Biology subjects

Sakuragi, M.

Publications and source records attributed to Sakuragi, M..

3 recordsLinked to original sources

bioRxiv2025

How the Heart Shapes the Mind: The Role of Cardiac Interoception in the Interaction between Autonomic Nervous Activity and Self-related Thoughts

Our thoughts often drift away from the tasks at hand. Various factors influence this phenomenon, including changes in the external environment, individual cognitive characteristics, and fluctuations in bodily responses. This study investigated the relationship between autonomic nervous fluctuations and thought state transitions, focusing on individual differences such as cardiac interoception. First, the heartbeat counting task was conducted, and the difference between the reported and actual number of heartbeats was used as an index of interoceptive accuracy. The participants then completed an auditory attention task while their cardiac activities were monitored. During the task, thought probes were randomly presented, and participants selected their thought content from eight categories and rated aspects such as task concentration and arousal. We estimated trial-by-trial thought states in a data-driven manner and examined how the current thought state, autonomic nervous activity, and individual cardiac interoceptive accuracy influenced the thought state in the next trial. The results demonstrated a strong association between higher cardiac interoceptive accuracy and the maintenance of similar states in subsequent trials when accelerated heart rates occurred during self-related thought states. Furthermore, the participants with higher depressive tendencies and interoceptive accuracy exhibited an increased likelihood of transitioning to self-related states when experiencing decreased heart rate during task-concentrated states. These results suggest that accurately detecting heart rate changes associated with specific thought states facilitates updates in first-person conscious experience, thereby biasing the transition patterns of subsequent thought states. This study provides new insights into the cognitive and physiological mechanisms underlying the dynamics of spontaneous thought.

neuroscience↗

bioRxiv2024

The Body Mirroring Thought: The Relationship Between Thought Transitions and Fluctuations in Autonomic Nervous Activity Mediated by Interoception

Our thought states change unconsciously. This study verified that the transference of thought states varies with fluctuations in autonomic nervous activity, and that this effect is modulated by interoceptive accuracy. The participants completed the heartbeat counting task (HCT) and vigilance task (VT). We assessed the participants interoceptive accuracy based on their performance on the HCT. The VT is a simple attention task, and during this task, we asked the participants to report the content and contemplation of their thoughts. Consequently, participants with accurate interoception were more likely to remain in a highly contemplative thought state when sympathetic activity was activated. In contrast, the dominance of parasympathetic activity facilitated transitions to different thought states or experiences of less contemplative thought states in them. The results suggest that even subtle changes in bodily responses at rest can affect thought transitions in people with accurate interoception.

neuroscience↗

bioRxiv2024

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

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.

neuroscience↗