Impact of the contraction of medial forearm muscles during grip tasks in different forearm positions on medial support at the elbow joint.

We measured the medial joint distance (MJD), activity of muscles involved in medial elbow-joint support, and grip strength, aiming to examine the supportfunction of muscles. MJD was measured in supinated and pronated positions of the forearm of 10 participants under three conditions: at rest (R), under valgus load on the elbow joint (L), and under valgus load on the elbow joint during the grip task (L-grip). Under the L-grip condition, electromyography was performed on flexor digitorum superficialis (FDS), pronator teres (PT), flexor carpi radialis (FCR), and flexor carpi ulnaris (FCU); subsequently, normalized integrated electromyograms (NIEMG) were calculated.

Time-Dependent Changes in the Structure of Calcified Fibrocartilage in the Rat Achilles Tendon-Bone Interface With Sciatic Denervation.

The enthesis transmits a physiological load from soft to hard tissue via fibrocartilage. The histological alterations induced by this physiological loading remain unclear. This study was performed to examine the histomorphological alterations in the collagen fiber bundle alignment and depth of collagen interdigitation between the calcified fibrocartilage and the bone.

Effect of transcranial static magnetic field stimulation over the sensorimotor cortex on somatosensory evoked potentials in humans.

Background: The motor cortex in the human brain can be modulated by the application of transcranial static magnetic field stimulation (tSMS) through the scalp. However, the effect of tSMS on the excitability of the primary somatosensory cortex (S1) in humans has never been examined.

Objective: This study was performed to investigate the possibility of non-invasive modulation of S1 excitability by the application of tSMS in healthy humans.

Motor cortex-evoked activity in reciprocal muscles is modulated by reward probability.

Horizontal intracortical projections for agonist and antagonist muscles exist in the primary motor cortex (M1), and reward may induce a reinforcement of transmission efficiency of intracortical circuits. We investigated reward-induced change in M1 excitability for agonist and antagonist muscles. Participants were 8 healthy volunteers.

Repeated practice of a Go/NoGo visuomotor task induces neuroplastic change in the human posterior parietal cortex: an MEG study.

The posterior parietal cortex (PPC) is strongly related to task performance by evaluating sensory cues and visually guided movements. Sensorimotor processing is improved by task repetition as indicated by reduced response time. We investigated practice-induced changes in PPC visuomotor processing during a Go/NoGo task in humans using 306-channel magnetoencephalography.

Transcranial direct current stimulation over the motor association cortex induces plastic changes in ipsilateral primary motor and somatosensory cortices.

Objective: This study was performed to elucidate whether transcranial direct current stimulation (tDCS) over the motor association cortex modifies the excitability of primary motor (M1) and somatosensory (S1) cortices via neuronal connectivity.

Methods: Anodal, cathodal, and sham tDCS (1 mA) over the left motor association cortex was applied to 10 subjects for 15 min using electrodes of two sizes (9 and 18 cm(2)). Both motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) were recorded before, immediately after, and 15 min after tDCS.

Muscle-afferent projection to the sensorimotor cortex after voluntary movement and motor-point stimulation: an MEG study.

Objective: To investigate the projection of muscle afferents to the sensorimotor cortex after voluntary finger movement by using magnetoencephalography (MEG).

Methods: The movement-evoked magnetic fields (MEFs) after voluntary index-finger extension were recorded by a 204-channel whole-head MEG system. Somatosensory-evoked magnetic fields (SEFs) were recorded after motor-point stimulation was applied to the right extensor indicis muscle by using a pair of wire electrodes.

Neuromagnetic activation of primary and secondary somatosensory cortex following tactile-on and tactile-off stimulation.

Objective: Magnetoencephalography (MEG) recordings were performed to investigate the cortical activation following tactile-on and tactile-off stimulation.

Methods: We used a 306-ch whole-head MEG system and a tactile stimulator driven by a piezoelectric actuator. Tactile stimuli were applied to the tip of right index finger.

Changes in salivary physiological stress markers induced by muscle stretching in patients with irritable bowel syndrome.

Background: Psychophysiological processing has been reported to play a crucial role in irritable bowel syndrome (IBS) but there has been no report on modulation of the stress marker chromogranin A (CgA) resulting from muscle stretching. We hypothesized that abdominal muscle stretching as a passive operation would have a beneficial effect on a biochemical index of the activity of the sympathetic/adrenomedullary system (salivary CgA) and anxiety.

Methods: Fifteen control and eighteen untreated IBS subjects underwent experimental abdominal muscle stretching for 4 min.

Cortical neuromagnetic activation accompanying two types of voluntary finger extension.

We examined the amplitude and latency of movement-related cerebral field (MRCF) waveforms, the generator and afferent feedback of movement-evoked field 1 (MEF1), and the relationship between motor field neuromagnetic activity and electromyographic activity during performance of two types of voluntary index extension. Eight healthy, right-handed male volunteers participated in this study. Experiments for each subject consisted of recording of MRCFs following two types of finger movement.

Feasibility of using surface markers for assessing motion of the thumb trapeziometacarpal joint.

Objective: The purposes of the present study were to investigate the feasibility of using a skin sensor to represent the first and third metacarpal bone, to verify that there was no significant relative motion between the skin of the third metacarpal bone and trapezium bony segment and to measure thumb metacarpal motion with respect to the hand (third metacarpal).

Design: Eight hands from fresh-frozen human cadavers were disarticulated 4 cm proximal to the wrist joint and used in this experiment.

Background: Recently, magnetic-tracking systems have been developed for the measurement of joint kinematics.

EMG-angle relationship of the hamstring muscles during maximum knee flexion.

The aim of the present study was to investigate the EMG-joint angle relationship during voluntary contraction with maximum effort and the differences in activity among three hamstring muscles during knee flexion. Ten healthy subjects performed maximum voluntary isometric and isokinetic knee flexion. The isometric tests were performed for 5 s at knee angles of 60 and 90 degrees.