Spinal motoneuronal excitability in hyperkinesis: H-reflex recovery function and homosynaptic depression during wakefulness

1981 ◽  
Vol 3 (3) ◽  
pp. 215-236 ◽  
Author(s):  
R. T. Pivik ◽  
L. Mercier
Keyword(s):  
H Reflex ◽  
Recovery Function ◽  
Homosynaptic Depression

Effects of homosynaptic depression on spectral properties of H-reflex recordings

2012 ◽  
Vol 29 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Kristof Kipp ◽  
Samuel T. Johnson ◽  
Mark A. Hoffman
Keyword(s):  
Spectral Properties ◽  
H Reflex ◽  
Homosynaptic Depression

Postactivation Depression of the Soleus H Reflex Measured Using Threshold Tracking

2008 ◽  
Vol 100 (6) ◽  
pp. 3275-3284 ◽  
Author(s):  
Penelope A. McNulty ◽  
Stacey K. Jankelowitz ◽  
Tanya M. Wiendels ◽  
David Burke
Keyword(s):  
Plantar Flexion ◽  
H Reflex ◽  
Homosynaptic Depression ◽  
Threshold Tracking ◽  
Nonlinear Input ◽  
The Face ◽  
Reflex Gain ◽  
Afferent Inputs ◽  
Voluntary Contractions ◽  
Postactivation Depression

The interpretation of changes in the soleus H reflex is problematic in the face of reflex gain changes, a nonlinear input/output relationship for the motoneuron pool, and a nonhomogeneous response of different motoneurons to afferent inputs. By altering the stimulus intensity to maintain a constant reflex output, threshold tracking allows a relatively constant population of α-motoneurons to be studied. This approach was used to examine postactivation (“homosynaptic”) depression of the H reflex (HD) in 23 neurologically healthy subjects. The H reflex was elicited by tibial nerve stimulation at 0.05, 0.1, 0.3, 1, and 2 Hz at rest and during voluntary plantar flexion at 2.5, 5, and 10% of maximum. A computerized threshold tracking procedure was used to set the current needed to generate a target H reflex 10% of Mmax. The current needed to produce the target reflex increased with stimulus rate but not significantly beyond 1 Hz. In three subjects, the current needed to produce H reflexes of 5, 10, 15, and 20% Mmax at 0.3, 1, and 2 Hz increased with rate and with the size of the test H reflex. HD was significantly reduced during voluntary contractions. Using threshold tracking, HD was maximal at lower frequencies than previously emphasized, probably because HD is greater the larger the test H reflex. This would reinforce the greater sensitivity of small motoneurons to reflex inputs.

Effect of chlorpromazine on H-reflex recovery curves in normal subjects and schizophrenic patients

1982 ◽  
Vol 78 (4) ◽  
pp. 342-345 ◽  
Author(s):  
John Metz ◽  
Henry H. Holcomb ◽  
Herbert Y. Meltzer
Keyword(s):  
Normal Subjects ◽  
H Reflex ◽  
Recovery Curves ◽  
Schizophrenic Patients

scholarly journals Specific modulation of corticomuscular coherence during submaximal voluntary isometric, shortening and lengthening contractions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dorian Glories ◽  
Mathias Soulhol ◽  
David Amarantini ◽  
Julien Duclay
Keyword(s):  
H Reflex ◽  
Medial Gastrocnemius ◽  
Emg Activity ◽  
Beta Band ◽  
Lengthening Contractions ◽  
Time Frequency ◽  
Corticomuscular Coherence ◽  
Emg Signal ◽  
Voluntary Contractions ◽  
Spinal Excitability

AbstractDuring voluntary contractions, corticomuscular coherence (CMC) is thought to reflect a mutual interaction between cortical and muscle oscillatory activities, respectively measured by electroencephalography (EEG) and electromyography (EMG). However, it remains unclear whether CMC modulation would depend on the contribution of neural mechanisms acting at the spinal level. To this purpose, modulations of CMC were compared during submaximal isometric, shortening and lengthening contractions of the soleus (SOL) and the medial gastrocnemius (MG) with a concurrent analysis of changes in spinal excitability that may be reduced during lengthening contractions. Submaximal contractions intensity was set at 50% of the maximal SOL EMG activity. CMC was computed in the time–frequency domain between the Cz EEG electrode signal and the unrectified SOL or MG EMG signal. Spinal excitability was quantified through normalized Hoffmann (H) reflex amplitude. The results indicate that beta-band CMC and normalized H-reflex were significantly lower in SOL during lengthening compared with isometric contractions, but were similar in MG for all three muscle contraction types. Collectively, these results highlight an effect of contraction type on beta-band CMC, although it may differ between agonist synergist muscles. These novel findings also provide new evidence that beta-band CMC modulation may involve spinal regulatory mechanisms.

scholarly journals Acute Effects of Kinesiology Taping Stretch Tensions on Soleus and Gastrocnemius H-Reflex Modulations

2021 ◽  
Vol 18 (9) ◽  
pp. 4411
Author(s):  
Yung-Sheng Chen ◽  
Shi Zhou ◽  
Zachary J. Crowley-McHattan ◽  
Pedro Bezerra ◽  
Wei-Chin Tseng ◽  
...  
Keyword(s):  
H Reflex ◽  
Triceps Surae ◽  
Reflex Modulation ◽  
Hoffmann Reflex ◽  
Acute Effects ◽  
Physically Active ◽  
M Wave ◽  
Subject Design ◽  
Minor Influence ◽  
Order Paper

This study examined the acute effects of stretch tensions of kinesiology taping (KT) on the soleus (SOL), medial (MG), and lateral (LG) gastrocnemius Hoffmann-reflex (H-reflex) modulation in physically active healthy adults. A cross-over within-subject design was used in this study. Twelve physically active collegiate students voluntarily participated in the study (age = 21.3 ± 1.2 years; height = 175.6 ± 7.1 cm; body weight = 69.9 ± 7.1 kg). A standard Y-shape of KT technique was applied to the calf muscles. The KT was controlled in three tension intensities in a randomised order: paper-off, 50%, and 100% of maximal stretch tension of the tape. The peak-to-peak amplitude of maximal M-wave (Mmax) and H-reflex (Hmax) responses in the SOL, MG, and LG muscles were assessed before taping (pre-taping), taping, and after taping (post-taping) phases in the lying prone position. The results demonstrated significantly larger LG Hmax responses in the pre-taping condition than those in the post-taping condition during paper-off KT (p = 0.002). Moreover, the ΔHmax/Mmax of pre- and post-taping in the SOL muscle was significantly larger during 50%KT tension than that of paper-off (p = 0.046). In conclusion, the stretch tension of KT contributes minor influence on the spinal motoneuron excitability in the triceps surae during rest.

Sign in / Sign up

Export Citation Format

Share Document