Effect of Moving Tactile Stimuli to Mimic Altered Weight Distribution During Gait on Quiet Stance Body Sway.

Our purpose in the present study was to examine whether moving tactile stimuli to the sole to mimic moving weight distribution over the feet during gait would influence body sway in quiet stance. Fifteen healthy males maintained the quiet stance, and we delivered moving tactile stimuli to mimic the change in their weight distribution during gait. Moving tactile stimuli did not change the length of the center of pressure (COP) displacement and COP position.

Tactile Perception of Right Middle Fingertip Suppresses Excitability of Motor Cortex Supplying Right First Dorsal Interosseous Muscle.

The present study examined whether tactile perception of the fingertip modulates excitability of the motor cortex supplying the intrinsic hand muscle and whether this modulation is specific to the fingertip stimulated and the muscle and hand tested. Tactile stimulation was given to one of the five fingertips in the left or right hand, and transcranial magnetic stimulation eliciting motor evoked potential in the first dorsal interosseous muscle (FDI) or abductor digiti minimi was given 200 ms after the onset of tactile stimulation. The corticospinal excitability of the FDI at rest was suppressed by the tactile stimulation of the right middle fingertip, but such suppression was absent for the other fingers stimulated and for the other muscle or hand tested.

Contribution of vision and tactile sensation on body sway during quiet stance.

[Purpose] This study examines the contribution of vision and tactile sensation on body sway during quiet stance. [Participants and Methods] Sixteen healthy participants maintained quiet stance. The mean distance between the neutral center of pressure (COP) and that at the peak deviated position, indicating how quickly humans initiate the swaying of the body back to the neutral position, was calculated (COPpeak).

Sympathetic Response to Postural Perturbation in Stance.

The purpose of the present study was to elucidate whether the sympathetic response to perturbation in stance represents multiple mental responses, whether perturbation-induced fear of fall is one of the mental responses, and whether the sympathetic response is task specific. While healthy humans maintained stance, the support surface of the feet translated in the forward or backward direction. The phasic electrodermal response (EDR), representing the sympathetic response, appeared 1-1.

Influence of the Inter-Trial Interval, Movement Observation, and Hand Dominance on the Previous Trial Effect.

Previous studies have shown that current movement is influenced by the previous movement, which is known as the previous trial effect. In this study, we investigated the influence of the inter-trial interval, movement observation, and hand dominance on the previous trial effect of the non-target discrete movement. Right-handed healthy humans abducted the index finger in response to a start cue, and this task was repeated with constant inter-trial intervals.

Current Movement Follows Previous Nontarget Movement With Somatosensory Stimulation.

This study examined whether the current movement follows the previous movement and whether this process is enhanced by somatosensory stimulation or is gated while retrieving and using the memory of the previously practiced target end point. Healthy humans abducted the index finger to a previously practiced target (target movement) or abducted it freely without aiming at the target (nontarget movement). The end point of the nontarget movement had a positive correlation with the previous nontarget movement only when somatosensory stimulation was given during the previous movement, indicating that the current nontarget movement follows the previous nontarget movement with somatosensory stimulation.

Supplementary motor area contributes to carrying previous movement information over to current movement.

The purpose of the present study was to determine the cortical areas contributing to the influence of the previous movement on the current movement. Right-handed healthy human participants abducted and then adducted the left index finger in response to a start cue. Twenty consecutive trials with 10 s intertrial intervals were performed in each trial block.

Cortical contribution to motor process before and after movement onset.

Purpose: This study determined the cortical areas contributing to the process of the reaction time (RT), movement time, onset-peak time, peak velocity and amplitude of the movement.

Methods: Eighteen healthy right-handed humans abducted the left index finger in response to a start cue with transcranial magnetic stimulation (TMS).

Results: There was a significant and positive correlation coefficient between the peak velocity and amplitude, indicating that movement velocity increases with the size of the movement to maintain the consistent time taken for the movement.

Rhythmic movement and rhythmic auditory cues enhance anticipatory postural adjustment of gait initiation.

The purpose of this study was to determine whether the rhythmic movements or cues enhance the anticipatory postural adjustment (APA) of gait initiation. Healthy humans initiated gait in response to an auditory start cue (third cue). A first auditory cue was given 8 s before the start cue, and a second auditory cue was given 3 s before the start cue.