We investigated the autonomic nerve activity affecting changes in bowel sounds (BS) after continuous pressure stimulation (CPS) of the lumbar region. The subjects were ten healthy young adult men. Recordings of BS were acquired from each subject using a stethoscope positioned on the left lower abdomen before and 5, 10 minutes after CPS. CPS was applied to 3.5 cm lateral from the Th12 to L2 spinous processes at 50 mmHg for 10 minutes. We then calculated the BS pressure level. Heart rate variability was also assessed using RR interval of electrocardiogram. Circulatory dynamics were measured based on blood pressure (BP). We revealed that BS power of 313 Hz increased 10 minutes after CPS was applied (BS10). The BS of 313 Hz was increased after 10 minutes in CPS. The changes in BS at 10 min after CPS directly and indirectly affected the changes in BS, LF/HF, and DBP at 5 min after CPS (CMIN = 1.214, p = 0.750, GFI = 0.941, RMSEA < 0.001). These results suggest that CPS induces intestinal peristalsis which would be effected to increased cardiac parasympathetic nerve activity and peripheral artery circulation.

We analyzed morphological variations of the Japanese scapula using 3-dimensional (3D) homologous modeling based on surface data recorded using a 3D scanner. Principal component (PC) analysis was applied to polygon mesh datasets of homologous vertices (X, Y, and Z points), which detected 20 components with a cumulative proportion at 84%. The first five components can describe approximately 50% of scapula variations in the samples used. The interpretation of these components are summarized as follows: PC1, anterior inclination of the glenoid fossa and coracoid process increased as the curvature of the scapular body increased; PC2, area of the infraspinatus fossa relative to the supraspinatus fossa increased as the vertical length of the scapular body increased; PC3, width of the supraspinatus fossa decreased with the forward tilt of the acromion; PC4, width of the supraspinatus fossa increased as the acromion overhung outward; and PC5, forward tilt from the scapular spine to the acromion. This study extracted several variations of the scapula, demonstrating the importance of comprehensively analyzing the overall shape of the scapula. We hope to elucidate the relationship between the overall scapular shape and shoulder disease using 3D homologous modeling.

Purpose: We hypothesized that the relationship between mechanical stress during development and embryonic and neonatal tendon formation in the mouse model might be applied to prevent disease and treat tendon regeneration in humans. In this study, we focused on movement, particularly exercise. This study aimed to explore changes in mechanical stress and reactions of muscle-tendon complexes.

Methods: We used Wild-type C57BL/6 mice. Motor Tests: the neurobehavioral development of the mouse pups was tested to evaluate their general motor function, including surface righting and ambulation. qPCR: The muscle and tendon responses were examined to determine the expression of genes associated with growth factor at nine-time points. Histology: For histological evaluation, the limbs were sectioned focus on the Achilles Tendon at 12 μm thickness, and stained with Alcian blue, Hematoxylin and eosin, and Picrosirius red to visualize collagen.

Results: We showed that movement is critical for the development of molecular mechanisms at different stages of growth. We captured four phases of changes in the mechanical force of the limbs. We suggest that tendon response to mechanical stimulation is fundamentally altered by biochemical signals. Collectively, these results show that the neonatal tendon development process goes through a continuous change in mechanical force followed by the expression of growth factor markers.

Conclusion: The results of this study demonstrated the importance of mechanical stress in TGF-β and Scx expression for tendon development. These findings may provide a therapeutic target for a disorder in children and tendon-related diseases.

Purpose: The purpose of this study was to use transcranial magnetic stimulation (TMS) to estimate the time period during which the supplementary motor area is active to generate anticipatory postural adjustments (APA).

Methods: Electromyograms (EMG) were recorded from the deltoid and biceps femoris muscles of eleven healthy subjects, and a reaction time task was performed by raising the right upper limb in a standing position. During the task, TMS was applied to the supplementary motor area at 0 ms, 30 ms, 50 ms, and 70 ms after the reaction sound. The trials were classified into two groups: trials in which TMS was administered in the 100-ms time period before the onset of deltoid muscle activity (APA-window) and trials with a earlier interval (APA-out). The EMG activities of the deltoid and biceps femoris muscles were also integrated to compare the muscle activities.

Results: TMS administered in the APA-window period significantly delayed the onset time of muscle activity of the biceps femoris compared to control.

Conclusion: In a standing arm raising task, the time at which the supplementary motor cortex is active to generate APAs was estimated to be within 100 ms before the onset of deltoid muscle activity.

Long-lasting exposure to stress is known to develop and aggravate chronic pain, depression, and autonomic dysfunction, although the pathological mechanisms remain to be elucidated. Social defeat stress (SDS) is one of the psychological stress associated with nociceptive hypersensitivity. In this study, we examined whether noxious chemical stimuli enhanced pain-related behaviors and neuronal activation in the spinal dorsal horn to characterize nociceptive hypersensitivity in the SDS-induced pain model. To establish the SDS model, Sprague-Dawley (SD) rats were exposed to Long-Evans (LE) rats (aggressor) for 10 min on the first day followed by indirect stress without physical contacts for 10 days. The formalin test was performed to characterize pain-related behaviors to noxious chemical stimuli (i.e., 5% formalin). Neuronal activation to the chemical stimuli was visualized using immunohistochemical staining of c-Fos-immunoreactive nuclei in the spinal dorsal horn. In the SDS model rats, the duration of pain-related behaviors induced by formalin tended to prolong in phase I, and the duration was significantly prolonged in phase II, compared to the control rats. The number of c-Fos-immunoreactive nuclei increased in laminae I–II, but not in laminae III–IV and V–VI, on the side ipsilateral to formalin injection at the spinal segments L3–L5. The numbers in the contralateral dorsal horn (laminae I–VI) were unchanged. These results demonstrate that facilitated pain-related behaviors to noxious chemical stimuli exist in a rat SDS-induced pain model, and that the hyperactivation of spinal dorsal horn neurons are associated with behavioral hypersensitivity to the stimuli.

Brain injury often causes severe motor dysfunction, which interferes with patients' independence and social life. Although injured neural circuits need to be reconstructed for functional recovery, the adult central nervous system shows limited ability to restore neuronal connections. Various therapeutic approaches, including molecular targeting and rehabilitative exercise have been investigated to promote reorganization of spared neural circuits and recovery in animal models; however, these strategies were not shown to achieve complete recovery. Therefore, a novel therapeutic concept or combinational approaches need to be developed. For example, we previously investigated src homology 2-containing phosphatase-1 (SHP-1), an inhibitor of brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signaling, as a molecule that can promote reorganization. We observed that rehabilitative exercise decreased SHP-1 and increased BDNF/TrkB expression in the spared motor cortex after brain injury in mice. Furthermore, genetic reduction of SHP-1 and rehabilitative training operate synergistically to promote reorganization of motor circuits and functional recovery. In this review, we discuss advances in therapeutic approaches and the underlying mechanisms that enhance neuronal reorganization and recovery after brain injury.

Sense of agency refers to the feeling of controlling one's actions. It acts as a “mediator” between sensory input and motor output as it can drive feedback control based on sensory feedback of movement. Sense of agency can occur using sensorimotor cues, including sensory feedback and its internal prediction or cognitive cues, such as knowledge or beliefs. The relationship between these cues is explained based on a cue integration theory in which the weight of a certain cue on the registration of agency is determined according to its relative reliability in a given situation. Based on this theory, we investigated how and which sensorimotor and cognitive cues are used for the registration of agency in motor control, thereby indicating the cue integration strategy in motor control. Accordingly, we discuss the mechanism on the registration of agency in terms of the relationship between sense of agency and motor control.

When assessing the muscle condition, maximum muscle strength is often used. However, maximum voluntary strength is always not necessary for daily activities; rather, it is important to control low-intensity muscle contraction. One of the methods to assess the ability is force steadiness, which means force fluctuation during maintaining exerted force at submaximal target value. Force fluctuation is greater in aged people or patients with neurological disorders. Force steadiness during various intensities can be evaluated by setting the target force from low- to high-intensity force level. This article focuses on relationship between ankle plantar flexor force steadiness and postural control. In healthy young adults, force steadiness at 5% of maximum voluntary contraction torque (MVT) was related to postural sway on a stable platform, and force steadiness at 20% of MVT was related to postural sway on an unstable platform. While in older adults, force steadiness at any intensity was not related postural sway on a stable platform, but force steadiness at 20% of MVT was only related to postural sway on an unstable platform. These results suggested that different postural tasks are associated with force steadiness at different intensities.

Cellular senescence, a state of irreversible cell cycle arrest, contributes to normal embryonic development and remodeling after tissue damage. On the other hand, the accumulation of senescent cells is a hallmark of aging tissues or pathological contexts and may lead to progressive tissue degeneration. The mechanisms responsible for the effects of senescent cells have not been fully elucidated. Here, we review current knowledge about the beneficial and detrimental effects of senescent cells in skeletal muscle regeneration, degeneration, and aging.

The prevalence of dementia and cognitive impairment has increased with rapid aging in Japan. Prevention of dementia has high social and clinical significance, such as maintenance of the quality of life (QOL) of the elderly themselves, and is highly expected in the field of prevention. Non-pharmacological treatments are desirable, such as nutrient intake and exercise, to maintain and improve cognitive function in middle-aged and older adults, however, no scientific evidence have been established. Therefore, we focus on the brain function called executive function which is required for decision making and problem solving in cognitive function, and the cerebral oxygenation hemodynamics in brain activity and the central arterial stiffness which decreases with age. It was clarified that LTP intake improves central artery stiffness and cerebral oxygenation hemodynamics, and that combined with aerobic exercise further improves executive function. We also found that a decrease in central artery stiffness is associated with the improvement of executive function and cerebral oxygenation hemodynamics by LTP intake and aerobic exercise intervention. Our findings suggest that habitual aerobic exercise and LTP intake in middleaged and elderly people may be effective in maintaining and improving cognitive function. These results are considered to be useful for establishing preventive measures for the onset and progression of dementia.

Patients with chronic kidney disease (CKD) have decreased physical activity and exercise tolerance because of various complications and disuse. Reduced physical activity and exercise tolerance are associated with increased mortality risk. Recently, exercise training for CKD has been reported to not only improve physical function and prognosis but also renal function. CKD rat models in some basic studies have demonstrated a renoprotective effect on exercise training. However, the detailed mechanism is unclear. We focused on renal interstitial fibrosis, which is observed in advanced CKD stages. We have reported the involvement of the renal collagen metabolism and renal renin-angiotensin system in the inhibitory effect mechanism of exercise training on renal interstitial fibrosis. Based on the results, exercise training for CKD is expected to prevent renal interstitial fibrosis and have a preventive effect on renal failure progression.