Biology subjects

Shinagawa, K.

Publications and source records attributed to Shinagawa, K..

4 recordsLinked to original sources

bioRxiv2024

Brain-Body Interactions Influence the Transition from Mind Wandering to Awareness of Ongoing Thought

Our thoughts are inherently dynamic and often wander far from our current situation (mind wandering, MW). Although previous research revealed that the ascending arousal system shapes neural dynamics to mediate awareness of ongoing thoughts, the physiological states and afferent signals altered by this activation and its effects on awareness are unknown. In this study, we examined electroencephalography (EEG), electrocardiography (ECG), and respiration data before participants were aware of MW during a task in which they focused on external or internal stimuli. We showed that the transition from MW to awareness was characterized by decreased alpha and beta activity and increased heartbeat-evoked potential (HEP) amplitudes. In addition, the participants were more likely to be in the exhalation phase becoming aware, and in the inhalation phase at the time of MW reports. Moreover, changes in cardiac activity and HEP accompanied this pattern when participants were asked to focus on respiration. Based on these findings, we suggest that the release from the increased cognitive load with sustained MW and catching these changes as physiological alterations supporting awareness of MW; moreover, the modulation of the respiratory cycle by focusing on breathing enhances these changes.

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↗

bioRxiv2024

Extending Homeostasis as the Principle of Driving Behavior to the Thought Dynamics Allows Comprehensive Explanation of Mind Wandering

Our thoughts are inherently dynamic, often wandering far from the current situation. Mind-wandering (MW), which is these thought transitions, is crucial for understanding the nature of human thought. Although previous research has identified various factors influencing MW, a comprehensive framework integrating these findings remains absent. Here, we propose that homeostasis has the potential to explain MW and validate the idea through simulations by replicating previous findings. We employed a homeostatic reinforcement learning model where independent drives for the task and others were assigned, and drive reduction became a reward and trained under sustained attention to the response task. We confirmed that the model behaves consistently with the empirical results reported in human experiments, suggesting that the model accurately captures the underlying mechanism of MW. Finally, we discuss the behavioral and neurobiological commonality between human thought and animal behavior and the possibility that the same principle, homeostasis, controls these phenomena.

animal behavior and cognition↗