研究者詳細 - 森本　智志

森本　智志（モリモト　サトシ）

Morimoto, Satoshi

写真a

所属（所属キャンパス）: 研究所・センター等グローバルリサーチインスティテュート（三田）

職名: 特任助教（有期）

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Two-in-one system and behavior-specific brain synchrony during goal-free cooperative creation: an analytical approach combining automated behavioral classification and the event-related generalized linear model

Mingdi Xu, Satoshi Morimoto, Eiichi Hoshino, Kenji Suzuki, Yasuyo Minagawa

Neurophotonics 10 （ 1 ） 013511 2023年02月

筆頭著者, 査読有り

　概要を見る

*Mingdi Xu and Satoshi Morimoto equally contributed to this work.

Our proposed analytical approach combining computer vision and WTC-GLM can be applied to extract inter-brain synchrony associated with social behaviors of interest.
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Effects of Hemodynamic Differences on the Assessment of Inter-Brain Synchrony Between Adults and Infants

Morimoto S., Minagawa Y.

Frontiers in Psychology （Frontiers in Psychology） 13 873796 2022年06月

査読有り

　概要を見る

The simultaneous recording of brain activity in two or more people, termed hyperscanning, is an emerging field of research investigating the neural basis of social interaction. Hyperscanning studies of adult–infant dyads (e.g., parent and infant) have great potential to provide insights into how social functions develop. In particular, taking advantage of functional near-infrared spectroscopy (fNIRS) for its spatial resolution and invulnerability to motion artifacts, adult–infant fNIRS may play a major role in this field. However, there remains a problem in analyzing hyperscanning data between adult and young populations. Namely, there are intrinsic differences in hemodynamic time latencies depending on age, and the peak latency of the hemodynamic response function (HRF) is longer in younger populations. Despite this fact, the effects of such differences on quantified synchrony have not yet been examined. Consequently, the present study investigated the influence of intrinsic hemodynamic differences on wavelet coherence for assessing brain synchrony, and further examined the statistical removal of these effects through simulation experiments. First, we assumed a social signal model, where one counterpart of the dyad (e.g., infant) sends a social signal to the other (e.g., parent), which eventually results in simultaneous brain activation. Based on this model, simulated fNIRS activation sequences were synthesized by convolving boxcar event sequences with HRFs. We set two conditions for the event: synchronized and asynchronized event conditions. We also modeled the HRFs of adults and infants by referring to previous studies. After preprocessing with additional statistical processing, we calculated the wavelet coherence for each synthesized fNIRS activation sequence pair. The simulation results showed that the wavelet coherence in the synchronized event condition was attenuated for the combination of different HRFs. We also confirmed that prewhitening via an autoregressive filter could recover the attenuation of wavelet coherence in the 0.03–0.1 Hz frequency band, which was regarded as being associated with synchronous neural activity. Our results showed that variability in hemodynamics affected the analysis of inter-brain synchrony, and that the application of prewhitening is critical for such evaluations between adult and young populations.
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Toward Interactive Social Neuroscience: Neuroimaging Real-World Interactions in Various Populations

Minagawa Y., Xu M., Morimoto S.

Japanese Psychological Research （Japanese Psychological Research） 60 （ 4 ） 196 - 224 2018年10月

査読有り, ISSN 00215368

　概要を見る

Human social activity is a continuous dynamic behavior consisting of live social signal exchanges; thus, studying interactions among multiple humans is critical to understanding social cognition. Indeed, social neuroscience focusing on such aspects—interactive social neuroscience—is an emerging field of interest. Functional near-infrared spectroscopy (fNIRS) has played a significant role in accelerating this field by enabling real-world neuroimaging for various populations. The present paper will first review previous hyperscanning studies using functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and electroencephalography (EEG). We will then summarize attempts and findings of fNIRS hyperscanning studies on social interaction in adult populations. Finally, we will review recent investigations of interactive social neuroscience in young populations and show preliminary results from a mother–infant hyperscanning study. These studies have predominantly revealed synchronized brain activities between humans and have identified conditions in which such inter-personal connectivity was found to be increased. Furthermore, these studies suggest possible mechanisms of inter-brain coupling: a process that recruits both mirror system and mentalization networks. Although fNIRS hyperscanning of infants remains limited, the reviewed literature demonstrates significant potential for fNIRS to disclose the interactive social brain and its development.
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Computational-Model-Based Analysis of Context Effects on Harmonic Expectancy

Satoshi Morimoto, Gerard B. Remijn, Yoshitaka Nakajima

PLOS ONE （PUBLIC LIBRARY SCIENCE） 11 （ 3 ） e0151374 2016年03月

筆頭著者, 査読有り, ISSN 1932-6203

　概要を見る

Expectancy for an upcoming musical chord, harmonic expectancy, is supposedly based on automatic activation of tonal knowledge. Since previous studies implicitly relied on interpretations based on Western music theory, the underlying computational processes involved in harmonic expectancy and how it relates to tonality need further clarification. In particular, short chord sequences which cannot lead to unique keys are difficult to interpret in music theory. In this study, we examined effects of preceding chords on harmonic expectancy from a computational perspective, using stochastic modeling. We conducted a behavioral experiment, in which participants listened to short chord sequences and evaluated the subjective relatedness of the last chord to the preceding ones. Based on these judgments, we built stochastic models of the computational process underlying harmonic expectancy. Following this, we compared the explanatory power of the models. Our results imply that, even when listening to short chord sequences, internally constructed and updated tonal assumptions determine the expectancy of the upcoming chord.
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An introduction to the measurement of auditory event-related potentials (ERPs)

Gerard B. Remijn, Emi Hasuo, Haruna Fujihira, Satoshi Morimoto

Acoustical Science and Technology （Acoustical Society of Japan） 35 （ 5 ） 229 - 242 2014年

ISSN 1347-5177

　概要を見る

In 1939, Pauline Davis reported the first study on event-related potentials (ERPs) performed on awake humans. ERPs are time-locked brain potentials that occur in response to cognitive, motor or perceptual events. The events used by Davis were sounds, and in the decades that followed her landmark study ERP research significantly contributed to the knowledge of auditory perception and neurophysiology we have today. ERPs are very well suited to study neural responses to sound stimuli, since the researcher can monitor the brain's registration of sound edges and spectral changes in sound on a millisecond-by-millisecond basis. In this overview we will introduce basic concepts of auditory ERP research. The overview includes descriptions of typical ERP components, experimental paradigms, sound stimuli, research methodology, and ways to analyze data.
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