Publications by authors named "Yokosawa K"

Communication, especially conversation, is essential for human social life. Many previous studies have examined the neuroscientific underpinnings of conversation, i.e.

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Cross-modal correspondences refer to associations between stimulus features across sensory modalities. Previous studies have shown that cross-modal correspondences modulate reaction times for detecting and identifying stimuli in one modality when uninformative stimuli from another modality are present. However, it is unclear whether such modulation reflects changes in modality-specific perceptual processing.

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Previous studies have reported that, in working memory, the processing of visuospatial information and phonological information have different neural bases. However, in these studies, memory items were presented via different modalities. Therefore, the modality in which the memory items were presented and the strategy for memorizing them were not rigorously distinguished.

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Visual object recognition is facilitated by contextually consistent scenes in which the object is embedded. Scene gist representations extracted from the scenery backgrounds yield this scene consistency effect. Here we examined whether the scene consistency effect is specific to the visual domain or if it is crossmodal.

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Humans subjectively experience a scene as rendered in color across the entire visual field, a visual phenomenon called "pan-field color" (Balas & Sinha, 2007). This experience is inconsistent with the limited color sensitivity in the peripheral visual field. We investigated the effects of visual attention allocated to the peripheral visual field on the pan-field color illusion.

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Cross-modal correspondences refer to associations between feature dimensions of stimuli across sensory modalities. Research has indicated that correspondence between audiovisual stimuli influences whether these stimuli are integrated or segregated. On the other hand, the audiovisual integration process plastically changes to compensate for continuously observed spatiotemporal conflicts between sensory modalities.

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Auditory communication is an essential form of human social interaction. However, the intra-brain cortical-oscillatory drivers of auditory communication exchange remain relatively unexplored. We used improvisational music performance to simulate and capture the creativity and turn-taking dynamics of natural auditory communication.

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Communication is one of the most important abilities in human society, which makes clarification of brain functions that underlie communication of great importance to cognitive neuroscience. To investigate the rapidly changing cortical-level brain activity underlying communication, a hyperscanning system with both high temporal and spatial resolution is extremely desirable. The modality of magnetoencephalography (MEG) would be ideal, but MEG hyperscanning systems suitable for communication studies remain rare.

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Liquid-liquid phase separation (LLPS) is an important phenomenon in biology, and it is desirable to develop quantitative methods to analyze protein droplets generated by LLPS. This study quantified the change in protein concentration in a droplet in label-free and single-droplet conditions using Raman imaging and the Raman band of water as an intensity standard. Small changes in the protein concentration with variations in pH and salt concentration were observed, and it was shown that the concentration in the droplet decreases as the conditions become less favorable for droplet formation.

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Electrophysiological studies have demonstrated that theta-band activity is useful for investigating neural mechanisms of memory. However, mechanisms specifically driving memory performance remain poorly understood. In sequential memory, performance can be artificially attenuated by shortening the inter-stimulus interval (ISI) between memory item presentations.

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Temporal ventriloquism refers to the shift in the perceived timing of a visual stimulus towards a transient auditory stimulus presented close in time. This effect is demonstrated by greater sensitivity of temporal order judgments of two visual stimuli when a sound is presented before the first visual stimulus and after the second visual stimulus. Recent studies suggest that temporal ventriloquism is affected by cross-modal correspondence between auditory pitch and visual elevation but not by correspondence between pitch and visual size.

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The space surrounding the body in which individuals interact with the environment is known as the peripersonal space (PPS). Previous studies have reported that PPS has multisensory nature. However, the relationship between the multisensory nature of PPS and an individuals' defensive actions has not been fully clarified to date.

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People react faster to visuo-tactile stimuli presented near the body (i.e., in peripersonal space) than to tactile stimuli presented alone.

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The space surrounding our body is called peripersonal space (PPS). It has been reported that visuo-tactile facilitation occurs more strongly within PPS than outside PPS. Furthermore, previous research has revealed several methods by which PPS can be extended.

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Humans can perceive a coherent visual scene despite a low spatial resolution in peripheral vision. How does the visual system determine whether an object exists in the periphery? We addressed this question by focusing on the extinction illusion in which a disk becomes subjectively invisible when presented at the intersection of grids. We hypothesized that the disk would go unnoticed when the stimuli with and without the disk produced the same strength of visual signals.

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Grapheme-color synesthesia is a condition in which the visual perception of letters or numbers induces a specific color sensation. The consistency of grapheme-color association has been considered as a fundamental characteristic of synesthesia. However, recent studies have indicated that this association can change across the adult lifespan, and it has become necessary to investigate the factors behind the changes within each synesthete.

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Grapheme-colour synaesthesia is a condition in which the visual perception of letters or numbers induces a specific colour sensation. In this study, we demonstrated that the apparent physical brightness of graphemes is modulated by the synaesthetic colours elicited by them. Synaesthetes first selected a synaesthetic colour corresponding to each capital letter and digit.

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Several studies have shown that space immediately surrounding the body, or the peripersonal space is represented differently in the brain from the more distant extra-personal space. Moreover, the boundary of peripersonal space can be extended to space surrounding the tip of a tool held by the hand. However, it is not known if tools need to be connected to the body to modulate the peripersonal space.

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Face to face communication is interactive, and involves continuous feedforward and feedback of information, thoughts, and feelings to the opposite party. To accurately assess the neural processing underlying these interactions, synchronous and simultaneous recording of the brain activity from both parties is needed, a method known as hyperscanning. Here, we investigated the neural processing underlying nonverbal face-to-face communication using a magnetoencephalographic (MEG) hyperscanning system, comprising two fiber optically connected MEGs.

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Mild Cognitive Impairment (MCI) is a border or precursor state of dementia. To optimize implemented interventions for MCI, it is essential to clarify the underlying neural mechanisms. However, knowledge regarding the brain regions responsible for MCI is still limited.

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Previous research suggests that the size of one's body is used as a metric to scale the external world. On the other hand, the influence of information from the external world on the perception of body size is unclear. It has been suggested that increased inter-pupillary distance (IPD) leads people to perceive the external world as smaller than it actually is.

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Synesthesia is a condition in which the perception of a stimulus in one modality automatically triggers a secondary sensation in another modality or processing stream. Our study focused on grapheme-color synesthesia, in which the visual perception of letters or numbers (graphemes) induces a specific color sensation (the synesthetic color). Grapheme-color synesthetes do not typically experience colors for novel graphemes.

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Facile fabrication and high ambient stability are strongly desired for the practical application of temperautre sensor in real-time wearable healthcare. Herein, a fully printed flexible temperature sensor based on cross-linked poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was developed. By introducing the crosslinker of (3-glycidyloxypropyl)trimethoxysilane (GOPS) and the fluorinated polymer passivation (CYTOP), significant enhancements in humidity stability and temperature sensitivity of PEDOT:PSS based film were achieved.

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Numerous studies have demonstrated that brain rhythms are modulated according to memory performance or memory processing. In sequential memory tasks, memory performance can be reduced by shortening the intervals between memory item presentations. To clarify the neurophysiological mechanism underlying this, we recorded magnetoencephalograms in 33 healthy volunteers performing two sequential memory tasks with either short or long intervals between memory items (hereafter, fast and slow conditions, respectively).

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