KEIO RESEARCHERS INFORMATION SYSTEM

Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Effects of unconscious tactile stimuli on autonomic nervous activity and afferent signal processing

  Sakuragi M., Tanaka Y., Shinagawa K., Tsuji K., Umeda S.

  International Journal of Psychophysiology 205 2024.11

  ISSN  01678760

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  Autonomic nervous system (ANS) is a mechanism that regulates our internal environment. In recent years, the interest in how tactile stimuli presented directly to the body affect ANS function and cortical processing in humans has been renewed. However, it is not yet clear how subtle tactile stimuli below the level of consciousness affect human heart rate and cortical processing. To examine this, subthreshold electrical stimuli were presented to the left forearm of 43 participants during an image-viewing task, and electrocardiogram (ECG) and electroencephalogram (EEG) data were collected. The changes in the R-wave interval of the ECG immediately after the subthreshold electrical presentation and heartbeat-evoked potential (HEP), the afferent signal processing of cardiac activity, were measured. The results showed that heart rate decelerated immediately after the presentation of subthreshold electrical stimuli. The HEP during stimulus presentation was amplified for participants with greater heart rate acceleration immediately after this deceleration. The magnitude of these effects depended on the type of the subthreshold tactile stimuli. The results suggest that even with subthreshold stimulation, the changes in autonomic activity associated with orienting response and related afferent signal processing differ depending on the clarity of the tactile stimuli.

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• Temporal changes in attentional resources consumed by mind-wandering that precede awareness: An ERP study

  Shinagawa K., Ito Y., Tsuji K., Tanaka Y., Odaka M., Shibata M., Terasawa Y., Umeda S.

  Neuroimage: Reports 1 ( 4 )  2021.12

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  A relationship between the awareness of mind-wandering (MW) and the disruption of MW because of external stimuli has previously been reported. Attention often fluctuates without external stimuli and such disruptions can spontaneously precede awareness of MW. To elucidate whether changes in attentional resources used by MW exist, we used event-related potentials (ERPs), focusing on the P300 (P3) ERP component as an index of attention to a task. Participants performed a simple task, in which they pressed a key in synchrony with continually presented tones. Moreover, they were asked to stop the response whenever they became aware of their MW. We analyzed the P3 induced by the tones before self-reports of MW using a state–space model that was used for analysis to detect changes over time. The results revealed that the mean amplitude of P3 increased significantly from the third to the second tone before the self-reports; no other clear increasing or decreasing tendencies were observed. We concluded that the attentional resources allocated to the main task returned, suggesting that such awareness requires a decrease in resources to task-unrelated thoughts. These findings highlight a transitional state related to awareness between the MW state and self-reports. Therefore, the state immediately before self-reports should not be defined as merely an MW state when using the self-caught method.

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• Products With High Purchase Frequency Require Greater Inhibitory Control: An Event-Related Potential Study

  Tsuji K., Shibata M., Terasawa Y., Umeda S.

  Frontiers in Psychology 12 2021.09

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  One’s past behavior influences their present behavior. The effects of such response history have often been tested using response inhibition tasks. Since previous studies have highlighted the effect of immediate action history formed directly before the subsequent response in a laboratory environment, we aimed to elucidate the longer-term effects of response history, using repetitive and habitual consumer behavior in daily life as the response history. We used event-related potentials recorded in a Go/No-go task to investigate brain activity related to inhibitory control, hypothesizing that stimuli with a high frequency of choice in everyday life would elicit stronger inhibition-related activity, that is, the No-go-N2 component. Participants were asked to evaluate the frequency of purchase and use of some products, such as food and drink or social networking services (SNS) in everyday situations. Images of each product were assigned as stimuli in the Go and No-go trials according to the frequency of choice. The results showed that frequently purchased No-go stimuli yielded a larger amplitude of the No-go-N2 component and a negative shift between 200 and 300ms after the presentation of No-go stimuli. The results suggest that frequently chosen products evoke stronger inhibition conflicts and require greater cognitive control to withhold a response. Our findings showed that repeated purchase behavior in daily life forms a response history and has a long-term influence on the inhibition of even simple approaching behaviors, such as button pressing.

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Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• PSYCHOLOGY 2

  2025

• PSYCHOLOGY 1

  2025

• PSYCHOLOGY 2

  2024

• PSYCHOLOGY 1

  2024