Identifying essential factors for energy-efficient walking control across a wide range of velocities in reflex-based musculoskeletal systems.

Humans can generate and sustain a wide range of walking velocities while optimizing their energy efficiency. Understanding the intricate mechanisms governing human walking will contribute to the engineering applications such as energy-efficient biped robots and walking assistive devices. Reflex-based control mechanisms, which generate motor patterns in response to sensory feedback, have shown promise in generating human-like walking in musculoskeletal models. However, the precise regulation of velocity remains a major challenge. This limitation makes it difficult to identify the essential reflex circuits for energy-efficient walking. To explore the reflex control mechanism and gain a better understanding of its energy-efficient maintenance mechanism, we extend the reflex-based control system to enable controlled walking velocities based on target speeds. We developed a novel performance-weighted least squares (PWLS) method to design a parameter modulator that optimizes walking efficiency while maintaining target velocity for the reflex-based bipedal system. We have successfully generated walking gaits from 0.7 to 1.6 m/s in a two-dimensional musculoskeletal model based on an input target velocity in the simulation environment. Our detailed analysis of the parameter modulator in a reflex-based system revealed two key reflex circuits that have a significant impact on energy efficiency. Furthermore, this finding was confirmed to be not influenced by setting parameters, i.e., leg length, sensory time delay, and weight coefficients in the objective cost function. These findings provide a powerful tool for exploring the neural bases of locomotion control while shedding light on the intricate mechanisms underlying human walking and hold significant potential for practical engineering applications.

Multimodal bipedal locomotion generation with passive dynamics via deep reinforcement learning.

Generating multimodal locomotion in underactuated bipedal robots requires control solutions that can facilitate motion patterns for drastically different dynamical modes, which is an extremely challenging problem in locomotion-learning tasks. Also, in such multimodal locomotion, utilizing body morphology is important because it leads to energy-efficient locomotion. This study provides a framework that reproduces multimodal bipedal locomotion using passive dynamics through deep reinforcement learning (DRL). An underactuated bipedal model was developed based on a passive walker, and a controller was designed using DRL. By carefully planning the weight parameter settings of the DRL reward function during the learning process based on a curriculum learning method, the bipedal model successfully learned to walk, run, and perform gait transitions by adjusting only one command input. These results indicate that DRL can be applied to generate various gaits with the effective use of passive dynamics.

Applied Improvisation Enhances the Effects of Behavioral Activation on Symptoms of Depression and PTSD in High School Students Affected by the Great East Japan Earthquake.

BACKGROUND: The education system can serve as a community-based resource to support the provision of long-term follow-up care after large-scale disasters. While school-based interventions conducted after a disaster have been confirmed to reduce symptoms of depression and posttraumatic stress disorder (PTSD), adolescents often exhibit low treatment motivation. Traditional methods used to encourage treatment motivation include fun activities, such as applied improv (AIM). This study evaluated the intervention effects and improved motivation of an intervention program combining AIM with the behavioral activation approach (BAA). METHODS: Participants were 253 tenth graders, who were in fifth grade at the time the Great East Japan Earthquake of 2011, and 239 students were included in the analyses. Participants were divided into two groups: the BAA and AIM + BAA groups. Students in each group participated in one class-wide intervention session, which lasted 60 min. Depression, PTSD symptoms, behavioral activation, avoidance, and resilience were evaluated using psychological scales. A participant's evaluations of the intervention were confirmed using the impression sheet consisting of six items that measure comprehension, difficulty, efficacy, generalization, confirmation of a specific situation, and motivation. RESULTS: A two-way analysis of variance (ANOVA) conducted using data from the psychological scale did not reveal a significant effect from the intervention program. However, the Mann-Whitney U-test, which used data from the impression sheet, showed a significant effect on comprehension (p = 0.001), generalization (p = 0.023), and motivation (p = 0.025). CONCLUSION: This study did not confirm the effectiveness of the BAA in reducing symptoms of depression and PTSD in adolescents. Regarding treatment motivation, the AIM + BAA group reported higher motivation than the BAA group. Thus, one session of AIM may contribute to improved treatment motivation in adolescents. AIM creates a safe environment and encourages engagement and participation in interventions. Treatment motivation is an important issue in adolescent therapy, and AIM may help solve this problem.

Reliability and validity of the Children's Depression Inventory-Japanese version.

BACKGROUND: Depression has major negative consequences for individuals and society, and psychological assessment tools for early disease detection are needed. The aim of this study was to investigate the reliability and validity of an updated Japanese version of the Children's Depression Inventory (CDI-J) and set a cut-off score for the detection of depression. METHODS: The participants consisted of 465 children and adolescents aged 7-17 years. The control (CON) groups consisted of students recruited from elementary and junior-high school (CONEJ) and children recruited from among hospital staff members (CONRE), while the outpatient clinical (OPC) groups consisted of pediatric psychosomatic outpatients (OPCPD) and adolescent psychiatric outpatients (OPCPS). The CON and OPC CDI-J scores underwent factor analysis using varimax rotation, followed by measurement invariance analysis. The Youth Self-Report (YSR) was administered to assess concurrent validity. The Mini-International Neuropsychiatric Interview was administered to the OPC group to diagnose current depressive symptoms. Receiver operating characteristics (ROC) analysis was conducted to evaluate case-finding performance and to set cut-off points for the detection of depression. RESULTS: The CDI-J was reliable in terms of internal consistency (Cronbach α = 0.86; mean inter-item correlation, 0.16). Re-test reliability was substantial (mean interval 18 days: γ = 0.59, P < 0.05). The four-factor solution exhibited adequate internal consistency (range, 0.52-0.73) and correspondence (Pearson correlation of 0.65 with the YSR) for both the CON and OPC groups. On ROC analysis the optimal cut-off score was 23/24. CONCLUSION: The CDI-J can be used as a reliable and well-validated instrument alongside standard diagnostic procedures.

A Brief School-Based Cognitive-Behavioral Intervention for Japanese Adolescents With Severe Posttraumatic Stress.

This pilot study investigated the efficacy of a brief school-based cognitive-behavioral intervention program for Japanese adolescents exposed to the Great East Japan Earthquake in 2011. The participants were 22 adolescents with severe posttraumatic stress symptoms at the time of the study in March 2014. They completed a single-session 4-step intervention program based on Ehlers and Clark's (2000) model at their school. Symptom status was assessed at 3 time points (preintervention, postintervention, and 4-month follow-up) using the Impact of Event Scale-Revised (Weiss, 2004) and Center for Epidemiologic Studies Depression Scale (Radloff, 1977). The results showed significant improvements in all posttraumatic stress symptoms at postintervention (d = 0.81), and the effects were maintained throughout the 4-month follow-up period (d = 1.10). However, no improvement in depressive symptoms was shown. Results from this pilot study suggest that school-based cognitive-behavioral intervention programs are feasible and show promise for Japanese adolescents with posttraumatic stress symptoms regardless of cross-cultural differences, but that additional research examining effectiveness is needed. Despite the preliminary nature of the findings of this pilot study, the strengths of our intervention were that it was driven by a well-tested theoretical model and required only a single session to administer.

The relationship between positive and negative automatic thought and activity in the prefrontal and temporal cortices: a multi-channel near-infrared spectroscopy (NIRS) study.

BACKGROUND: Recently, neurobiological studies of the cognitive model of depression have become vastly more important, and a growing number of such studies are being reported. However, the relationship between the proportion of positive and negative automatic thought and activity in the prefrontal and temporal cortices has not yet been explored. We examined the relationship between brain activity and the proportion of positive and negative automatic thought in patients with major depressive disorder (MDD), using multi-channel near-infrared spectroscopy (NIRS). METHODS: We recruited 75 individuals with MDD (36 females; mean age=39.23 ± 12.49). They completed the Hamilton Rating Scale for Depression, Automatic Thoughts Questionnaire-Revised, Japanese version of the National Adult Reading Test, and the State-Trait Anxiety Inventory. Brain activation was measured by 52-channel NIRS. RESULTS: We found that activation in the vicinity of the right superior temporal gyrus is related to a deviation to negative of the proportion of positive and negative thoughts in individuals with MDD. Left dorsolateral prefrontal cortex activity was higher in the group with comparatively frequent positive thought. LIMITATIONS: Our participants were patients taking antidepressant medication, which is known to influence brain activity. Second, the poor spatial resolution of NIRS increases the difficulty of identifying the measurement position. CONCLUSIONS: We found that activation of the prefrontal and temporal cortices is related to the proportion of automatic thoughts in the cognitive model of depression.

Frontal and right temporal activations correlate negatively with depression severity during verbal fluency task: a multi-channel near-infrared spectroscopy study.

Multi-channel near-infrared spectroscopy (NIRS) is a noninvasive, on-the-spot, functional neuroimaging technique allowing detection of the spatiotemporal characteristics of brain activity. Previous NIRS studies indicated the oxy-hemoglobin (oxy-Hb) increase during a verbal fluency task (VFT) is attenuated in patients with major depressive disorder (MDD) as compared with healthy controls. However, the possible relationship between depression symptom severity and oxy-Hb change on NIRS has not yet been elucidated. To examine this relationship, we recruited 30 patients with MDD and 30 age-, gender- and intelligence quotient-matched controls. All underwent NIRS during VFT. As expected, the oxy-Hb increase during the task was significantly smaller in patients than in controls. After false discovery rate correction using 31 channels, the mean increase in oxy-Hb during the task showed a significant negative correlation with the total score of the Hamilton Rating Scale for Depression 21-item version (ch25: rho = -.56; FDR-corrected p: .001). When each item of the HAM-D21 was examined individually, insomnia early in 9 channels (rho = -.63 to -.46; FDR corrected p: .000-.014), work and activity in 2 channels (rho = -.61 to -.57; FDR corrected p: .001 to .003) and psychomotor retardation in 12 channels (rho = -.70 to -.44; FDR corrected p: .000-.018) showed significant negative correlations with the mean oxy-Hb increase in the right frontal temporal region. Although it is possible that our results were affected by medication, these data suggest reduced right frontal temporal activation on NIRS during VFT is related to the symptom severity of MDD.