Modulation of subjective peripheral sensation, F-waves, and somatosensory evoked potentials in response to unilateral pinch task measured on the contractile and non-contractile sides.

Depression of the sensory input during voluntary muscle contractions has been demonstrated using electrophysiological methods in both animals and humans. However, the association between electrophysiological responses of the sensory system and subjective peripheral sensation (SPS) during a voluntary muscle contraction remains unclear. This study aimed to describe the changes in SPS, spinal α-motoneuron excitability (F-wave to M-wave amplitude), and somatosensory evoked potentials (SEPs) during a unilateral pinch-grip task. Outcome variables were measured on the side ipsilateral and contralateral to the muscle contraction and at rest (control). Participants were 8 healthy men aged 20.9±0.8 years. The isometric pinch-grip task was performed at 30% of the maximum voluntary isometric force measured for the right and left hands separately. The appearance rate of the F-wave during the task was significantly higher for the ipsilateral (right) hand than for the contralateral (left) hand and control condition. Although there was no difference in the F-wave latency between hands and the control condition, the amplitude of the F-wave was significantly higher for the ipsilateral (right) hand than for the contralateral (left) hand and the control condition. There was no difference in the amplitude of the SEP at N20. However, the amplitude at P25 was significantly lower for the ipsilateral (right) hand than for the contralateral (left) hand and the control condition. The accuracy rate of detecting tactile stimulation, evaluated for 20 repetitions using a Semmes-Weinstein monofilament at the sensory threshold for each participant, was significantly lower during the pinch-grip task for both the ipsilateral (right) and contralateral (left) hands than in the control condition. Overall, our findings show that SPS and neurophysiological parameters were not modulated in parallel during the task, with changes in the subjective sensation preceding changes in electrophysiological indices during the motor task. Our findings provide basic information on sensory-motor coordination.

Acute Effects of Moderate Aerobic Dance Exercise on Moods, Appetite, and Energy Intake in Young Adult Women.

Energy intake (EI) has been identified as a key factor of health controlled by exercise. Aerobic dance exercise (ADEX) is a popular exercise for fitness that one can enjoy. This present study aims to examine the influence of ADEX on moods, appetite, and EI. Thirty-one young female college students completed two 1-h experimental conditions: sedentary (SED) and ADEX followed by an ad libitum lunch. Visual analog scales and measurement of salivary α-amylase activity were used to assess appetite, fatigue, and stress at pre act, post act, and pre lunch, respectively. The rating of perceived exertion (RPE) of the SED or ADEX activities was measured using the Borg scale (range, 6-20). The participants completed the Profile of Mood States 2nd Edition-Adult Short at pre and post act only on the ADEX experimental day to assess the degree to which total mood disturbance (TMD), negative mood disturbance (NMD), and positive mood disturbance (PMD) have correlations with EI. In results, ADEX increased in RPE but did not affect TMD, NMD, PMD, hunger, fullness, appetite, and EI. Additionally, the ADEX-induced relative changes in EI were not determined to be significantly correlated with RPE in ADEX or the change in TMD, NMD, or PMD by ADEX. Our study suggests that ADEX does not affect mood, appetite, and EI. In addition, individual mood changes caused by ADEX do not correlate with EI in young adult women.

Sensory gating and suppression of subjective peripheral sensations during voluntary muscle contraction.

BACKGROUND: During voluntary muscle contraction, sensory information induced by electrostimulation of the nerves supplying the contracting muscle is inhibited and the somatosensory evoked potentials (SEPs) amplitude decreases. This depression of sensory input during voluntary muscle contraction has been demonstrated by many studies using electrophysiological methods. However, the association between the electrophysiological response of the sensory system during sustained muscle contraction and subjective peripheral sensation (SPS) is still unclear. The aim of this study was to investigate changes in spinal excitability, SEPs, and SPS during voluntary muscle contraction. RESULTS: The appearance rate of the F-wave was significantly higher during muscle contraction than rest, whereas no significant difference was observed in F-wave latency between muscle contraction and rest. Furthermore, the P25 amplitude of SEPs was significantly lower during muscle contraction than rest, whereas the N20 amplitude of SEPs exhibited no significant differences. The SPS was significantly lower during muscle contraction than rest CONCLUSIONS: We conclude that sensory gating, which is found in the P25 component of SEPs during muscle contraction, is one of the neurophysiological mechanisms underlying the suppression of SPS.

Effect of circulatory system response to motor control in one-sided contractions.

PURPOSE: The purpose of this study was to clarify the effect one-sided skeletal muscle contraction has on the circulatory system, spinal α-motoneuron excitability, and somatosensory-system-evoked potential. METHOD: Nine healthy males maintained tension at 10, 20, and 30% of maximal voluntary contraction in static gripping in right hand. Heart rate, ln high frequency (HF), blood pressure (BP), F-wave, and somatosensory-evoked potential (SEP) were recorded during gripping task. BP, F-wave and SEP were recorded from left hand (contralateral side from contracting side). RESULT AND CONCLUSION: There were significant main effects of contractions strength on heart rate (0%: 68.2 ± 6.8 bpm, 10%: 67.6 ± 7.4 bpm, 20%: 69.7 ± 8.5 bpm, 30%: 73.7 ± 9.3 bpm, F3.24=9.18, P < 0.01), systolic BP (0%: 127.7 ± 15 mmHg, 10%: 136.2 ± 13.5 mmHg, 20%: 136.2 ± 13.5 mmHg, 30%: 140.0 ± 17.1 mmHg, F3.24=23.93, P < 0.01), diastolic BP (0%: 69.3 ± 8.5 mmHg, 10%: 76.9 ± 11.1 mmHg, 20%: 79.9 ± 12.5 mmHg, 30%: 86.2 ± 14 mmHg, F3.24=17.09, P < 0.01), and F-wave appearance rate (0%: 29.7 ± 15.6%, 10%: 39.3 ± 20.5%, 20%: 47.5 ± 22.9%, 30%: 55.2 ± 21.8%, F3.24=14.04, P < 0.01). For the ln HF (0%: 5.9 ± 0.6, 10%: 6.3 ± 0.9, 20%: 6.3 ± 1.3, 30%: 6.0 ± 1.0, F3.24=2.43, P = 0.08), F-wave latency (0%: 29.6 ± 1.7 ms, 10%: 26.9 ± 2.1 ms, 20%: 26.5 ± 3.6 ms, 30%: 26.9 ± 2.3 ms, F3.24=0.11, P = 0.96), F-wave amplitude (0%: 2.0 ± 0.9%, 10%: 2.2 ± 0.9%, 20%: 2.3 ± 0.7%, 30%: 2.8 ± 1.1%, F3.24=2.80, P = 0.06), and N20 amplitude (0%: 3.9 ± 1.7 µV, 10%: 3.7 ± 1.7 µV, 20%: 3.9 ± 1.7 µV, 30%: 3.9 ± 1.8 µV, F3.24=0.61, P = 0.62), between the conditions. We conclude that regulation of the circulatory system and motor system has a limited effect on sensory input.