scholarly journals Stand Up to Excite the Spine: Neuromuscular, Autonomic, and Cardiometabolic Responses During Motor Imagery in Standing vs. Sitting Posture

2021 ◽  
Vol 12 ◽  
Author(s):  
Sidney Grosprêtre ◽  
Uros Marusic ◽  
Philippe Gimenez ◽  
Gael Ennequin ◽  
Laurent Mourot ◽  
...  
Keyword(s):  
Motor Imagery ◽  
Motor Command ◽  
Triceps Surae ◽  
Body Sway ◽  
Sitting Posture ◽  
Parasympathetic System ◽  
Before And After ◽  
And Performance ◽  
The Right ◽  
Spinal Excitability

Motor imagery (MI) for health and performance strategies has gained interest in recent decades. Nevertheless, there are still no studies that have comprehensively investigated the physiological responses during MI, and no one questions the influence of low-level contraction on these responses. Thus, the aim of the present study was to investigate the neuromuscular, autonomic nervous system (ANS), and cardiometabolic changes associated with an acute bout of MI practice in sitting and standing condition. Twelve young healthy males (26.3 ± 4.4 years) participated in two experimental sessions (control vs. MI) consisting of two postural conditions (sitting vs. standing). ANS, hemodynamic and respiratory parameters, body sway parameters, and electromyography activity were continuously recorded, while neuromuscular parameters were recorded on the right triceps surae muscles before and after performing the postural conditions. While MI showed no effect on ANS, the standing posture increased the indices of sympathetic system activity and decreased those of the parasympathetic system (p < 0.05). Moreover, MI during standing induced greater spinal excitability compared to sitting posture (p < 0.05), which was accompanied with greater oxygen consumption, energy expenditure, ventilation, and lower cardiac output (p < 0.05). Asking individuals to perform MI of an isometric contraction while standing allows them to mentally focus on the motor command, not challenge balance, and produce specific cardiometabolic responses. Therefore, these results provide further evidence of posture and MI-related modulation of spinal excitability with additional autonomic and cardiometabolic responses in healthy young men.

scholarly journals Effect of reflexive activation of motor units on torque development during electrically-evoked contractions of the triceps surae muscle

2019 ◽  
Vol 126 (2) ◽  
pp. 386-392 ◽  
Author(s):  
Florian Vitry ◽  
Alain Martin ◽  
Gaëlle Deley ◽  
Maria Papaiordanidou
Keyword(s):  
Tibial Nerve ◽  
Motor Evoked Potential ◽  
Motor Units ◽  
Triceps Surae ◽  
Emg Activity ◽  
Main Role ◽  
Frequency Dependent ◽  
Before And After ◽  
Spinal Excitability ◽  
Torque Development

The aim of the study was to identify stimulation conditions permitting the occurrence of extra torque (ET) and to examine their impact on spinal and corticospinal excitabilities. Twelve subjects received stimulation trains over the tibial nerve (20 s duration, 1 ms pulse duration) that were delivered at 3 stimulation frequencies (20, 50, and 100 Hz) and at 5 intensities (110%, 120%, 130%, 140%, and 150% of the motor threshold). Torque-time integral (TTI) of each stimulation train was calculated. Spinal [maximum H-reflex (Hmax)/maximal M-wave (Mmax)] and corticospinal [maximal motor evoked potential amplitude (MEPmax)/Mmax] excitabilities were assessed at rest before and after each stimulation train by tibial nerve stimulation and by transcranial magnetic stimulation, respectively. Moreover, a twitch at each stimulation intensity was delivered before and after each stimulation train. The EMG activity associated with this twitch was analyzed to identify the initial motor unit (MU) recruitment pathway before each stimulation train and discriminate trials to H-trials (indirect recruitment) and M-trials (direct recruitment). TTI was higher for H-trials compared with M-trials for all tested frequencies. There was a decrease in Hmax/Mmax for the 20 Hz-H trials and an increase for the 100 Hz-H trials, whereas MEPmax/Mmax remained unchanged at post measurements. Present results demonstrate that the initial MU recruitment pattern plays a main role in the ET occurrence, with the indirect recruitment via the afferent volley being substantial for its development. The modulations of Hmax/Mmax without changes in MEPmax/Mmax suggest that the ET development affects spinal excitability and that these changes are frequency dependent. NEW & NOTEWORTHY This study brings new insights into the stimulation conditions permitting the development of extra torque. An initial indirect recruitment of motor units, inducing reflex activation of spinal neurons through Ia afferent solicitation, appears a prerequisite for extra torque development. Under these conditions, spinal excitability modulations were frequency dependent.

Sound localization after transection of the commissure of Probst in the albino rat

1996 ◽  
Vol 76 (5) ◽  
pp. 3493-3502 ◽  
Author(s):  
M. Ito ◽  
B. van Adel ◽  
J. B. Kelly
Keyword(s):  
Brain Stem ◽  
Sound Localization ◽  
Noise Burst ◽  
Broadband Noise ◽  
Albino Rat ◽  
Retrograde Degeneration ◽  
Cell Counts ◽  
Before And After ◽  
And Performance ◽  
The Right

1. The ability of rats to localize sounds in space was determined before and after cutting of the commissure of Probst. The commissure of Probst was transected at its midline decussation with a microknife inserted into the brain according to stereotaxic coordinates. Six animals were tested after extensive lesions that destroyed all of the commissure of Probst fibers. An additional animal was tested after a smaller lesion that destroyed most of the commissure of Probst but left some fibers intact. Three control animals were tested before and after surgical intervention that did not involve the commissure of Probst. 2. The animals were tested in a semicircular apparatus with loudspeakers located on the right or left of midline. They were trained to make a response toward the left or right in the direction of the active loudspeaker. Correct reponses were rewarded by delivery of a small quantity of water from spouts located at +30 and -30 degrees azimuth. Tests of sound localization were conducted with a single broadband noise burst, 45 ms in duration, presented at the beginning of each trial. The position of the active loudspeakers was varied from trial to trial and performance at different speaker angles was calculated to determine psychometric curves. Minimum audible angles were estimated by interpolation from a performance level of 75% correct. 3. After postoperative testing was completed, the effectiveness of the lesions was confirmed by cell counts to determine the extent of retrograde degeneration in the dorsal nucleus of the lateral lemniscus (DNLL). These data showed that most of the contralaterally projecting neurons in DNLL underwent retrograde degeneration and the number of neurons was reduced by 60-65%. Ninety to 95% of the contralaterally projecting neurons in the DNLL disappeared within 7 wk after transection of the commissure of Probst. 4. The condition of damaged commissural fibers was further confirmed by tract tracing methods. A unilateral Fluoro-Gold injection was made into the inferior colliculus and the auditory brain stem was examined for retrograde label. No labeled neurons were seen in the contralateral DNLL in cases with complete transection of the commissure of Probst. In addition, the distribution of Fluoro-Gold labeling in other brain stem auditory structures was similar to that seen in normal animals. This result confirmed that the transection of the commissure of Probst was successful and that projections to other auditory structures remained intact. 5. Transection of the commissure of Probst produced marked deficits in midline sound localization. Although sound localization was still possible, there was a degradation in the ability of rats to localize sounds in the horizontal plane. The mean minimum audible angle was elevated 22.1 degrees after destruction of the commissure of Probst compared with a shift of only 2.0 degrees in control animals.

scholarly journals SENSORIMOTOR POTENTIATION OF MOTOR IMAGINATION AS CNS PLASTICITY ACTIVATOR

2016 ◽  
Vol 1 (3) ◽  
pp. 33-38
Author(s):  
E S Korovina ◽  
E N Glazkova ◽  
I V Shirolapov ◽  
O G Kuznetsova ◽  
N R Khanbikov ◽  
...  
Keyword(s):  
Left Hemisphere ◽  
Motor Imagery ◽  
Sensorimotor Cortex ◽  
Motor Pattern ◽  
Elbow Flexion ◽  
Recording System ◽  
Eeg Rhythms ◽  
Before And After ◽  
Alpha Beta ◽  
The Right

Aim - to find out the neurophysiological correlatives of motor imagery after the simulation of the motor pattern. Materials and methods. Monopolar EEG was recorded using EEG recording system Neuron - Spectrum - 4 / VPM at 7 right-handed volunteers aged 18-19 years. EEG was recorded according to the system 10-5 in the projection of the sensorimotor cortex of the left hemisphere during the imagination of two movements in the right hand (flexing the fingers, elbow flexion) before and after 30 seconds of simulation of movement patterns using the rehabilitation device Power Plate. Results. After the simulation of the motor pattern, the imagination of the two types of movement correlated with desynchronization of alpha-, beta- EEG rhythms, increasing the number of leads with the reaction of desynchronization (p

scholarly journals An acute session of motor imagery training induces use-dependent plasticity

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Célia Ruffino ◽  
Jérémie Gaveau ◽  
Charalambos Papaxanthis ◽  
Florent Lebon
Keyword(s):  
Motor Imagery ◽  
Primary Motor Cortex ◽  
Corticospinal Excitability ◽  
Movement Direction ◽  
Control Group ◽  
Dependent Plasticity ◽  
Imagery Training ◽  
Imagery Group ◽  
Before And After ◽  
The Right

AbstractMotor imagery, defined as the mental representation of an action without movement-related sensory inputs, is a well-known intervention to improve motor performance. In the current study, we tested whether use-dependent plasticity, a mechanism underlying motor learning, could be induced by an acute session of motor imagery. By means of transcranial magnetic stimulation (TMS) over the left primary motor cortex, we evoked isolated thumb movements in the right hand and assessed corticospinal excitability in the flexor and extensor pollicis brevis muscles. We measured the mean TMS-induced movement direction before and after an acute session of motor imagery practice. In a first experiment, participants of the imagery group were instructed to repeatedly imagine their thumb moving in a direction deviated by 90° from the pre-test movement. This group, but not the control group, deviated the post-training TMS-induced movements toward the training target direction (+44° ± 62° and −1° ± 23°, respectively). Interestingly, the deviation magnitude was driven by the corticospinal excitability increase in the agonist muscle. In a second experiment, we found that post-training TMS-induced movements were proportionally deviated toward the trained direction and returned to baseline 30 minutes after the motor imagery training. These findings suggest that motor imagery induces use-dependent plasticity and, this neural process is accompanied by corticospinal excitability increase in the agonist muscle.

scholarly journals An acute session of motor imagery training induces use-dependent plasticity

2019 ◽  
Author(s):  
Célia Ruffino ◽  
Jérémie Gaveau ◽  
Charalambos Papaxanthis ◽  
Florent Lebon
Keyword(s):  
Motor Imagery ◽  
Primary Motor Cortex ◽  
Corticospinal Excitability ◽  
Movement Direction ◽  
Control Group ◽  
Dependent Plasticity ◽  
Imagery Training ◽  
Imagery Group ◽  
Before And After ◽  
The Right

AbstractMotor imagery, defined as the mental representation of an action without movement-related sensory inputs, is a well-known intervention to improve motor performance. In the current study, we tested whether use-dependent plasticity, a mechanism underlying motor learning, could be induced by an acute session of motor imagery. By means of transcranial magnetic stimulation (TMS) over the left primary motor cortex, we evoked isolated thumb movements in the right hand and assessed corticospinal excitability in the flexor and extensor pollicis brevis muscles. We measured the mean TMS-induced movement direction before and after an acute session of motor imagery practice. In a first experiment, participants of the imagery group were instructed to repeatedly imagine their thumb moving in a direction deviated by 90° from the pre-test movement. This group, but not the control group, deviated the post-training TMS-induced movements toward the training target direction (+44° ±62° and −1° ±23°, respectively). Interestingly, the deviation magnitude was driven by the corticospinal excitability increase in the agonist muscle. In a second experiment, we found that post-training TMS-induced movements were proportionally deviated toward the trained direction and returned to baseline 30 minutes after the motor imagery training. These findings suggest that motor imagery induces use-dependent plasticity and, this neural process is accompanied by corticospinal excitability increase in the agonist muscle.

scholarly journals THE USE OF DIETARY SUPPLEMENTS IN SPORTS NUTRITION AND VIEW OF THEIR EFFECT ON PERFORMANCE

2020 ◽  
Vol 36 ◽  
pp. 0-0
Author(s):  
Çağla ALBAY ◽  
Burcu YEŞİLKAYA
Keyword(s):  
Sports Nutrition ◽  
Activity Level ◽  
Healthy Nutrition ◽  
Body Development ◽  
Energy Needs ◽  
Before And After ◽  
And Performance ◽  
The Right ◽  
Supplementary Foods ◽  
Body Fluid Balance

Aim: This study was prepared to investigate the effect of nutritional ergogenic supplements used by people who do sports on their body development in various sports branches. Methods: This review was prepared by compiling the studies on sports nutrition and supplementary foods used in sports nutrition in the last 15 years.Results: Genetic structure, appropriate training and nutrition are the primary factors affect the performance of athletes. The energy needs of athletes differ according to their age, gender, physical activity level and amount of the energy spent. The main factors should be considered in the nutritıon of each athlete must be ensuring the continuity of health and performance, consuming energy and nutrients adeqately, choosing the right food before and after the exercises, establishing continuity in body fat and leaning mass percentage according to the kind of sport performed and ensuring recovery and body fluid balance after training. In recent years, nutritional ergogenic aid has become widespread among athletes at different levels in order to increase the performance and achieve success more easily besides nutrition. As a result of reserarches and clinical trials, espicially glutamine, caffeine, creatine, vitamin and mineral supplements are allowed to be used in correct amounts and proporstions. Conclusion: Studies on Sports Nutrition and their scope are developing day by day. After the foundation of healthy nutrition is established, the sports process is supported with nutritional supplements, provided that the latest literature studies on this subject are followed.

scholarly journals Corticospinal and Spinal Excitabilities Are Modulated during Motor Imagery Associated with Somatosensory Electrical Nerve Stimulation

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
E. Traverse ◽  
F. Lebon ◽  
A. Martin
Keyword(s):  
Motor Imagery ◽  
Nerve Stimulation ◽  
Motor Evoked Potentials ◽  
Plantar Flexion ◽  
Mental Simulation ◽  
Somatosensory Stimulation ◽  
Electrical Nerve Stimulation ◽  
Time Specific ◽  
The Right ◽  
Spinal Excitability

Motor imagery (MI), the mental simulation of an action, influences the cortical, corticospinal, and spinal levels, despite the lack of somatosensory afferent feedbacks. The aim of this study was to analyze the effect of MI associated with somatosensory stimulation (SS) on the corticospinal and spinal excitabilities. We used transcranial magnetic stimulation and peripheral nerve stimulation to induce motor-evoked potentials (MEP) and H-reflexes, respectively, in soleus and medialis gastrocnemius (MG) muscles of the right leg. Twelve participants performed three tasks: (1) MI of submaximal plantar flexion, (2) SS at 65 Hz on the posterior tibial nerve with an intensity below the motor threshold, and (3) MI + SS. MEP and H-reflex amplitudes were recorded before, during, and after the tasks. Our results confirmed that MI increased corticospinal excitability in a time-specific manner. We found that MI+SS tended to potentiate MEP amplitude of the MG muscle compared to MI alone. We confirmed that SS decreased spinal excitability, and this decrease was partially compensated when combined with MI, especially for the MG muscle. The increase of CSE could be explained by a modulation of the spinal inhibitions induced by SS, depending on the amount of afferent feedbacks.

scholarly journals The Neural Specificity of Movement Preparation During Actual and Imagined Movements

2018 ◽  
Vol 29 (2) ◽  
pp. 689-700 ◽  
Author(s):  
Florent Lebon ◽  
Célia Ruffino ◽  
Ian Greenhouse ◽  
Ludovica Labruna ◽  
Richard B Ivry ◽  
...  
Keyword(s):  
Motor Imagery ◽  
Corticospinal Excitability ◽  
Delayed Response ◽  
Movement Preparation ◽  
Actual Movement ◽  
Before And After ◽  
First Dorsal Interosseous Muscle ◽  
Response Task ◽  
The Right ◽  
Imagined Movement

Abstract Current theories consider motor imagery, the mental representation of action, to have considerable functional overlap with the processes involved in actual movement preparation and execution. To test the neural specificity of motor imagery, we conducted a series of 3 experiments using transcranial magnetic stimulation (TMS). We compared changes in corticospinal excitability as people prepared and implemented actual or imagined movements, using a delayed response task in which a cue indicated the forthcoming response. TMS pulses, used to elicit motor-evoked responses in the first dorsal interosseous muscle of the right hand, were applied before and after an imperative signal, allowing us to probe the state of excitability during movement preparation and implementation. Similar to previous work, excitability increased in the agonist muscle during the implementation of an actual or imagined movement. Interestingly, preparing an imagined movement engaged similar inhibitory processes as that observed during actual movement, although the degree of inhibition was less selective in the imagery conditions. These changes in corticospinal excitability were specific to actual/imagined movement preparation, as no modulation was observed when preparing and generating images of cued visual objects. Taken together, inhibition is a signature of how actions are prepared, whether they are imagined or actually executed.

Comparative Arterial Antithrombotic Activity of Clopidogrel and Acetyl Salicylic Acid in the Pig

1992 ◽  
Vol 68 (05) ◽  
pp. 500-505 ◽  
Author(s):  
Ch M Samama ◽  
Ph Bonnin ◽  
M Bonneau ◽  
G Pignaud ◽  
E Mazoyer ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Femoral Artery ◽  
Bleeding Time ◽  
Ex Vivo ◽  
Flow Reduction ◽  
Cyclic Flow ◽  
Left Femoral Artery ◽  
Before And After ◽  
The Right ◽  
Induced Aggregation

SummaryWe investigated the comparative antithrombotic properties of clopidogrel, an analogue of ticlopidine, and aspirin, using the Folts' model on femoral arteries in 22 pigs. On each animal, clopidogrel or aspirin were used to treat the thrombotic process on the left femoral artery and to prevent this process on the right femoral artery. Sequentially: an injury and stenosis were carried out on the left femoral artery; the thrombotic process was monitored with a Doppler during a 30-min observation period for cyclic flow reductions or permanent cessation of flow; after the first cyclic flow reduction occurred, clopidogrel (5 mg kg-1) or aspirin (2.5, 5, 100 mg kg-1) were injected intravenously; if cyclic flow reductions were abolished, epinephrine (0.4 µg kg-1 min-1) was injected to try to restore cyclic flow reductions and/or permanent cessation of flow; then injury and stenosis were applied on the right femoral artery. Before and after injection of clopidogrel or aspirin, ear immersion bleeding times and ex-vivo platelet aggregation were performed. Clopidogrel (n = 7) abolished cyclic flow reductions in all animals and epinephrine did not restore any cyclic flow reduction. On the right femoral artery, cyclic flow reductions were efficiently prevented, even for two injuries. Basal bleeding time (5 min 28) was lengthened (>15 min, 30 min after clopidogrel and remained prolonged even after 24 h). ADP-induced platelet aggregation was inhibited (more than 78%). Comparatively, aspirin had a moderate and no dose-dependent effect. Aspirin 2.5 mg kg-1 (n = 6) abolished cyclic flow reductions in 2 animals, CFR reoccurred spontaneously in one animal and epinephrine restored it in a second animal. Aspirin 5 mg kg-1 (n = 6) abolished cyclic flow reductions in only 3 animals and epinephrine always restored it. Aspirin 100 mg kg-1 (n = 3) was unable to abolish cyclic flow reductions. On the right femoral artery, aspirin did not significantly prevent cyclic flow reductions which occurred in all animals after one (n = 14) or two injuries (n = 1), except for one animal. Basal bleeding time was lengthened but it shortened rapidly, reaching its basal value after 24 h. ADP-induced aggregation was not significantly inhibited, whereas arachidonic acid induced aggregation was always inhibited. Clopidogrel appears as a more potent antithrombotic drug than aspirin in this model, in treating and preventing spontaneous or epinephrine-induced cyclic flow reductions and lengthening bleeding time.

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