis using fusion technology of ultra-high field magnetic resonance imaging and magnetoencephalography
Miyawaki Yoichi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (A), In this study, we aimed at establishing basic methodologies for analyzing neural information represented in human brain activity acquired with ultra-high-field magnetic resonance imaging (MRI) and magnetoencephalography (MEG) at high spatiotemporal resolution. The major accomplishments are as follows: (1) We developed a structured source estimation model that can reduce information spreading while maintaining source estimation accuracy. (2) We systematically evaluated the new structured source estimation model from multiple perspectives, including noise tolerance and its capacity to analyze complex brain activity patterns. (3) We performed ultrafast functional MRI (fMRI) at ultra-high magnetic field and successfully captured brain activity signals from multiple brain areas, including subcortical regions. (4) We analyzed the ultrafast fMRI signals and revealed a relationship between the distribution of venous blood and the information representation of information in the brain., 20H00600
01 Apr. 2020 - 31 Mar. 2024 - 自然光景下における視線移動と視覚的物体認識ダイナミクスの統合的研究
宮脇陽一
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (B), Principal investigator, In this study, we aimed to understand what humans preferentially look at and recognize in natural scenes consisting of various objects from a temporal perspective, and obtained the following results. (1) We found spatio-temporal prioritization of gaze toward higher-order image features by combining analysis of eye movements during observation of natural scene images and quantification of image features using a deep convolutional neural network. (2) We found that this prioritization is caused solely by image features, regardless of the meaning or context of presented images. (3) We developed a new source estimation method for measuring and analyzing magnetoencephalography signals with high spatiotemporal resolution. (4) We estimated the representation time for object image information in brain activity patterns and compared it with the latency for eye movement., 17H01755
01 Apr. 2017 - 31 Mar. 2021 - Study on high spatiotemporal resolution measurement and analysis of human brain activity using ultra-high field functional magnetic resonance imaging
Miyawaki Yoichi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Fund for the Promotion of Joint International Research (Fostering Joint International Research (A)), In this study, we aimed to establish fundamental methods for measuring and analyzing human brain activity with high spatiotemporal resolution using ultra-high-field functional MRI (7T fMRI). The main achievements were as follows: (1) In collaboration with National Institutes of Health (USA), we developed one of the world’s fastest in fMRI protocol (ultra-fast fMRI) with a sampling interval of 125 ms, (2) we succeeded in rapid decoding of visual information from the ultra-fast fMRI signals, (3) using the ultra-fast fMRI signals and decoding, we succeeded in separating signal components related to neural activity from those reflecting vascular characteristics, and (4) we expanded the project through international collaborations with several European universities and identified cortical layer-wise representation of visual information. These results contribute to achieve high spatiotemporal resolution in human brain activity measurement and analysis., 18KK0311
2019 - 2021 - 高時空間分解能脳情報解析による自然条件下での実世界認識ダイナミクスの研究
宮脇 陽一
科学技術振興機構, 戦略的な研究開発の推進/戦略的創造研究推進事業/さきがけ, 視覚的な外界の認識は、人類の生存・繁殖・文化の形成を担う重要な脳機能です。本研究では、私たちが普段生活している環境になるべく近い自然な条件下におけるヒトの行動計測と、複数の脳活動計測を併用し、得られたデータを統合的に解析する手法を研究します。これにより、現存する脳活動計測の時空間的分解能の実効的突破と、人間の実世界認識を担う神経メカニズムの解明に挑戦します。, 17939718
2017 - 2021 - 深層ニューラルネットワークを用いた細胞形態特徴抽出と疾患変異性形態特徴の可視化
宮脇陽一
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Principal investigator, 本年度は、前年度までの課題で得られた結果をもとにして、課題３であるグリア細胞の疾患変異性特徴量の可視化と応用に中心的に取り組んだ。この目標達成のために、以下の項目を実施した。 （１）グリア細胞の形状特徴量を用いた疾患状態予測と疾患変異性特徴量の同定：グリア細胞画像から抽出した特徴量のうち、どの特徴量が疾患時に大きな影響を受けるのかをスパースモデリングの手法を用いて解析し、ごく一部の特徴量からも疾患状態が予測可能であることを確認した。 （２）疾患変異性特徴量の可視化：（１）の方法で同定された特徴量に対応する画像部分がどこであるかを可視化し、形態変異に関与している細胞部位を解釈可能にすることを試みた。結果、疾患予測に重要な特徴量が局在する空間位置を、細胞画像に重ね書きして可視化する技術の開発に成功した。 （３）空間特異性の解析：疾患によって強い変化をうける特徴量がどこに局在しているかを解析した。細胞体近辺あるいはその周辺部に局在している場合などが見受けられたが、現時点では体系的に統一した傾向は見られていない。 以上の結果より、当初の研究目的であったグリア細胞の形態特徴と病態との連関を示すことに成功し、またその関係性を細胞画像上で可視化する技術の開発に成功したといえる。その一方で、細胞形態変化の特異性に統一的な解釈を与えるには至っていない。こうしたばらつきは、例えば血管との距離や皮質表面からの深さなど、細胞が位置する情報などとの関連を付加的に解析することにより吸収できる可能性もあると考えている。, 17H05285
01 Apr. 2017 - 31 Mar. 2019 - スパースモデリングを用いたヒト脳活動の高時空間分解能解析と脳情報源の同定
宮脇 陽一
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), 本年度は、昨年度までに開発・評価した手法を用いて、ヒトの実MEG信号を解析した。この目標に即し、以下の項目を順次実施した。 （１）MEG信号計測実験：提示可能な物体画像カテゴリ数を多くするため、複数の物体画像を併置して同時に提示した際の脳活動計測実験を進めることを当初計画したが、その前段階として、単一物体画像提示時のMEG信号解析の精緻化と強い再現性の確認が必要となったため、それらを優先して実施した。結果、被験者１０名での現象の確認に成功し、研究成果の論文化に向けて大きく前進した。加えて、実MEG信号の信号源推定においても情報拡散が生じるかを確認するため、レチノトピー同定実験に標準的に用いる比較的単純な視覚刺激を用いたMEG信号計測実験を実施した。 （２）神経電流分布の推定：情報拡散が少ないMEG信号源推定方法は、脳活動パターンの分類精度が低いというトレードオフの関係にあることが分かった。よって、情報拡散はある程度生じるものの信号源位置の同定精度と脳活動パターンの分類精度において好成績を収めるfMRI信号による制約付きMEG信号源推定法を、実データの解析において中心的に用いることにした。 （３）神経電流分布に表現される画像情報の時間分解解析：以上の方法を用いて、推定したMEG信号源パターンから提示した物体画像カテゴリを時々刻々予測する統計モデル（デコーダ）を機械学習し、物体画像カテゴリの情報が神経活動に表現された時刻を様々な物体カテゴリに対して幅広く推定した。この手法と併用し、情報拡散の影響を低減させる可能性のあるsignal leakage reduction法の適用を試みた。また（１）のレチノトピー同定実験の視覚刺激に対するMEG信号源推定の時間分解解析の結果から、実MEG信号の解析においても情報拡散が生じている可能性が高いことを示唆することに成功した。, 16H01541
01 Apr. 2016 - 31 Mar. 2018 - 人工手指を自分の手指のように動かす：ヒト脳活動を用いた人工手指の自然な学習
Gowrishankar Ganesh
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, National Institute of Advanced Industrial Science and Technology, Grant-in-Aid for Challenging Exploratory Research, In this project we aimed to understand the key requirements for enabling a human brain to learn and use an artificial robot limb as naturally as one’s own limb? For this purpose: 1)We utilized psychophysical experiments to understand what characteristics of an artificial entity would make our brain feel as the entity is part of our self. 2)We developed a robotic extra (sixth) finger/ feedback system that can be controlled using neural signals and utilized it in experiments to test results in (1). 3)We developed a technique to isolate and verify the ‘free neural activity’ in the brain, that can be used to control artificial limbs. 5)Finally, though not initially in the project, we extended the results in (1) to define, for the first time, ‘embodiment’ by robots, and enable human-like tool cognition in robots., 15K12623
01 Apr. 2015 - 31 Mar. 2017 - 脳情報復号化技術を用いた視覚野における触覚情報表現の解明
宮脇陽一
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), Principal investigator, Previous studies suggest that the primary visual cortex can be activated by touching tactile stimuli while participants are closing their eyes. In this study, we investigated whether the activation in the primary visual cortex induced by tactile stimulation represents tactile stimulus information using neural decoding techniques. Results showed that the primary visual cortex was activated by tactile stimulation even for normal sighted participants but tactile stimulus prediction from the activity in the primary visual cortex was not statistically significant for all participants. These results suggest that the activity in the primary visual cortical evoked by tactile stimulation might not contain tactile stimulus information, at least with regard to types of tactile stimuli used in our experiments., 26330172
01 Apr. 2014 - 31 Mar. 2017 - スパースモデリングによるヒト脳内での物体画像表現ダイナミクスの解明
宮脇陽一
日本学術振興会, 科学研究費助成事業, 電気通信大学, 新学術領域研究(研究領域提案型), Principal investigator, 本年度は、多様な物体画像が「いつ」脳活動に表現されるのかをスパースモデリングを用いて定量化する手法についての研究をさらに押し進めつつ、画像特徴量と物体カテゴリ表現ダイナミクスの関係性の検証を開始した。この目標達成のため、以下の項目を特に重点的に実施した。 １．背景除去済み物体画像を用いたMEG計測実験：MEG信号からの物体カテゴリ予測成績をより高め、結果の信頼性を向上させるため、物体画像刺激に含まれている背景部分を除去した。この背景除去済み物体画像を用いて、新たにMEG信号計測実験を行った。 ２．MEG信号からの皮質上神経電流分布推定と物体カテゴリ情報の時間分解予測解析：背景除去済み画像に対して得られた新しいMEG信号を用いて皮質上神経電流分布を推定した。推定された皮質上神経電流分布の各時刻の信号をパターン識別アルゴリズムを用いて解析することにより、物体カテゴリの情報がいつ脳内に表現されているのかを同定した。 ３．皮質上神経電流分布推定の精度評価：皮質上神経電流分布推定結果の精度評価を行うため、人工データを用いた解析を行った。具体的には、本研究で主たる解析対象とする脳部位に人工的な神経電流源をおき、それをもとに頭皮上で計測される脳磁場信号をシミュレートし、シミュレートした信号から逆に皮質上神経電流分布を推定することで、どの程度正確に原信号を復元出来たかを厳密評価した。 ４．物体カテゴリ画像特徴量の定量化：コンピュータビジョンの分野で物体カテゴリの認識に大きな成果を挙げているDeep convolutional neural network（DCNN）を用いて、MEG信号計測実験で用いた物体画像刺激に対応する高次画像特徴量を抽出した。, 26120514
01 Mar. 2014 - 31 Mar. 2016 - ヒト脳の物体表現様式の解明
KDDI財団, 調査研究助成
2014 - ヒト脳における物体認識メカニズムの時間特性の解明
成茂神経科学研究助成基金, 研究助成
2014 - 神経情報表現に基づく高速物体画像認識アルゴリズムの研究開発
総務省戦略的情報通信研究開発推進制度（ＳＣＯＰＥ）ICTイノベーション創出型研究開発, 研究助成
2014 - ヒト脳神経活動の高時空間分解能解析法の開発と応用
内藤記念科学奨励金, 研究助成
2014 - ヒト脳活動からの画像認識情報の高速抽出技術の研究
矢崎科学技術振興記念財団, 特定研究助成
2014 - 脳情報復号化とデータ・マイニング技術による脳内質感情報表現の抽出
宮脇 陽一
日本学術振興会, 科学研究費助成事業, 新学術領域研究(研究領域提案型), 物体の質感知覚は，私たち人間を含む生物一般の生存に不可欠なプロセスであり，また工業製品の印象や価値に影響を与える重要な要素である．しかし，その脳内表現のメカニズムはこれまでほとんどわかっていない．質感研究の難しさは，質感が非常に高次元の情報であるため，どのような画像手がかりが質感を制御しているのかが捉えにくいことに起因する．また質感知覚は本質的にクロスモーダルな性質をもち，視覚のみならず触覚を含む複数の感覚要素の相互作用の結果もたらされるという複雑性を有する．これらの問題にアプローチするため，本年度は，１）画像の特徴量解析と質感情報との対応関係の定量化，および，２）感覚情報のクロスモーダルな脳内表現の解明，の２つの目標を目指した実験および解析を行った． １）においては，画像の特徴量として近年広く研究されているSIFT特徴量を一般自然画像を用いて計算し，構成された特徴量ベクトルからその画像に共起する形容詞を有意に予測することに成功した．ただし，SIFT特徴量は物体カテゴリのよい記述特徴量となることも知られているため，この両者の要因を切り分けた検討をさらに進める必要がある． ２）においては，今年度は特に，質感知覚において重要な触覚情報の脳内表現の解明に注目した実験および解析を行った．触覚刺激は非磁性ピンアレイ型デバイスで生成した．アーチファクトを極力抑えるため受動触の状態をとり，２点弁別閾の最も小さい手指先端部を刺激箇所とした．触覚刺激は基本的な刺激特徴量（運動方向，エッジの方位など）で定義し，対応する脳活動を機能的磁気共鳴画像装置（fMRI）で計測した．計測された脳活動を多変量解析の手法を用いて解析し，体性感覚野に加え，他の感覚野における脳活動の同定を行った．, 23135534
2011 - 2012 - 感覚知覚世界の可視化技術の研究開発
宮脇陽一
総務省, 戦略的情報通信研究開発推進制度（ＳＣＯＰＥ）若手ＩＣＴ研究者育成型研究開発, Principal investigator
2007 - 2009 - 経頭蓋磁気刺激による神経活動干渉機構の理論的解明
宮脇 陽一
日本学術振興会, 科学研究費助成事業, 若手研究(B), 平成19年度は以下のサブテーマに関して研究を進めた。 1.過渡的な視覚刺激入力条件での抑制効果の解析,およびそのシナプス結合強度に対する影響についての解析 これまでの解析では,簡単化のため,視覚野神経細胞モデルが定常的に発火するような状況を仮定していた。これに加え,本年度は,より実際の状況を忠実に再現するため,刺激入力が過渡的であり,神経細胞の発火パターンも過渡的な場合を解析した。結果,発火パターンが単安定になるシナプス結合強度では,磁気刺激抑制効果を部分的に(早い潜時帯のみ)しか説明できないことが分かった。遅い潜時帯の抑制効果を説明するには,発火パターンが双安定になるシナプス結合強度か,あるいは高次領野からの遅いフィードバック信号が必要になることが分かった。 2.視覚野以外での磁気刺激効果の解析 視覚野を対象として行ってきた一連のモデル解析結果をもとに,他領野での磁気刺激実験結果の再解釈を行った。特に,ワーキングメモリ保持課題時における持続性発火を説明する背側前頭前野の神経回路モデルとの類似性に着目し,ワーキングメモリ機能解析のための新しい実験提案を行った。, 17700415
2005 - 2007 - 大脳皮質磁気刺激による神経活動干渉メカニズムの理論的解明
宮脇 陽一
日本学術振興会, 科学研究費助成事業, 独立行政法人理化学研究所, 若手研究(B), 16700375
2004 - 2004
