scholarly journals Sensory enhancement amplifies interlimb cutaneous reflexes in wrist extensor muscles

2019 ◽  
Vol 122 (5) ◽  
pp. 2085-2094 ◽  
Author(s):  
Yao Sun ◽  
E. Paul Zehr
Keyword(s):  
Motor Function ◽  
Sensory Input ◽  
The Body ◽  
Cutaneous Reflexes ◽  
Motor Tasks ◽  
Wrist Extensor ◽  
Cutaneous Reflex ◽  
Extensor Muscles ◽  
Wrist Extensor Muscles ◽  
Sensory Enhancement

Interlimb neural connections support motor tasks such as locomotion and cross-education strength training. Somatosensory pathways that can be assessed with cutaneous reflex paradigms assist in subserving these connections. Many studies show that stimulation of cutaneous nerves elicits reflexes in muscles widespread across the body and induces neural plasticity after training. Sensory enhancement, such as long-duration trains of transcutaneous stimulation, facilitates performance during rehabilitation training or fatiguing motor tasks. Performance improvements due to sensory stimulation may be caused by altered spinal and corticospinal excitability. However, how enhanced sensory input regulates the excitability of interlimb cutaneous reflex pathways has not been studied. Our purpose was to investigate the effects of sensory enhancement on interlimb cutaneous reflexes in wrist extensor muscles. Stimulation to provide sensory enhancement (2-s trains at 150 Hz to median or superficial radial nerves) or evoke cutaneous reflexes (15-ms trains at 300 Hz to superficial radial nerve) was applied in different arms while participants ( n = 13) performed graded isometric wrist extension. Wrist extensor electromyography and cutaneous reflexes were measured bilaterally. We found amplified inhibitory reflexes in the arm receiving superficial radial and median nerve sensory enhancement with net reflex amplitudes decreased by 709.5% and 695.3% repetitively. This suggests sensory input alters neuronal excitabilities in the interlimb cutaneous pathways. These findings have potential application in facilitating motor function recovery through alterations in spinal cord excitability enhancing sensory input during targeted rehabilitation and sports training. NEW & NOTEWORTHY We show that sensory enhancement increases excitability in interlimb cutaneous pathways and that these effects are not influenced by descending motor drive on the contralateral side. These findings confirm the role of sensory input and cutaneous pathways in regulating interlimb movements. In targeted motor function training or rehabilitation, sensory enhancement may be applied to facilitate outcomes.

Ipsilateral and contralateral effects on cutaneous reflexes in a back muscle of the female rat: modulation by steroids relevant for reproductive behavior

1990 ◽  
Vol 64 (3) ◽  
pp. 835-846 ◽  
Author(s):  
S. Schwartz-Giblin ◽  
D. W. Pfaff
Keyword(s):  
Nerve Stimulation ◽  
The Body ◽  
Female Rats ◽  
Female Rat ◽  
Cutaneous Reflexes ◽  
Intravenous Injections ◽  
Cutaneous Reflex ◽  
Early Peak ◽  
Number Of Discharges ◽  
Back Extensor

1. Multiunit EMG recordings of cutaneous reflexes--evoked in the back extensor, lateral longissimus (LL), by bilateral stimulation of nerves to dorsal flank skin--were studied in ovariectomized female rats with and without estrogen pretreatment. 2. Poststimulus time (PST) histograms of data from rats with and without estrogen pretreatment show that the axial EMG response (10-30 ms) to ipsilateral (ipsi) flank skin nerve stimulation is significantly shorter in latency (1.4 ms) and 67% larger than the response to contralateral (contra) flank skin nerve stimulation recorded at the same site (n = 29 pairs). 3. When late EMG responses were also evoked at 50-120 ms in 37% of ipsi and 29% of contra cutaneous reflexes, the incidence of multiunit activity in the late peak was significantly greater in rats pretreated with silastics containing 100% estradiol (E) compared with 10% E or cholesterol controls. 4. When an ipsi cutaneous reflex in LL was conditioned by a stimulus to the contra flank skin nerve at a condition-test interval of 30 ms (C-T 30 ms), the average number of discharges in the early peak of the histogram was double that in the histogram obtained from the unconditioned ipsi reflex, independent of estrogen pretreatment. 5. In 12 out of 19 cases in which a contra cutaneous reflex was conditioned by a stimulus to the ipsi flank skin nerve (C-T 30 ms), the number of discharges in the early peak of the histogram was less than that in the early peak of the histogram derived from the unconditioned contra response, independent of estrogen pretreatment. 6. Intravenous injections of progesterone (P) or its metabolite 5 alpha-pregnane-3 alpha-ol-20-one (tetrahydraprogesterone, THP) decreased the magnitude of the early peak of the ipsi cutaneous reflex and the contra cutaneous reflex in LL, independent of estrogen pretreatment. At the same time, it did not reduce the magnitude of the early peak evoked by either ipsi or contra nerves after conditioning from the other side at C-T 30 ms. 7. As a consequence, the percentage facilitation of ipsi cutaneous reflexes by contra cutaneous conditioning was significantly increased after P or THP. This suggests that these steroids can selectively enhance behaviors involving bilateral inputs. 8. An unchanged axial motoneuron pool output to bilateral cutaneous inputs after P and THP, in spite of reduced motoneuron responses to cutaneous inputs from each side of the body, implies an increased gain in the reflex circuit.(ABSTRACT TRUNCATED AT 400 WORDS)

EXTERNAL EXTENSION FORCE REDUCES ELECTROMYOGRAPHIC ACTIVITY OF THE WRIST EXTENSOR MUSCLES DURING GRIPPING

2003 ◽  
Vol 35 (Supplement 1) ◽  
pp. S318
Author(s):  
N van Elk ◽  
J G.M. Kooloos ◽  
M Massa ◽  
J A. de Lint ◽  
M T.E. Hopman
Keyword(s):  
Electromyographic Activity ◽  
Wrist Extensor ◽  
Extensor Muscles ◽  
Wrist Extensor Muscles ◽  
Extension Force

Activity patterns of wrist extensor muscles during wrist extensions and deviations

2004 ◽  
Vol 31 (2) ◽  
pp. 242-251 ◽  
Author(s):  
L. Finsen ◽  
K. Søgaard ◽  
T. Graven-Nielsen ◽  
H. Christensen
Keyword(s):  
Activity Patterns ◽  
Wrist Extensor ◽  
Extensor Muscles ◽  
Wrist Extensor Muscles

scholarly journals Comparison of the electrical activity in upper trapezius and wrist extensor muscles during two typewriting conditions

2014 ◽  
Vol 27 (2) ◽  
pp. 271-279 ◽  
Author(s):  
João Carlos Comel ◽  
João Pedro Batista Junior ◽  
Eliana Paula Chini ◽  
Hugo Maxwell Pereira ◽  
Rodrigo Luiz Carregaro ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Repeated Measures ◽  
Perceived Exertion ◽  
Electromyographic Activity ◽  
Wrist Extensor ◽  
Upper Trapezius ◽  
Extensor Muscles ◽  
Significant Difference ◽  
Arm Support ◽  
Wrist Extensor Muscles

Introduction The proper use of the position of the arm and wrist while typing may reduce muscle overload and prevent musculoskeletal disorders.Objective To evaluate the electromyographic activity of upper trapezius and wrist extensor muscles during two typewriting conditions.Materials and methods : Six healthy females (Xage = 42 years,SD= 10), (Xheight = 1.65m, SD = 0.05) and (Xweight = 71kg, SD = 16) participated in this study. The task was performed with a newly developed arm support and without the support. A perceived exertion scale was used with all subjects. An ANOVA with repeated measures was used to verify differences in perceived exertion and root mean square (RMS).Results There were no statistically significant differences for the RMS between the typewriting tasks. The condition without arm support presented a significantly greater mean velocity and amount of words typed (P= 0.02; P= 0.03) and there was a significant difference in perceived exertion during the condition without arm support (P= 0.03). Electromyographic activity did not present differences.Conclusion The muscle electrical activity was not altered regardless the arm support and occurred the improvement of the perceived exertion after 10 minutes of typing without support. Long-term studies are needed.

scholarly journals Carry-over effect in integrated volitional control electrical stimulation of wrist extensor muscles for stroke patients

Nosotchu ◽  
2013 ◽  
Vol 35 (3) ◽  
pp. 174-180
Author(s):  
Chieko Usami ◽  
Hiroyuki Miyasaka ◽  
Hitomi Uematsu ◽  
Izumi Kondo ◽  
Yutaka Tomita ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Stroke Patients ◽  
Volitional Control ◽  
Wrist Extensor ◽  
Extensor Muscles ◽  
Wrist Extensor Muscles ◽  
Carry Over ◽  
Stimulation Of ◽  
Carry Over Effect
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