Biology subjects

Sugino, H.

Publications and source records attributed to Sugino, H..

6 recordsLinked to original sources

bioRxiv2026

Loud acoustic stimulation reveals an online reticulospinal contribution to long-latency reflexes in humans

The long-latency reflex (LLR), the fastest feedback response that recruits supraspinal pathways, is an important model for understanding how descending motor pathways shape rapid corrective responses in humans. While the corticospinal tracts contribution to the LLR has been well established, that of the reticulospinal tract, the other major descending motor pathway, remains purely speculative. To address this online contribution to the generation of the LLR, we used loud acoustic stimulation (LAS), which can strongly engage brainstem circuits including the pontomedullary reticular formation. By delivering LAS at nine timings (0-80 ms in 10-ms steps) relative to perturbation onset, we tested whether LAS selectively facilitates the LLR but not the short-latency reflex (SLR), and whether the facilitated epoch shifts systematically with LAS timing. In twelve healthy participants, elbow extension perturbations were applied to evoke stretch reflexes in the biceps brachii muscle. LAS produced significant supralinear facilitation in the LLR but not in the SLR. Moreover, at LAS timings of 50 ms or more after perturbation onset, LLR facilitation shifted progressively later with LAS, remaining at an approximately fixed delay of 30 ms after LAS onset. This fixed delay indicates that LAS-evoked descending input from the same origin facilitates the ongoing LLR. Together with the lack of significant SLR facilitation, this temporal pattern supports an online reticulospinal contribution to the human LLR, alongside the established corticospinal contribution. This approach provides a new, non-invasive means to investigate the physiological role of the reticulospinal tract in human motor control. Key PointsO_LIThe long-latency reflex is a rapid muscle response to sudden stretch. Unlike faster spinal reflexes, it is shaped by commands descending from the brain and adjusts to the task. C_LIO_LIThough the corticospinal tract is known to shape this reflex, whether the reticulospinal tract also contributes to the reflex has not been tested in humans. C_LIO_LIWe stretched the arm and, at various delays, played a loud sound that engages the brainstem origin of the reticulospinal tract. The sound significantly enhanced the long-latency reflex, whereas no significant enhancement was detected in the faster spinal reflex. C_LIO_LIWhen the sound came 50 milliseconds or more after the stretch, the enhancement followed the sound at a stable delay, indicating that sound-evoked descending signals interacted with the ongoing reflex response. C_LIO_LIThese findings support a real-time contribution of the reticulospinal tract to the human long-latency reflex and provide a non-invasive way to study this pathway. C_LI

neuroscience↗

bioRxiv2025

Induction of meningioma stem signature via hydrogel reprogramming and application of meningioma stem cell marker CXCR4 to pathological diagnosis and treatment.

BackgroundsMeningioma accounts for about 40% of brain tumors, but there was no effective treatment for recurrent or inoperable cases. We have previously found that when cancer cells are cultured on certain hydrogels, cancer stem cells are efficiently induced in various cancer types and we named this process as hydrogel activated reprogramming (HARP) phenomenon. In this study, we aimed to identify a key molecule that induced meningioma stem cells via hydrogels. MethodsMeningioma cells cultured on hydrogels were analyzed for expression of regular stem cell markers and their tumor genericity. Microarray analysis was performed to identify meningioma stem cell specific markers and to examine the application of such marker molecules as a therapeutic targets or pathological diagnosis for grading. ResultsRegular stem cell markers such as Nanog, and Oct3/4 were induced by culturing meningioma cells on hydrogels, and comprehensive gene expression analysis identified molecules involved in cancer stem cell activity. Among them, CXCR4 was selected as a therapeutic target molecule. Stimulation of CXCR4 via CXCL12 led to an increase in stem cell markers. In human meningioma pathological specimens and cultured cell lines, there was a correlation between CXCR4 expression levels and NF2 mutations and/or deletions. CXCR4 immunohistochemistry also detected along with the brain invasion. Thus, CXCR4 immunohistochemistry may be useful to suggest typical CNS WHO grade 1 meningioma, that do not require molecular analysis. ConclusionsWe have defined meningioma stem cell signature via HARP phenomenon and identified CXCR4 with biological significance as being diagnostic target. Key PointsO_LIWe induce meningioma stem signature via Hydrogel activated reprogramming (HARP) phenomena. C_LIO_LIWe identified CXCR4 as a candidate molecule as stemness marker and therapeutic target. C_LIO_LITranslational research using pathological specimens reveal CXCR4 immunohistochemistry has been shown to play an auxiliary role in the diagnosis of meningiomas. C_LI Importance of the StudyIn addition to morphology, immunohistochemistry and gene alteration are being adopted as diagnostic criteria for CNS tumors. From CNS5 onwards, epigenetic changes such as methylation analysis are being adopted as diagnostic criteria. We induced epigenetic changes in meningioma cells and induced cancer stemness, and this technique will be of great importance in the research and diagnosis of meningioma. In addition, microarray analysis was used to select CXCR4 from the molecules that increased simultaneously during stem cell induction on the three hydrogels, and further analysis revealed that CXCR4 immunostaining may indicate the distribution of meningioma stem cells, also making it useful for diagnosis. This report will contribute to the advancement of meningioma research and diagnosis by conducting basic research and using histopathological specimens.

bioengineering↗

bioRxiv2024

Dynamic integration of cortical activity in the deep layer of the anterolateral superior colliculus

The superior colliculus (SC) receives inputs from various brain regions in a layer- and radial location-specific manner, but whether the SC exhibits location-specific dynamics remains unclear. To address this issue, we recorded the spiking activity of single SC neurons while photoactivating cortical areas in awake head-fixed Thy1-ChR2 rats. We classified 309 neurons that responded significantly into 8 clusters according to the response dynamics. Among them, neurons with monophasic excitatory responses (7-12 ms latency) that returned to baseline within 20 ms were commonly observed in the optic and intermediate gray layers of centromedial and centrolateral SC. In contrast, neurons with complex polyphasic responses were commonly observed in the deep layers of the anterolateral SC. Cross-correlation analysis suggested that the complex pattern could be only partly explained by an internal circuit of the deep gray layer. Our results indicate that medial to centrolateral SC neurons simply relay cortical activity, whereas neurons in the deep layers of the anterolateral SC dynamically integrate inputs from the cortex, SNr, CN, and local circuits. These findings suggest a spatial gradient in SC integration, with a division of labor between simple relay circuits and those integrating complex dynamics.

neuroscience↗

bioRxiv2024

The flow state is not accompanied by frontal-midline theta activity: An EEG investigation of more than 700 video gameplay sessions

People sometimes experience a "flow state"--characterized by hyperfocus, time distortion, and loss of self-awareness--during sports or video gameplay. Previous neuropsychological studies using simple laboratory tasks have reported that the flow state is associated with activation in the frontal lobe, reflected in theta (4-7 Hz) band rhythmic neural activity in medial prefrontal regions (frontal-midline theta [FMT] activity). However, the findings of previous studies might be problematic because they did not appropriately capture the neural activity associated with the flow state for the following reasons: 1) they used unfamiliar and unmotivating tasks; 2) they defined the neural basis of the flow state as neural activity occurring during tasks of optimal difficulty, disregarding trial-to-trial variations in subjective experience of the flow state; 3) the duration of the experiment or the number of trials was not sufficient to capture the rare experience of flow; or 4) they ignored individual differences in neural activities related to flow experiences. Thus, we examined the relationship between the flow state and FMT activity, recorded via scalp electroencephalography, in an experimental paradigm that addressed these four issues. First, participants played their favorite competitive video games, which they had been routinely playing. Second, task difficulty was kept as uniform as possible across trials by employing rank matching to directly examine the correlation between subjective flow level and FMT activity across trials. Third, to address the concern regarding the low frequency of the flow experience, more than 100 trials were completed over 10 days by each participant. Lastly, we adopted a within-participant statistical approach to examine individual differences in the nature of the flow experience. The results showed no correlation between FMT activity and the degree of subjective flow in six out of seven participants, contrary to previous reports. Our results challenge the conventional view that frontal lobe activity, as reflected in FMT activity, is instrumental in entering into the flow state.

neuroscience↗

bioRxiv2024

Synergistic reinforcement learning by cooperation of the cerebellum and basal ganglia

The cerebral cortex, cerebellum and basal ganglia are essential for flexible learning in mammals. Although traditionally thought to operate under different learning rules, recent evidence suggests that both the basal ganglia and the cerebellum may employ reinforcement learning mechanisms. This raises the question of how these structures coordinate when a common reward prediction error mechanism is active. To address this issue, we first examined output signals from the basal ganglia and cerebellum following the activity of the cerebral cortex. We recorded single-neuron activity from the output regions of the cerebellum and basal ganglia - the cerebellar nuclei (CN) and substantia nigra pars reticulata (SNr) - in both male and female ChR2 transgenic rats. Neurons in the CN and SNr exhibited distinct temporal response patterns; notably, the fast excitatory response in the CN, driven by mossy fiber input, was synchronized with the inhibitory response in the SNr, mediated via the direct pathway. Using these experimental findings together with connectome data, we developed both a semi-realistic spiking network model and a reservoir-based reinforcement learning model. In the latter model, successful learning depended on synaptic plasticity in both the cerebellum and basal ganglia with a temporal precision on the order of 10 ms. Furthermore, cortical {beta}-oscillations enhanced learning and optimal reinforcement learning occurred when the output of cerebellar and basal ganglia signal phase-locked at the frequency of cortical oscillation. Taken together, our results suggest that the coordinated output of the cerebellum and basal ganglia, driven by tightly tuned cortical input, underlies brain-wide synergistic reinforcement learning. Significance StatementThe cerebral cortex, cerebellum, and basal ganglia support learning. Recent research suggests that both the basal ganglia and cerebellum use a similar learning process called reinforcement learning, which involves predicting rewards. To understand how these brain regions work together, we recorded brain activity in rats while photo-stimulating the cerebral cortex. We found that two types of responses in the cerebellum and basal ganglia were synchronized, which might help activate the cerebral cortex. A computer model showed that precise timing of signals from both the cerebellum and basal ganglia is important for learning. This timing was important only when the cerebral cortex worked in a specific frequency range. Our findings suggest that coordinated brain activity enhances learning.

neuroscience↗

bioRxiv2021

Gymnasts' ability for general motor imagery evaluated by bioelectric sensorimotor rhythms

Previous psychological studies using questionnaires have consistently reported that athletes have superior motor imagery ability, both for sports-specific and sports non-specific movements. However, regarding motor imagery of sports non-specific movements, no physiological studies have demonstrated differences in neural activity between athletes and non-athletes. The purpose of the present study was to examine differences in bioelectric sensorimotor rhythms during kinesthetic motor imagery (KMI) of sports non-specific movements between gymnasts and non-gymnasts. We selected gymnasts as an example population because they are likely to have particularly superior motor imagery ability due to frequent usage of motor imagery including KMI as part of daily practice. Healthy young participants (16 gymnasts and 16 non-gymnasts) performed repeated motor execution and KMI of sports non-specific movements (wrist dorsiflexion and shoulder abduction of the dominant hand). Scalp electroencephalogram (EEG) was recorded over the contralateral sensorimotor cortex. During motor execution and KMI, sensorimotor EEG power is known to decrease in the - (8-15 Hz) and {beta}-bands (16-35 Hz), referred to as event-related desynchronization (ERD). We calculated the maximal peak of ERD both in the - (ERDmax) and {beta}-bands ({beta}ERDmax) as a measure of changes in corticospinal excitability. ERDmax was significantly greater in gymnasts, who subjectively evaluated their KMI as being more vivid, for both KMI tasks. On the other hand, {beta}ERDmax was greater in gymnasts only for shoulder abduction KMI. These findings suggest gymnasts signature of flexibly modulating sensorimotor rhythm with no movements, which may be the basis of their superior ability of KMI for sports non-specific movements. New & NoteworthyKinesthetic motor imagery of sports non-specific movements was compared between gymnasts and non-gymnasts (i.e., healthy controls) from both physiological and psychological approaches. The EEG sensorimotor rhythms during kinesthetic motor imagery were more desynchronized in gymnasts who subjectively imaged their own movements as being more vivid. The work reveals novel ability in gymnasts to flexibly control their sensorimotor rhythms with no actual movements, which would be the basis of their superior ability of motor imagery.

neuroscience↗