As yawning is often observed in stressful or emotional situations such as tension and anxiety, this suggests that yawning can be considered to be an emotional behavior. However, the neural mechanisms ...underlying emotion-induced yawning remain unclear. It is well known that the hypothalamic paraventricular nucleus (PVN) is the most important brain structure for induction of yawning behavior. We previously showed that induction of yawning involves the central nucleus of the amygdala (CeA), as well as the PVN. Therefore, emotion-induced yawning could potentially be induced through activation of the direct/indirect neural pathways from the CeA to the PVN. Our present study used a combination of retrograde tracing (injection of Fluoro-Gold (FG) into the PVN) and c-Fos immunohistochemistry to examine the neural pathways that evoke emotion-induced yawning. We additionally performed lesion experiments on the CeA using ibotenic acid, a neurotoxin, to determine whether the CeA is involved in the induction of emotion-induced yawning. Emotional stress by fear conditioning induced yawning behavior, and induced expression of double-labeled cells for c-Fos and FG in the bed nucleus of the stria terminalis (BNST), but not in the CeA. Furthermore, the CeA lesions caused by ibotenic acid abolished the induction of emotion-induced yawning. These results suggest that a neural pathway from the CeA to the PVN via the BNST may be primarily involved in the induction of emotion-induced yawning behavior.
•We examined the neural pathways of emotion-induced yawning with a combination of tracing and immunohistochemistry.•Emotional stress by fear conditioning induced yawning behavior.•Indirect neural pathway from the CeA to the PVN is involved in the induction of emotion-induced yawning.•The CeA lesions caused by ibotenic acid abolished the induction of emotion-induced yawning.
•Hippocampal neuronal activation differs with exercise type of similar intensity.•Mouse hippocampal activity is activated more by treadmill than by rotarod exercise.•Exercise type is a key factor ...influencing exercise effects on the hippocampus.
The effects of exercise on the hippocampus depend on exercise conditions. Exercise intensity is thought to be a dominant factor that influences the effects of exercise on the hippocampus; however, it is uncertain whether the type of exercise influences its effectiveness. This study investigated whether the effect of an acute bout of exercise on hippocampal neuronal activation differs between two different types of exercise: treadmill and rotarod exercise. The intensities of both exercises were matched at just below the lactate threshold (LT), based on blood lactate concentration. Immunohistochemical examination of c-Fos, a marker of neuronal activation, revealed that treadmill exercise at 15 m/min (T15) significantly increased c-Fos expression in all subfields of the hippocampus (dentate gyrus DG, CA1, CA3), but rotarod exercise at 30 rpm (R30) did not, as compared with the respective control groups. These results demonstrate that moderate treadmill exercise more efficiently evokes hippocampal neuronal activation than does intensity-matched rotarod exercise. This suggests that exercise type is another important factor affecting the effects of exercise on the hippocampus.
In choral performance, a wide variety of musical expression is required to deliver the worldview of the work to the audience. Singers need to regulate their mind-body to be in the optimal state, ...which includes relaxed concentration and flexible kinesthetic controllability in sensation, expression, and vocalization, for the chorus. Therefore, a choral warm-up focused on the mind-body could be crucial for various musical expressions. However, what kind of warm-up helps the singer achieve the optimal condition for the chorus remains unclear. Here, we investigated the effects of a warm-up method focusing on breathing, physical movement, imagery, and the combination of those factors on singing performance.
Twenty-five choral singers were randomly assigned to five groups, and then singers for each group online conducted one of five warm-up conditions (breathing / stretching / imagery work / all works / control) and performed singing tasks to evaluate singing performance, including sensation, expression, and vocalization, both subjectively and objectively. Changes in mood were also measured using the second edition of the Profile of Mood States.
The results showed that the warm-up with imagery work or all works could objectively and subjectively enhance singing performance. By contrast, the warm-up with breathing or stretching did not significantly improve performance, but did enhance subjective evaluations in general. In addition, no significant correlations were found between the objective performance evaluations and changes in individual mood.
These results suggest that a warm-up focusing on mind-body interventions, especially imagery work, may enhance choral performance, thereby providing new insight for the establishment of more effective choral warm-up methods.
We examined whether artificial intelligence (AI) used with the novel digital image enhancement system modalities (CLARA+CHROMA, SPECTRA A, and SPECTRA B) could distinguish the cholesteatoma matrix, ...cholesteatoma debris, and normal middle ear mucosa, and observe the middle ear cavity during middle ear cholesteatoma surgery.
A convolutional neural network (CNN) was trained with a set of images chosen by an otologist. To evaluate the diagnostic accuracy of the constructed CNN, an independent test data set of middle ear images was collected from 14 consecutive patients with 26 cholesteatoma matrix lesions, who underwent transcanal endoscopic ear surgery at a single hospital from August 2018 to September 2019. The final test data set included 58 total images, with 1‒5 images from each modality for each case.
The CNN required only 10 s to analyze more than 58 test images. Using SPECTRA A and SPECTRA B, the CNN correctly diagnosed 15 and 15 of 26 cholesteatoma matrix lesions, with a sensitivity of 34.6% and 42.3%, and with a specificity of 81.3% and 87.5%, respectively.
Our preliminary study revealed that AI and novel imaging modalities are potentially useful tools for identifying and visualizing the cholesteatoma matrix during endoscopic ear surgery. The diagnostic ability of the CNN is not yet appropriate for implementation in daily clinical practice, based on our study findings. However, in the future, these techniques and AI tools could help to reduce the burden on surgeons and will facilitate telemedicine in remote and rural areas, as well as in developing countries where the number of surgeons is limited.
•Neuronal activities to acute exercise at different intensities were examined.•Changes in anxiety- and depressive-like behaviors by acute exercise were assessed.•Acute exercise with mild or low ...stress induces antidepressant/anxiolytic effects.
Accumulating evidence suggests that physical exercise can reduce and prevent the incidence of stress-related psychiatric disorders, including depression and anxiety. Activation of serotonin (5-HT) neurons in the dorsal raphe nucleus (DRN) is implicated in antidepressant/anxiolytic properties. In addition, the incidence and symptoms of these disorders may involve dysregulation of the hypothalamic–pituitary–adrenal axis that is initiated by corticotropin-releasing factor (CRF) neurons in the hypothalamic paraventricular nucleus (PVN). Thus, it is possible that physical exercise produces its antidepressant/anxiolytic effects by affecting these neuronal activities. However, the effects of acute physical exercise at different intensities on these neuronal activation and behavioral changes are still unclear. Here, we examined the activities of 5-HT neurons in the DRN and CRF neurons in the PVN during 30min of treadmill running at different speeds (high speed, 25m/min; low speed, 15m/min; control, only sitting on the treadmill) in male Wistar rats, using c-Fos/5-HT or CRF immunohistochemistry. We also performed the elevated plus maze test and the forced swim test to assess anxiety- and depressive-like behaviors, respectively. Acute treadmill running at low speed, but not high speed, significantly increased c-Fos expression in 5-HT neurons in the DRN compared to the control, whereas high-speed running significantly enhanced c-Fos expression in CRF neurons in the PVN compared with the control and low-speed running. Furthermore, low-speed running resulted in decreased anxiety- and depressive-like behaviors compared with high-speed running. These results suggest that acute physical exercise with mild and low stress can efficiently induce optimal neuronal activation that is involved in the antidepressant/anxiolytic effects.
•Microinjection of L-glutamate into the CeA caused the typical pattern of stereotyped yawning responses.•The CeA stimulation activated the neuronal activities of both OT and CRF neurons in the PVN, ...which are responsible for triggering yawning.•Yawning might be an emotional behavior, being based on neural mechanisms.
Yawning behavior is characterized by mouth opening accompanied by deep inspiration, as well as arousal response, and is often observed not only in states of boredom or drowsiness, but also in stressful emotional situations in humans and animals. These phenomena suggest that yawning response may be an emotional behavior, possibly through activation of the central nucleus of amygdala (CeA), which is a critical region for emotional responses. However, the involvement of the CeA in triggering yawning remains unknown. Here, we investigated whether neuronal activation of the CeA by microinjection of L-glutamate into the CeA is able to induce stereotyped yawning responses in anesthetized, spontaneously breathing rats. In addition, we assessed the effects of the CeA stimulation on the activation of oxytocin (OT) and CRF (corticotropin-releasing factor) neurons in the paraventricular nucleus of the hypothalamus (PVN), which is responsible for induction of yawning, using c-Fos immunohistochemistry. Microinjection of L-glutamate into the CeA causes an initial depressor response in the blood pressure and an arousal shift on the electrocorticogram followed by a single inspiration, which is the same as the typical pattern of the stereotyped yawning response induced by the PVN stimulation. In addition, the CeA stimulation activated the neuronal activities of both OT and CRF neurons in the PVN, as well as yawning responses. These results indicate that activation of the CeA is involved in the induction of yawning response, suggesting that yawning is an emotional behavior.
Children with Down syndrome (DS) have physical characteristics such as hypotonus of the musculature. Therefore, their attainment rate of physical activity guidelines is low, and guidelines alone may ...not be sufficient in assessing the amount of physical activity in children with DS. Compared with normal children (NC) of the same grade, light physical activity (LPA) must be considered while assessing physical activity of children with DS, owing to muscle hypotonia. This study included 69 children with DS and 68 NC in grades 4−6 attending elementary school in Japan. The measurements for physical characteristics included age, height, weight, and body mass index. Physical activity was measured using a triaxial accelerometer, which indicated physical activity volume. Children with DS had less moderate-to-vigorous physical activity duration (DS: 53.1 min/day, NC: 65.0 min/day; p < 0.001) but significantly longer LPA duration (DS: 376.4 min/day, NC: 287.7 min/day; p < 0.001) than NC. Conversely, the amount of light to vigorous physical activity (Met’s-hours/day) was greater in children with DS (DS: 16.0 Met’s-hours/day, NC: 14.4 Met’s-hours/day; p = 0.037). In children with DS with muscular hypotonia, vigorous physical activity is challenging, but LPA is feasible. Developing and validating educational programs that promote physical activity with intensity level depending on individual’s physical characteristic are warranted.
Physical exercise can improve brain function, but the effects of exercise cessation are largely unknown. This study examined the time-course profile of hippocampal neurogenesis following exercise ...cessation. Male C57BL/6 mice were randomly assigned to either a control (Con) or an exercise cessation (ExC) group. Mice in the ExC group were reared in a cage with a running wheel for 8 wk and subsequently placed in a standard cage to cease the exercise. Exercise resulted in a significant increase in the density of doublecortin (DCX)-positive immature neurons in the dentate gyrus (at
). Following exercise cessation, the density of DCX-positive neurons gradually decreased and was significantly lower than that in the Con group at 5 and 8 wk after cessation, indicating that exercise cessation leads to a negative rebound in hippocampal neurogenesis. Immunohistochemistry analysis suggests that the negative rebound in neurogenesis is caused by diminished cell survival, not by suppression of cell proliferation and neural maturation. Neither elevated expression of ΔFosB, a transcription factor involved in neurogenesis regulation, nor increased plasma corticosterone, were involved in the negative neurogenesis rebound. Importantly, exercise cessation suppressed ambulatory activity, and a significant correlation between change in activity and DCX-positive neuron density suggested that the decrease in activity is involved in neurogenesis impairment. Forced treadmill running following exercise cessation failed to prevent the negative neurogenesis rebound. This study indicates that cessation of exercise or a decrease in physical activity is associated with an increased risk for impaired hippocampal function, which might increase vulnerability to stress-induced mood disorders.
Physical exercise improves multiple aspects of hippocampal function. In line with the notion that neuronal activity is key to promoting neuronal functions, previous literature has consistently ...demonstrated that acute bouts of exercise evoke neuronal activation in the hippocampus. Repeated activating stimuli lead to an accumulation of the transcription factor ΔFosB, which mediates long-term neural plasticity. In this study, we tested the hypothesis that long-term voluntary wheel running induces ΔFosB expression in the hippocampus, and examined any potential region-specific effects within the hippocampal subfields along the dorso-ventral axis. Male C57BL/6 mice were housed with or without a running wheel for 4 weeks. Long-term wheel running significantly increased FosB/ΔFosB immunoreactivity in all hippocampal regions measured (i.e., in the DG, CA1, and CA3 subfields of both the dorsal and ventral hippocampus). Results confirmed that wheel running induced region-specific expression of FosB/ΔFosB immunoreactivity in the cortex, suggesting that the uniform increase in FosB/ΔFosB within the hippocampus is not a non-specific consequence of running. Western blot data indicated that the increased hippocampal FosB/ΔFosB immunoreactivity was primarily due to increased ΔFosB. These results suggest that long-term physical exercise is a potent trigger for ΔFosB induction throughout the entire hippocampus, which would explain why exercise can improve both dorsal and ventral hippocampus-dependent functions. Interestingly, we found that FosB/ΔFosB expression in the DG was positively correlated with the number of doublecortin-immunoreactive (i.e., immature) neurons. Although the mechanisms by which ΔFosB mediates exercise-induced neurogenesis are still uncertain, these data imply that exercise-induced neurogenesis is at least activity dependent. Taken together, our current results suggest that ΔFosB is a new molecular target involved in regulating exercise-induced hippocampal plasticity.
Hot corrosion tests of alumina (Al2O3) and carbon silicate (SiC) ceramics exposed to KCl–NaCl molten salt were performed at high temperatures (700 and 800°C) and for long times (100–400 h) in order ...to improve the reliability of tanks and heat exchangers for molten salts. The samples were tested by being immersed in molten salt and under salt vapor. Basic corrosion data, such as the corrosion product, surface conditions, and 4-point bending strength were acquired. In the case of the Al2O3 ceramics, neither corrosion products nor a significant roughness of the Al2O3 particles was observed. In the case of the SiC ceramics, the observed corrosion product was SiO2, and considerable roughness was found at the surface of the immersed sample. The surface roughness became more pronounced as the corrosion temperature and time increased. On the other hand, a SiO2 thin film was observed on the surface of the sample that was exposed to salt vapor. A significant strength decrease was not observed for the two types of Al2O3 and SiC ceramics. Therefore, Al2O3 ceramics are expected to represent a suitable container material for molten salts. On the other hand, predicting the lifetime of the material is necessary if SiC ceramics are intended to be used.
PDF
