Comparing movement-related cortical potential between real and simulated movement tasks from an ecological validity perspective.

Introduction: Concerns regarding the ecological validity of movement-related cortical potential (MRCP) experimental tasks that are related to motor learning have recently been growing. Therefore, we compared MRCP during real movement task (RMT) and simulated movement task (SMT) from an ecological validity perspective.

Methods: The participants performed both RMT and SMT, and MRCP were measured using electroencephalogram (EEG).

Somatosensory temporal discrimination threshold changes during motor learning.

Purpose: Mechanisms underlying the somatosensory temporal discrimination threshold and its relationship with motor control have been reported; however, little is known regarding the change in temporal processing of tactile information during motor learning. We investigated the somatosensory temporal discrimination threshold changes during motor learning in a feedback-control task.

Materials And Methods: We included 15 healthy individuals.

Increasing corticospinal excitability in the antagonist muscle during muscle relaxation with a tracking task.

The present study aimed to investigate corticospinal excitability changes during muscle relaxation with a tracking task. The motor-evoked potential, which was elicited from the flexor carpi radialis (agonist) and extensor carpi radialis (antagonist) muscles, was analyzed in terms of both the relaxation velocity and phase. Our results suggest that increasing corticospinal excitability in the antagonist muscle plays an important role in controlling the relaxation of the agonist muscle during gradual relaxation with a tracking task.

Combined effect of motor imagery and peripheral nerve electrical stimulation on the motor cortex.

Although motor imagery enhances the excitability of the corticospinal tract, there are no peripheral afferent inputs during motor imagery. In contrast, peripheral nerve electrical stimulation (ES) can induce peripheral afferent inputs; thus, a combination of motor imagery and ES may enhance the excitability of the corticospinal tract compared with motor imagery alone. Moreover, the level of stimulation intensity may also be related to the modulation of the excitability of the corticospinal tract during motor imagery.

Real-time changes in corticospinal excitability during voluntary contraction with concurrent electrical stimulation.

While previous studies have assessed changes in corticospinal excitability following voluntary contraction coupled with electrical stimulation (ES), we sought to examine, for the first time in the field, real-time changes in corticospinal excitability. We monitored motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation and recorded the MEPs using a mechanomyogram, which is less susceptible to electrical artifacts. We assessed the MEPs at each level of muscle contraction of wrist flexion (0%, 5%, or 20% of maximum voluntary contraction) during voluntary wrist flexion (flexor carpi radialis (FCR) voluntary contraction), either with or without simultaneous low-frequency (10 Hz) ES of the median nerve that innervates the FCR.