Evidence for a common mechanism supporting invigoration of action selection and action execution.

The speed, or vigor, of our movements can vary depending on circumstances. For instance, the promise of a reward leads to faster movements. Reward also leads us to move with a lower reaction time, suggesting that the process of action selection can also be invigorated by reward.

De novo motor learning of a bimanual control task over multiple days of practice.

Although much research on motor learning has focused on how we adapt our movements to maintain performance in the face of imposed perturbations, in many cases, we must learn new skills from scratch or de novo. Compared with adaptation, relatively little is known about de novo learning. In part, this is because learning a new skill can involve many challenges, including learning to recognize new patterns of sensory input and generate new patterns of motor output.

Aberrant Cerebello-Cortical Connectivity in Pianists With Focal Task-Specific Dystonia.

Musician's dystonia is a type of focal task-specific dystonia (FTSD) characterized by abnormal muscle hypercontraction and loss of fine motor control specifically during instrument playing. Although the neuropathophysiology of musician's dystonia remains unclear, it has been suggested that maladaptive functional abnormalities in subcortical and cortical regions may be involved. Here, we hypothesized that aberrant effective connectivity between the cerebellum (subcortical) and motor/somatosensory cortex may underlie the neuropathophysiology of musician's dystonia.

Neuroanatomical Basis of Individuality in Muscle Tuning Function: Neural Correlates of Muscle Tuning.

In a conventional view of motor control, the human brain might employ an optimization principle that leads a stereotypical motor behavior which we observe as an averaged behavioral data over subjects. In this scenario, the inter-individual motor variability is considered as an observation noise. Here, we challenged this view.

Distinct roles of brain activity and somatotopic representation in pathophysiology of focal dystonia.

Two main neural mechanisms including loss of cortical inhibition and maladaptive plasticity have been thought to be involved in the pathophysiology of focal task-specific dystonia. Such loss of inhibition and maladaptive plasticity likely correspond to cortical overactivity and disorganized somatotopy, respectively. However, the most plausible mechanism of focal task-specific dystonia remains unclear.

Resting-state basal ganglia network codes a motor musical skill and its disruption From dystonia.

Background: Musician's dystonia critically impacts professional musicians' careers as they may lose musical skills, which have been acquired through long and intensive training. Yet the pathophysiology of musician's dystonia and its link to the neural mechanisms supporting musical skills is poorly understood. We tested if resting-state functional connectivity might reflect an aspect of musical skill linked to the pathophysiology of musician's dystonia.

Decoding of Ankle Flexion and Extension from Cortical Current Sources Estimated from Non-invasive Brain Activity Recording Methods.

The classification of ankle movements from non-invasive brain recordings can be applied to a brain-computer interface (BCI) to control exoskeletons, prosthesis, and functional electrical stimulators for the benefit of patients with walking impairments. In this research, ankle flexion and extension tasks at two force levels in both legs, were classified from cortical current sources estimated by a hierarchical variational Bayesian method, using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) recordings. The hierarchical prior for the current source estimation from EEG was obtained from activated brain areas and their intensities from an fMRI group (second-level) analysis.

New portable voice guidance device for the manual wheelchair transfer: a pilot study in patients with hemiplegia.

Purpose: Older and/or cognitively impaired patients require verbal guidance to prevent accidents during wheelchair operation, thus increasing the burden on caregivers. This study aimed to develop a new portable voice guidance device for manual wheelchairs and examine its clinical usefulness.

Method: We developed a portable voice guidance device to monitor the statuses of wheelchair brakes and footrests and automatically provide voice guidance for operation.

Designing and testing lightweight shoulder prostheses with hybrid actuators for movements involved in typical activities of daily living and impact absorption.

Unlike forearm amputees, transhumeral amputees have residual stumps that are too small to provide a sufficient range of operation for their prosthetic parts to perform usual activities of daily living. Furthermore, it is difficult for small residual stumps to provide sufficient impact absorption for safe manipulation in daily living, as intact arms do. Therefore, substitution of upper limb function in transhumeral amputees requires a sufficient range of motion and sufficient viscoelasticity for shoulder prostheses under critical weight and dimension constraints.

Designing and testing a hybrid lightweight shoulder prosthesis.

Lightweight prostheses are preferred in terms of usability in daily living. However, this is not a property easy to realize, especially for shoulder prostheses. High portability, multiple degrees of freedom (DOFs) with an appropriate ROM (range of motion), sufficient end-effector power, and suitable viscoelasticity for the safe use in daily living, usually result in a heavy weight.

Development of a small sucker manipulator for underwater surgery support.

WaFLES (Water-Filled LaparoEndoscopic Surgery) is an operative method suggested by Igarashi et al., which has several advantages, such as, preventing the drying of inner organs, and being able to use ultrasound devices for real time monitoring. However, grasping of inner organs with usual forceps for move and incision purpose is difficult.

Ultrasound imaging and semi-automatic analysis of active muscle features in electrical stimulation by optical flow.

Ultrasound imaging is an effective way to measure the muscle activity in electrical stimulation studies. However, it is a time consuming task to manually measure pennation angle and muscle thickness, which are the benchmark features to analyze muscle activity from the ultrasound imaging. In previous studies, the muscle features were measured by calculating optical flow of the pennation angle by using only fibers of a muscle from the ultrasound, without carefully considering moving muscle edges during active and passive contraction.

A pilot study of sensory feedback by transcutaneous electrical nerve stimulation to improve manipulation deficit caused by severe sensory loss after stroke.

Background: Sensory disturbance is common following stroke and can exacerbate functional deficits, even in patients with relatively good motor function. In particular, loss of appropriate sensory feedback in severe sensory loss impairs manipulation capability. We hypothesized that task-oriented training with sensory feedback assistance would improve manipulation capability even without sensory pathway recovery.

A sensory feedback system utilizing cutaneous electrical stimulation for stroke patients with sensory loss.

Sensory disturbance is very common following stroke and may exacerbate a patient's functional impairment, even if the patient has good motor function. For instance, patients with sensory disturbances will often grip an object with excessive or underestimated pinch pressure, because they do not receive the appropriate sensory feedback and must rely only on visual feedback. In this study, we developed a sensory feedback system that used cutaneous electrical stimulation for patients with sensory loss.

Single session of transcranial direct current stimulation transiently increases knee extensor force in patients with hemiparetic stroke.

Background: Transcranial direct current stimulation (tDCS) of the motor cortex can enhance the performance of a paretic upper extremity after stroke. Reported effects on lower limb (LL) function are sparse.

Objective: The authors examined whether tDCS can increase the force production of the paretic quadriceps.

Evaluation method for the proficiency level of an operating myoelectric hand using EMG signals.

To evaluate the proficiency level of an operating myoelectric hand, we proposed an evaluation index consisting of the accuracy and the reproducibility of electromyography (EMG) signal patterns. Our proposed method is not an absolute evaluation because we use bio-signals, so it is necessary to verify the correlation between the proposed index and performance evaluation to confirm the usefulness of the index. Therefore, we conducted classification tests on eight forearm motions and verified the correlation between the proposed method and the classification rate.

Self-organized clustering approach for motion discrimination using EMG signal.

In order to control a myoelectric hand, it is necessary to discriminate among motions using electromyography (EMG) signals. One of the biggest problems in doing so is that EMG feature patterns of different motions overlap, and a classifier cannot discriminate clearly between them. Therefore, we propose a motion discrimination method to solve this problem.

Motion classification using epidural electrodes for low-invasive brain-machine interface.

Brain-machine interfaces (BMIs) are expected to be used to assist seriously disabled persons' communications and reintegrate their motor functions. One of the difficult problems to realize practical BMI is how to record neural activity clearly and safely. Conventional invasive methods require electrodes inside the dura mater, and noninvasive methods do not involve surgery but have poor signal quality.

Control strategy for a myoelectric hand: measuring acceptable time delay in human intention discrimination.

In order to enhance controllability of a myoelectric hand, we focus on a gap between the time when a human intends to move a myoelectric hand and the time when the hand actually moves (i.e., time delay).