Satohiro Tajima, PhD

JST RESTO Researcher / Postdoctoral researcher at Lab of Cognitive Computational Neuroscience, University of Geneva.
Bureau C08.1535, CMU, Université de Genève, rue Michel-Servet 1, 1211 Genève, Switzerland.

E-mail: satohiro.tajima [at] gmail.com

Research areas: theoretical neuroscience / dynamical systems.
Topics: decision-making / natural statistics / consciousness.

Recent / Forthcoming:

Articles in preparation / submission:

  • Satohiro TajimaJan Drugowitsch, and Alexandre Pouget. Optimal policy for multi-alternative decisions.

  • Satohiro Tajima. Sensory polymorphism and behavior: when machine vision meets monkey eyes.  preprint

  • Satohiro Tajima, Kowa Koida, Chihiro I. Tajima, Hideyuki Suzuki, Kazuyuki Aihara, and Hidehiko Komatsu. Context-dependent attractor dynamics in visual cortex.  preprint

  • Satohiro Tajima, Takeshi Mita, Douglas J. Bakkum, Hirokazu Takahashi, and Taro Toyoizumi. Locally embedded presages of global network bursts.  preprint


    Journal articles:

    1. Satohiro Tajima, and Ryota Kanai.
      Integrated information and dimensionality in continuous attractor dynamics.
      Neuroscience of Consciousness, 3(1):nix011:1-9, (2017).  pdf

    2. Gouki Okazawa, Satohiro Tajima, and Hidehiko Komatsu.
      Gradual development of visual texture-selective properties 
      between macaque areas V2 and V4.
      Cerebral Cortex, (in press; epub ahead of print, Sep 20, 2016).

    3. Satohiro Tajima*, Jan Drugowitsch*, and Alexandre Pouget.
      Optimal policy for value-based decision-making.
      Nature Communications, 7:12400:1-12, (2016).   pdf

    4. Chihiro I. Tajima*, Satohiro Tajima*, Kowa Koida, Hidehiko Komatsu, Kazuyuki Aihara, and Hideyuki Suzuki.
      Population code dynamics in categorical perception.
      Scientific Reports, 6, 22536:1-13, (2016).   pdf

    5. Satohiro Tajima, Toru Yanagawa, Naotaka Fujii, and Taro Toyoizumi.
      Untangling brain-wide dynamics in consciousness by cross-embedding.
      PLOS Computational Biology, 11(11), e1004537:1-28, (2015).   pdf

    6. Satohiro Tajima, and Kazuteru Komine
      Saliency-based color accessibility.
      IEEE Transactions on Image Processing, 24(3), 1115-1126, (2015).   pdf / slides

    7. Gouki Okazawa, Satohiro Tajima, and Hidehiko Komatsu.
      Image statistics explaining natural texture selectivity in macaque V4.
      PNAS, 112(4), E351-E360, (2015).   pdf

    8. Satohiro Tajima, and Taro Toyoizumi.
      Understanding large-scale complex systems with embedding. (A review in Japanese)
      Seitai no Kagaku (Life Science), 65(5), 478-479, (2014).   pdf

    9. Satohiro Tajima, Ryohei Funatsu, and Yukihiro Nishida.
      Chromatic interpolation based on anisotropy-scale-mixture statistics.
      Signal Processing97, 262-268, (2014).   pdf / matlab code

    10. Satohiro Tajima.
      Defining statistical perceptions with an empirical Bayesian approach.
      Physical Review E, 87(4), 042707:1-10, (2013).   pdf / slides

    11. Hiromasa Takemura, Satohiro Tajima, and Ikuya Murakami.
      Whether dots moving in two directions appear coherent or transparent depends on directional bias induced by surrounding motion.
      Journal of Vision, 11(14):17, 1-17, (2011).    html

    12. Satohiro Tajima, and Masataka Watanabe.
      Acquisition of nonlinear forward optics in generative models: Two-stage “downside-up” learning for occluded vision. 
      Neural Networks, 24(2), 148-158, (2011).   pdf

    13. Satohiro Tajima, Hiromasa Takemura, Ikuya Murakami, and Masato Okada.
      Neuronal population decoding explains the change in signal detection sensitivity caused by task-irrelevant perceptual bias.
      Neural Computation, 22(10), 2586-2614, (2010).   pdf

    14. Satohiro Tajima, and Masato Okada. 
      Discriminating natural image statistics from neuronal population codes. 
      PLOS ONE, 5(3), e9704:1-10, (2010).   pdf

    15. Satohiro Tajima*, Masataka Watanabe*, Chihiro Imai, Kenichi Ueno, Takeshi Asamizuya, Pei Sun, Keiji Tanaka, and Kang Cheng. 
      Opposing effects of contextual surround in human early visual cortex revealed by functional magnetic resonance imaging with continuously modulated visual stimuli. 
      Journal of Neuroscience, 30(9), 3264-3270, (2010).   pdf

      JNS cover

    16. Satohiro Tajima, Masato Inoue, and Masato Okada. 
      Bayesian-optimal image reconstruction for translational-symmetric filters. 
      Journal of the Physical Society of Japan, 77(5), 054803:1-8, (2008).   pdf

    *: equally contributed.


    Patents:

    • Ryota Kanai, and Satohiro Tajima
      Cognitive-state estimation system and cognitive-state estimation method.
      Japan Patent, 2016-82809 (Apr. 18, 2016, applied).

    • Satohiro Tajima
      Color information complementing device, and program.
      Japan Patent, 2013-156743; 2015-027038 (Jul. 29, 2013, applied; Feb. 15, 2015, published).

    • Satohiro Tajima.
      Imaging apparatus and noise elimination program.
      Japan Patent, 2013-96700; 2014-220583 (May 2, 2013, applied; Nov. 22, 2014, published).

    • Satohiro Tajima.
      Inclination angle estimation device, MTF measuring apparatus, inclination angle estimation program and MTF measurement program.
      Japan Patent, 2013-76882; 2014-203162 (Apr. 2, 2013, applied; Oct. 27, 2014, published).

    • Satohiro Tajima.
      Video quality conversion device, conversion parameter generation device, approximated video quality conversion device and program.
      Japan Patent, 2013-37560; 2014-164690 (Feb. 27, 2013 applied; Sep. 4, 2014, published).

    • Satohiro Tajima.
      Video processing apparatus and program.
      Japan Patent, 2012-006258; 2013-145514 (Jan. 16, 2012, applied; Jul. 25, 2013, published).

    Invited talks / Seminars:

    • "Cross-embedding in brain-wide dynamics"
      CMStatistics, London, UK, (Dec. 16-18, 2017).

    • "Optimal policy and neural dynamics for value-based decisions"
      NYU-ECNU Brain and Cognition Institute, Shanghai, China, (Jun. 12, 2017).

    • "Context-dependent neural population attractors in IT cortex"
      Vision Conference, National Institute for Physiological Sciences, Okazaki, Japan, (Jun. 8, 2017).

    • "How should we decide when faced with multiple good options?"
      ATR, Soraku-gun, Japan, (Jun. 2, 2017).

    • "Consciousness and cross-embedding"
      Information Mathematics Seminar (a graduate course lecture), Osaka Unversity, Suita, Japan, (Jun. 1, 2017).

    • "Optimal policy for value-based decision-making"
      Stanford University, Stanford, US, (Mar. 3, 2017).

    • "Consciousness, decision-making, and dimensionality of neural dynamics"
      National Institute for Physiological Sciences, Okazaki, Japan, (Feb. 17, 2017).

    • "Saliency-based color accessibility: opening the 'Umwelt'"
      GIPSA-lab (Grenoble Images Parole Signal Automatique), Grenoble, France, (Dec. 2, 2016).

    • "Context-dependent attractor dynamics in visual cortex"
      Stanford University, Stanford, US, (Nov. 2, 2016).

    • "Optimal policy for value-based decision-making"
      NTT Communication Science Laboratory, Atsugi, Japan, (Oct. 7, 2016).

    • "Optimal policy for value-based decision-making: why are we so slow to decide between two good options?"
      CiNet, Suita, Japan, (Oct. 5, 2016). 

    • "Continuous attractor dynamics may underlie consciousness and will"
      University of Tokyo (Okada lab.), Kashiwa, Japan, (Aug. 10, 2016).

    • "Context-dependent attractor dynamics in sensory cortex"
      University of Tokyo (Aihara lab.), Tokyo, Japan, (Aug. 10, 2016).

    • "Consciousness as embedding: untangling brain-wide dynamics in consciousness by cross-embedding"
      William James Prize lecture, ASSC 20, Buenos Aires, Argentina, (Jun. 14, 2016).

    • "Embedding and empirical measures of consciousness"
      University of Wisconsin-Madison (Tononi Lab.), Madison, US, (Jun. 9, 2016).

    • "Neuro-embedology"
      Consciousness Club, University of Tokyo, Tokyo, Japan, (Feb. 4, 2016).

    • "Neuro-embedology"
      Sackler Centre for Consciousness Science, University of Sussex, Brighton, UK, (Jan. 13, 2016).

    • "Neuro-embedology"
      University of Cambridge (Bekinschtein Lab.), Cambridge, UK, (Jan. 12, 2016).

    • "Untangling brain-wide dynamics in consciousness by cross-embedding"
      UC San Diego (Sugihara Lab.), San Diego, US, (Nov. 4, 2015). 

    • "Untangling brain-wide dynamics in consciousness by cross-embedding"
      University of Wisconsin-Madison (Tononi Lab.), Madison, US, (Oct. 22, 2015).

    • "Untangling complex brain dynamics"
      BLSC Seminar, University of Electro-Communications, Tokyo, Japan, (Jul. 17, 2015).

    • "Untangling complex neurodynamics"
      NTT Communication Science Laboratory, Atsugi, Japan, (Dec. 15, 2014).

    • "Neuroembedology: dynamical relation reflects network structures"
      CiNet, Suita, Japan, (Feb. 6, 2014).

    • "Discriminating natural image statistics from neuronal population codes"
      National Institute for Physiological Sciences, Okazaki, Japan, (Nov. 29, 2010).


    Conference proceedings / abstracts:

    • Satohiro Tajima, Jan Drugowitsch, and Alexandre Pouget.
      Optimal policy for N-alternative value-based decisions.

      Naito Conference, Sapporo, Japan, (Oct. 3-6, 2017). [poster]

    • Satohiro Tajima, and Shizuo Kaji.
      Topology of brain-wide dynamics in consciousness.

      ASSC 21, Beijing, China, (Jun. 13-17, 2017). [poster]

    • Satohiro Tajima.
      Embedding in brain-wide dynamics.
      RIMS Meeting: Dynamical Systems - Investigation for Collaborations between Theory and Applications, Kyoto, Japan, (Jun. 5-6, 2017). [talk]

    • Satohiro Tajima, Jan Drugowitsch, and Alexandre Pouget.
      Optimal policy leads to “irrational” choice behavior under multiple alternatives.
      Cosyne 17, Salt Lake City, US, (Feb. 25, 2017). [poster]

    • Satohiro Tajima, Kowa Koida, Chihiro I. Tajima, Hideyuki Suzuki, Kazuyuki Aihara, and Hidehiko Komatsu.
      Task demand modulates collective attractor dynamics in visual cortex.
      Cosyne 17, Salt Lake City, US, (Feb. 25, 2017). [poster]

    • Satohiro TajimaJan Drugowitsch, and Alexandre Pouget.
      Optimal policy for multi-alternative decision-making.
      SfN2016, San Diego, US, (Nov. 14, 2016). [talk]

    • Satohiro Tajima, Joshua Balsters, and Ryota Kanai.
      Local EEG dynamics embed global fMRI states.
      OHBM2016, Genève, Switzerland, (Jun. 28, 2016). [poster]

    • Satohiro Tajima, and Jacobo Diego Sitt.
      Cross-embedding complexity: a dynamical-systems account of consciousness in noncommunicative patients.
      ASSC 20, Buenos Aires, Argentina, (Jun. 18, 2016). [talk]

    • Satohiro Tajima, and Ryota Kanai.
      Integrated information in continuous attractor embedding
      .
      ASSC 20, Buenos Aires, Argentina, (Jun. 15, 2016). [poster]

    • Satohiro Tajima.
      Dynamical dualism paradox.
      ASSC 20, Buenos Aires, Argentina, (Jun. 15, 2016). [poster]

    • Satohiro Tajima, Daniel Robles Llana, Jan Drugowitsch, and Alexandre Pouget.
      Normalization and urgency cooperate in optimal multi-alternative decisions.
      Cosyne 16, Salt Lake City, US, (Feb. 27, 2016). [talk]

    • Satohiro Tajima, Jan Drugowitsch, and Alexandre Pouget.
      Why are we so slow to decide between two good options?
      Cosyne 16, Salt Lake City, US, (Feb. 27, 2016). [poster]

    • Jan Drugowitsch, Satohiro Tajima, and Alexandre Pouget.
      Why do we take so long when faced with two good options?
      SfN 45th annual meeting, Chicago, US (Oct. 17, 2015). [poster]

    • Satohiro Tajima, and Masanori Shimono.
      Global delayed propagation of electrical signals in primate cortex.
      SfN 45th annual meeting, Chicago, US (Oct. 20, 2015). [poster]

    • Gouki Okazawa, Satohiro Tajima, and Hidehiko Komatsu.
      Comparison of natural texture selectivity and underlying image-statistics representation between macaque V2 and V4.
      Neuroscience 2015, Kobe, Japan, (Jul. 28, 2015). [poster]

    • Satohiro Tajima, Toru Yanagawa, Naotaka Fujii, and Taro Toyoizumi.
      Hierarchy of complexity embedded in awake brain dynamics.
      ASSC 19, Paris, France (Jul. 9, 2015). [poster]

    • Satohiro Tajima, and Taro Toyoizumi.
      Characterizing complexity of intracortical interaction.
      SfN 44th annual meeting, Washington DC, US (Nov. 19, 2014). [talk]

    • Gouki Okazawa, Satohiro Tajima, and Hidehiko Komatsu.
      Image statistics explaining natural texture selectivity in macaque V4.
      Neuroscience 2014, Yokohama, Japan, (Sep. 11, 2014). [poster]

    • Satohiro Tajima, Kowa Koida, Chihiro I. Tajima, Kazuyuki Aihara, Hideyuki Suzuki, and Hidehiko Komatsu.
      Task-dependent neural population dynamics in sensory cortex.
      VSS 2014 annual meeting, St. Pete Beach, US, (May 18, 2014). [talk]

    • Satohiro Tajima, and Taro Toyoizumi.
      Neuroembedology: dynamical relation reflects network structures.
      Cosyne 14, Salt Lake City, US, (Feb. 27, 2014). [poster]

    • Gouki Okazawa, Satohiro Tajima, and Hidehiko Komatsu.
      Natural texture selectivity of macaque V4 neurons examined by adaptive sampling.
      SfN 43th annual meeting, San Diego, US, (Nov. 12, 2013). [poster]

    • Satohiro Tajima, Kowa Koida, Chihiro I. Tajima, Kazuyuki Aihara, Hideyuki Suzuki, and Hidehiko Komatsu.
      Categorical modulation in population coding of color.
      Neuro 2013, Kyoto, Japan, (Jun. 21, 2013). [talk]

    • Gouki Okazawa, Satohiro Tajima, and Hidehiko Komatsu.
      Image features determining texture selectivity of macaque V4 neurons revealed by adaptive sampling.
      Neuro 2013, Kyoto, Japan, (Jun. 21, 2013). [talk]

    • Satohiro Tajima, and Kazuteru Komine.
      Saliency-based color accessibility: Theory into practice.
      IDW/AD, Kyoto, Japan, (Dec. 7, 2012). [talk] pdf / slides

    • Hiromasa Takemura, Satohiro Tajima, and Ikuya Murakami.
      Motion integration and segregation modulated by surrounding motion.
      VSS 2011 annual meeting, Naples, US, (May 6-11, 2011). [talk]

    • Chihiro Imai, Satohiro Tajima, Kazuyuki Aihara, and Hideyuki Suzuki.
      Hybrid coding of colors: how can we unify color discrimination, categorization and memory?
      VSS 2011 annual meeting, Naples, US, (May 6-11, 2011). [poster]

    • Chihiro Imai, Satohiro Tajima, Kazuyuki Aihara, and Hideyuki Suzuki.
      Higher order processing and memory of color.
      The 1st International Symposium on Innovative Mathematical Modeling, Tokyo, Japan, (Mar. 1, 2011). [poster]

    • Hiromasa Takemura, Satohiro Tajima, and Ikuya Murakami.
      Modulation of motion integration and segregation by surrounding motion: psychophysics and model.
      Cosyne 11, Salt Lake City, US, (Feb. 26, 2011). [poster]

    • Chihiro Imai, Satohiro Tajima, Kazuyuki Aihara, and Hideyuki Suzuki.
      Hybrid population code: bridging discrimination, categorization, and memory.
      Cosyne 11, Salt Lake City, US, (Feb. 25, 2011). [poster]

    • Chihiro Imai, Satohiro Tajima, Kazuyuki Aihara, and Hideyuki Suzuki.
      A neural network model for categorical effects in color memory.
      Artificial Life and Robotics 16th, Beppu, Japan, (Jan. 21, 2011). [talk]

    • Hiromasa Takemura, Satohiro Tajima, and Ikuya Murakami.
      Contextual modulation of visual motion integration and segregation: psychophysics and model.
      The National Institute for Physiological Sciences, 41st International Symposium "New Frontiers in Brain Science", Okazaki, Japan, (Dec., 16-18 2010). [poster] 

    • Satohiro Tajima, and Masato Okada.
      Population coding of natural image statistics.
      Neuro 2010, Kobe, Japan, (Sep. 2, 2010). [poster]

    • Satohiro Tajima, Hiromasa Takemura, Ikuya Murakami, and Masato Okada.
      Motion detection sensitivity modulated by a task-irrelevant illusory motion in an orthogonal direction: a population decoding model.
      SfN 39th annual meeting, Chicago, US, (Oct. 19, 2009). [poster]

    • Satohiro Tajima, Hiromasa Takemura, Ikuya Murakami, and Masato Okada.
      Neuronal population decoding explains the change in motion detection sensitivity caused by task-irrelevant motion induction.
      The National Institute for Physiological Sciences, International Workshop for Scientific Study of Consciousness, Okazaki, Japan, (Sep. 19, 2009). [poster]

    • Satohiro Tajima, Masataka Watanabe, Chihiro Imai, Kenichi Ueno, Takeshi Asamizuya, Keiji Tanaka, and Kang Cheng.
      Opposing effects of contextual surround in human early visual cortex revealed by fMRI with continuously modulated visual stimuli.
      SfN 38th annual meeting, Washington DC, US, (Nov. 18, 2008). [poster]