Biology subjects

Kuwamizu, R.

Publications and source records attributed to Kuwamizu, R..

6 recordsLinked to original sources

bioRxiv2026

Right-lateralized prefrontal signature with successful Stroop-like interference control in early childhood

The Stroop effect is a canonical measure of executive control, yet its neural architecture has been defined largely in literate children and adults, where left frontal mechanisms have long been implicated in resolving verbal conflict. How the developing brain supports Stroop-like interference control before literacy and stable verbal responding are established remains unknown. Here we show that successful interference control in early childhood is associated with the selective engagement of right lateral prefrontal regions. We used multichannel functional near-infrared spectroscopy to measure prefrontal hemodynamics in 94 children aged 35-79 months during a color-pointing Stroop-like task, in which children pointed to colors in response to spoken color names. Stroop-like conflict elicited broad activation across bilateral lateral prefrontal regions, a conflict response already present from around 3 years of age and did not show a detectable age-related increase. By contrast, individual differences in accuracy under conflict were selectively associated with greater activation in the right dorsolateral and right rostrolateral prefrontal cortices, independent of age. These findings suggest that right lateral prefrontal regions play an important role in successful interference control in early childhood, indicating that preschool Stroop-like control is not merely a weaker form of the adult left-lateralized system.

neuroscience↗

bioRxiv2026

Acute running improves mood via changes in interoceptive sensibility

PurposeInteroception is the sensing and interpretation of internal bodily signals and may be a key process linking exercise-induced bodily changes to mood. This study examined whether acute moderate-intensity treadmill running changes interoception and mood states and whether running-related changes in interoception statistically account for mood improvement. MethodsTwenty-seven healthy young adults completed a within-subject crossover experiment consisting of 15 min of moderate-intensity treadmill running at 50% estimated [V]O2peak and seated rest on separate days. Before and after each condition, cardiac interoceptive accuracy was assessed using heartbeat counting and heartbeat tapping tasks, present-moment interoceptive sensibility using a state-adapted Body Perception Questionnaire (BPQ), and mood using the Profile of Mood States. Running-related changes were calculated as {Delta}RUN - {Delta}CTL. ResultsCompared with seated rest, running reduced total mood disturbance (TMD) and tension-anxiety (TA) and increased vigor-activity (VA). Running did not significantly change task-based indices of cardiac interoceptive accuracy but increased BPQ scores. Greater running-related increases in BPQ scores were associated with greater reductions in TMD (r = -.61, p < .001), TA (r = -.45, p = .018), and depression-dejection (r = -.49, p = .009). Greater increases in heartbeat tapping task d' were associated with greater increases in VA (r = .56, p = .003). Mediation analysis indicated that BPQ changes were statistically consistent with an indirect pathway linking running to reduced TMD, with weaker exploratory evidence for TA. ConclusionsA single bout of moderate-intensity running improved mood and increased present-moment interoceptive sensibility, but not task-based cardiac interoceptive accuracy. Enhanced subjective awareness of bodily sensations may be one proximal process related to the mood benefits of acute running.

neuroscience↗

bioRxiv2026

Dissociable pupil-linked arousal during overt and inner speech

Inner (covert) speech, the silent production of language in ones mind, plays a central role in human cognition and is known to activate speech-related cortical regions while also requiring executive and attentional resources. However, the conventional focus on cortical similarity or dissimilarity between inner and overt speech leaves unaddressed the question of whether arousal systems sustain cortical language processing. Here, using pupillometry across three controlled counting experiments, we show a dissociation between inner and overt speech. Overt speech consistently led to pupil dilation across all conditions. Inner speech, by contrast, produced a strikingly different profile: pupil constriction during simple counting, no deviation from baseline during noun-phrase counting, and clear dilation only under a high cognitive load, but with dilation remaining significantly less than that for overt speech in every condition. Covert verbal production thus proceeds at a reduced arousal cost, yet this cost scales flexibly with task demands rather than being fixed. This pupillometric dissociation reveals that inner and overt speech occupy fundamentally distinct arousal states, even when their cortical substrates partially overlap. These findings open a non-invasive window for tracking inner speech physiology across development, individual differences, and clinical populations in whom inner speech is altered.

neuroscience↗

bioRxiv2026

Emergent blink rate in early childhood is associated with neural origins of executive function

Executive function develops rapidly in early childhood and predicts later success in life, yet its neurobiological correlates during this period remain poorly understood. In adults, executive function is supported by prefrontal-striatal circuits under neuromodulatory control, including dopamine. Here, we show that spontaneous eye-blink rate (sEBR), a physiological output influenced by neuromodulatory systems, is associated with the developmental trajectory of executive function and prefrontal functional differentiation. We used fNIRS to monitor prefrontal cortex (PFC) activation in 113 children (35-80 months) during a cognitive flexibility task. With increasing age, the childrens task performance improved, and their PFC activation showed greater right-hemisphere and dorsal bias, reflecting functional differentiation. Importantly, higher sEBR was also associated with this right-dorsal PFC activation and with better task performance. The current findings demonstrate that emergent sEBR is associated with the neural origins of executive function development in young children. This highlights the potential of sEBR to serve as a unique and previously unrecognised indicator of this critical developmental neural mechanism.

neuroscience↗

bioRxiv2024

Exercising with virtual reality is potentially better for the working memory and positive mood than cycling alone

Although virtual reality (VR) exercise has attracted attention as a factor in exercise habituation due to its mood-enhancing effects, its impact on brain function remains unclear. This study, involving 23 healthy university students, used functional magnetic resonance imaging (fMRI) to explore how VR exercise affects working memory, a key executive function, and its underlying neural mechanisms. Our findings indicate that a 10-min VR exercise session improved mood (arousal and vitality level) and working memory task performance (3-back task) more effectively than exercise or rest alone. Furthermore, the results confirmed that increased vitality from exercise and VR exercise interventions was associated with improved 3-back task performance. However, specific brain regions contributing to this enhancement remain unidentified. These results highlight VR exercise as the optimal exercise program for enhancing working memory function by increasing vitality level. These insights underscore VRs potential as a novel exercise modality with benefits extending beyond exercise adherence to potentially preventing dementia and depression.

neuroscience↗

bioRxiv2024

Slow running benefits: Boosts in mood and facilitation of prefrontal cognition even at very light intensity

Although running upright has been reported to have positive effects on both physical and mental health, the minimum running intensity/speed that would benefit mood and prefrontal cognition is not yet clear. For this reason, we aimed to investigate the acute effect of very slow running, which is classified as a very light intensity exercise, on mood, executive function (EF), and their neural substrates in the prefrontal cortex (PFC). Twenty-four healthy participants completed a 10-minute very slow running session on a treadmill at 35% [Formula] and a resting control session in randomized order. EF was measured using the Stroop task and the mood state was measured using the Two-Dimensional Mood Scale (TDMS) before and after both sessions. Cortical hemodynamic changes while performing the task were monitored using functional near-infrared spectroscopy (fNIRS). The results show that ten minutes of very slow running significantly enhanced mood, reduced Stroop interference time (i.e., enhanced EF), and elicited left lateral PFC activation. Moreover, head acceleration, the magnitude of up-and-down oscillations, was measured during running, and a significant positive correlation with pleasant mood was found. Head acceleration is a remarkable characteristic of running and may be one of the factors related to a pleasant mood induced by very slow running. In conclusion, the current study reveals that a single bout of running, even at very slow speed, elicits a pleasant mood and improved executive function with enhancing activation in prefrontal subregions. This shed light on the slow running benefits to brain health.

neuroscience↗