Biology subjects

Nakano, N.

Publications and source records attributed to Nakano, N..

4 recordsLinked to original sources

bioRxiv2024

Metabolic mode estimated by breathing reflects long-term motor memory

Respiration is a crucial metabolic process that converts macronutrients, carbohydrates and fats, and oxygen (O2) into energy and carbon dioxide (CO2) to support motor actions. In addition to the energy demands of movements, the brain is a significant energy consumer, accounting for approximately 20% of the bodys total energy expenditure and relying primarily on carbohydrates for neural activity and plasticity. However, it is not known whether O2-CO2 gas composition in breathing can serve as an indicator of neural activity and plasticity as they can for movement intensity. In the human reaching movement tasks, we evaluated time-constants of sensorimotor learning while recording O2-CO2 gas exchange. We computed the respiratory exchange ratio (RER), indicating which carbohydrate or fat is used preferentially, and found that the RER was unaffected by the execution and learning of reaching movements and that it was stable within individuals but varied across individuals. Interestingly, using computational modeling to identify short and long-time constants of sensorimotor learning, individual RER levels correlated with the magnitude of long-term, but not short-term memory. Furthermore, to experimentally manipulate the individual RER, we provided 200 kcal of glucose immediately before the task. Surprisingly, this simple intervention dramatically increased 24-hour retention by 21%. Together, the RER served as a remarkable proxy for long-term motor memory, and glucose intake shifted the physiological idling state for sensorimotor learning.

neuroscience↗

bioRxiv2024

Augmenting visual errors or variability does not enhance motor learning in remote web application tasks

Laboratory experiments employing robotic manipulandum are far from achieving their goal of helping people improve their motor learning. Remote experiments using web applications are an effective tool for bridging the gap between robotic manipulandum experiments in the laboratory and general motor tasks outside. However, the influence of interventions that increase error or variability in remote motor tasks on motor learning has not yet been determined. In this study, we aimed to elucidate the effects of interventions that visually increase errors and variability in remote experiments using web applications. In particular, 48 people participated in a web-based study on the cursor-manipulation of motor tasks using laptops. Three motor tasks (visuomotor-rotation reaching, virtual curling, and virtual ball-throwing tasks) were conducted, and each task consisted of 120 trials a day conducted for three days in this study. For each task, no intervention was provided on Day 1 and the intervention to augment motor error or variability was provided on Days 2 and 3. Differences between the groups in post-intervention test trials were examined using statistical analyses. Contrary to our expectations, the interventions of error-augmentation did not exhibit positive effects in Experiments 1 and 2, which could be attributed to a lack of haptic and proprioceptive information or inaccuracies in movement kinematics. In addition, the interventions of variability-augmentation did not exhibit positive effects in Experiment 3, which could be attributed to the complex dynamics in the relationship between perceived body movements and motor outcomes. Further research is required to identify the differences between the conditions when the interventions are effective or ineffective. Moreover, interventions must be developed to further improve general motor skills.

neuroscience↗

bioRxiv2019

Evaluation of 3D markerless motion capture accuracy using OpenPose with multiple video cameras

There is a need within human movement sciences for a markerless motion capture system, which is easy to use and suffciently accurate to evaluate motor performance. This study aims to develop a 3D markerless motion capture technique, using OpenPose with multiple synchronized video cameras, and examine its accuracy in comparison with optical marker-based motion capture. Participants performed three motor tasks (walking, countermovement jumping, and ball throwing), with these movements measured using both marker-based optical motion capture and OpenPose-based markerless motion capture. The differences in corresponding joint positions, estimated from the two different methods throughout the analysis, were presented as a mean absolute error (MAE). The results demonstrated that, qualitatively, 3D pose estimation using markerless motion capture could correctly reproduce the movements of participants. Quantitatively, of all the mean absolute errors calculated, approximately 47% were less than 20 mm and 80% were less than 30 mm. However, 10% were greater than 40 mm. The primary reason for mean absolute errors exceeding 40mm was that OpenPose failed to track the participants pose in 2D images owing to failures, such as recognition of an object as a human body segment, or replacing one segment with another depending on the image of each frame. In conclusion, this study demonstrates that, if an algorithm that corrects all apparently wrong tracking can be incorporated into the system, OpenPose-based markerless motion capture can be used for human movement science with an accuracy of 30mm or less.

neuroscience↗

bioRxiv2019

Skilled strategies of release parameters for accurate free-throw shooting in the presence of motor noise

How humans execute accurate movement in the presence of motor noise is a key problem in the field of biomechanics and motor control that limits the performance improvement in daily or sporting activities. The aim of this study was to clarify the strategy of basketball players during free-throw shooting. Two possible hypotheses were examined: the players minimize the release speed to decrease signal-dependent noise or the players maximize the shot success probability by accounting for their variability. Eight collegiate players and one professional player participated in this study by attempting shots from the free-throw line using a motion capture system. The solution manifold consisting of ball parameters at release was calculated and the optimal strategy was simulated by considering ball parameter variability; this result was compared with the actual data. Our results showed that participants selected the solution of near-minimum release speed. The deviation of the measured release angle from the minimum-speed angle was close to zero (2.8 {+/-} 3.1{degrees}). However, an increase in speed-dependent noise did not have a significant influence on the ball landing position through simulation. Additionally, the effect of release angle error on the ball landing position was minimum when using the minimum speed strategy. Therefore, the players minimize the release speed to minimize the effect of the release error on performance, instead of minimizing the speed-dependent noise itself. In other words, the strategy is \"near-minimum-speed strategy\" as well as \"minimum-error-propagation strategy\". These findings will be important for understanding how sports experts deal with intrinsic noise to improve performance.

neuroscience↗