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Journal articles on the topic 'H-reflex'

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Published: 4 June 2021

Last updated: 25 January 2025

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1

McHugh, Daniel J., Jonathan C. Reeser, and Ernest W. Johnson. "H REFLEX AMPLITUDE." American Journal of Physical Medicine & Rehabilitation 76, no. 3 (1997): 185–87. http://dx.doi.org/10.1097/00002060-199705000-00003.

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2

Carabetta, Vito J. "H wave reflex." Archives of Physical Medicine and Rehabilitation 78, no. 12 (1997): 1394. http://dx.doi.org/10.1016/s0003-9993(97)90320-8.

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3

Thompson, Aiko K., Xiang Yang Chen, and Jonathan R. Wolpaw. "Soleus H-reflex operant conditioning changes the H-reflex recruitment curve." Muscle & Nerve 47, no. 4 (2012): 539–44. http://dx.doi.org/10.1002/mus.23620.

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4

Wolpaw, J. R. "Operant conditioning of primate spinal reflexes: the H-reflex." Journal of Neurophysiology 57, no. 2 (1987): 443–59. http://dx.doi.org/10.1152/jn.1987.57.2.443.

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The study of primate memory substrates, the CNS alterations which preserve conditioned responses, requires an experimental model that fulfills two criteria. First, the essential alterations must be in a technically accessible location. Second, they must persist without input from other CNS regions. The spinal cord is the most technically accessible and readily isolated portion of the primate CNS. Recent work has demonstrated that the spinal stretch reflex (SSR), the initial, wholly segmental response to muscle stretch, can be operantly conditioned and suggests that this conditioning may produce persistent spinal alteration. The present study attempted similar operant conditioning of the H-reflex, the electrical analog of the SSR. The primary goals were to demonstrate that spinal reflex conditioning can occur even if the muscle spindle is removed from the reflex arc and to demonstrate conditioning in the lumbosacral cord, which is far preferable to the cervical cord for future studies of neuronal and synaptic mechanisms. Nine monkeys prepared with chronic fine-wire triceps surae (gastrocnemius and soleus) electromyographic (EMG) electrodes were taught by computer to maintain a given level of background EMG activity. At random times, a voltage pulse just above M response (direct muscle response) threshold was delivered to the posterior tibial nerve via a chronically implanted silicon nerve cuff and elicited the triceps surae H-reflex. Under the control mode, reward always followed. Under the HR increases or HR decreases mode, reward followed only if the absolute value of triceps surae EMG from 12 to 22 ms after the pulse (the H-reflex interval) was above (HR increases) or below (HR decreases) a set value. Monkeys completed 3,000-6,000 trials/day over study periods of 2-3 mo. Background EMG and M response amplitude remained stable throughout data collection. H-reflex amplitude remained stable under the control mode. Under the HR increases mode (5 animals) or HR decreases mode (4 animals), H-reflex amplitude (EMG amplitude in the H-reflex interval minus background EMG amplitude) changed appropriately over at least 6 wk. Change appeared to occur in two phases: an abrupt change within the first day, followed by slower change, which continued indefinitely. Change occurred in all three triceps surae muscles (medial and lateral gastrocnemii and soleus). Under the HR increases mode, H-reflex amplitude rose to an average of 213% of control, whereas under the HR decreases mode it fell to an average of 68% of control. The results demonstrate that the H-reflex can be operantly conditioned.(ABSTRACT TRUNCATED AT 400 WORDS)

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5

Gassel, M. Michael. "Monosynaptic Reflexes (H-Reflex) and Motoneurone Excitability in Man." Developmental Medicine & Child Neurology 11, no. 2 (2008): 193–97. http://dx.doi.org/10.1111/j.1469-8749.1969.tb01417.x.

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6

Brinkworth, R. S. A., M. Tuncer, K. J. Tucker, S. Jaberzadeh, and K. S. Türker. "Standardization of H-reflex analyses." Journal of Neuroscience Methods 162, no. 1-2 (2007): 1–7. http://dx.doi.org/10.1016/j.jneumeth.2006.11.020.

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7

Misra, U. K., and C. M. Pandey. "H reflex studies in neurolathyrism." Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section 93, no. 4 (1994): 281–85. http://dx.doi.org/10.1016/0168-5597(94)90030-2.

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8

Leis, A. A., H. H. Zhou, H. L. Harkey, and W. C. Paske. "H-reflex under general anesthesia." Electroencephalography and Clinical Neurophysiology 98, no. 3 (1996): P11. http://dx.doi.org/10.1016/0013-4694(96)80265-3.

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9

Larsen, Birgit, and Michael Voigt. "Quadriceps H-Reflex Modulation During Pedaling." Journal of Neurophysiology 96, no. 1 (2006): 197–208. http://dx.doi.org/10.1152/jn.00149.2005.

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The main aims of this study were 1) to investigate possible phase-, speed-, and task-dependent changes in the quadriceps H-reflex during pedaling, and to achieve this, 2) to develop an optimized H-reflex recording and processing procedure for recording of quadriceps H-reflexes during movement. It was hypothesized that the behavior of the quadriceps H-reflex concerning phase, speed, and task dependency corresponds to the behavior of the soleus H-reflex during rhythmical leg movements. The applied H-reflex procedure appeared to be reliable for obtaining the quadriceps H-reflex modulation during leg movement. The vastus lateralis (VL) and rectus femoris (RF) H-reflexes showed a phase-dependent modulation during pedaling at a frequency of 80 rpm with almost parallel changes in the reflex amplitude and motor recruitment level. However, when the speed of movement was reduced from 80 to 40 revolutions per minute (rpm) and crank load simultaneously increased (i.e., a halving of the movement speed with a constant motor recruitment level), the quadriceps H-reflex modulation pattern changed significantly in relation to the pattern of motor recruitment, i.e., at 40 rpm, the reflex excitability remained high during a gradual derecruitment during power generation in downstroke. Comparison of the “operationally defined H-reflex gain function” obtained during 1) pedaling at 80 rpm and 2) isometric quadriceps contractions in sitting position showed no significant task-dependent changes in the quadriceps H-reflex. Consequently, the hypothesis was only partly corroborated, and the findings indicate differences in the neural control of the soleus and the quadriceps muscle during rhythmical movements.

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10

Panizza, M., S. Lelli, J. Nilsson, and M. Hallett. "H-reflex recovery curve and reciprocal inhibition of H-reflex in different kinds of dystonia." Neurology 40, no. 5 (1990): 824. http://dx.doi.org/10.1212/wnl.40.5.824.

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11

Mora-Brambila, Ana Bertha, Benjamín Trujillo-Hernández, Rafael Coll-Cardenas, et al. "Blink reflex, H-reflex and nerve-conduction alterations in leprosy patients." Leprosy Review 77, no. 2 (2006): 114–20. http://dx.doi.org/10.47276/lr.77.2.114.

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12

Robertson, Christopher T., Koichi Kitano, Masaaki Tsuruike, and David M. Koceja. "Presynaptic Inhibition of the H-reflex Relative to Test Reflex Size." Medicine & Science in Sports & Exercise 38, Supplement (2006): S441. http://dx.doi.org/10.1249/00005768-200605001-02730.

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13

Inglis, J. Greig, Anita Christie, and David A. Gabriel. "Practice Evoking the FCR H-Reflex." Medicine & Science in Sports & Exercise 36, Supplement (2004): S164. http://dx.doi.org/10.1249/00005768-200405001-00785.

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14

Macdonell, R. A., A. Talalla, M. Swash, and D. Grundy. "Intrathecal baclofen and the H-reflex." Journal of Neurology, Neurosurgery & Psychiatry 52, no. 9 (1989): 1110–12. http://dx.doi.org/10.1136/jnnp.52.9.1110.

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15

Inglis, J. Greig, Anita Christie, and David A. Gabriel. "Practice Evoking the FCR H-Reflex." Medicine & Science in Sports & Exercise 36, Supplement (2004): S164. http://dx.doi.org/10.1097/00005768-200405001-00785.

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16

Pease, W. S., R. T. Kozakiewicz, and E. W. Johnson. "CENTRAL LOOP OF THE H REFLEX." American Journal of Physical Medicine & Rehabilitation 74, no. 2 (1995): 172. http://dx.doi.org/10.1097/00002060-199503000-00022.

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17

Pease, William S., Richard Kozakiewicz, and Ernest W. Johnson. "CENTRAL LOOP OF THE H REFLEX." American Journal of Physical Medicine & Rehabilitation 76, no. 3 (1997): 182–84. http://dx.doi.org/10.1097/00002060-199705000-00002.

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18

Carp, Jonathan S., Ann M. Tennissen, Xiang Yang Chen, and Jonathan R. Wolpaw. "H-Reflex Operant Conditioning in Mice." Journal of Neurophysiology 96, no. 4 (2006): 1718–27. http://dx.doi.org/10.1152/jn.00470.2006.

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Rats, monkeys, and humans can alter the size of their spinal stretch reflex and its electrically induced analog, the H-reflex (HR), when exposed to an operant conditioning paradigm. Because this conditioning induces plasticity in the spinal cord, it offers a unique opportunity to identify the neuronal sites and mechanisms that underlie a well-defined change in a simple behavior. To facilitate these studies, we developed an HR operant conditioning protocol in mice, which are better suited to genetic manipulation and electrophysiological spinal cord study in vitro than rats or primates. Eleven mice under deep surgical anesthesia were implanted with tibial nerve stimulating electrodes and soleus and gastrocnemius intramuscular electrodes for recording ongoing and stimulus-evoked EMG activity. During the 24-h/day computer-controlled experiment, mice received a liquid reward for either increasing (up-conditioning) or decreasing (down-conditioning) HR amplitude while maintaining target levels of ongoing EMG and directly evoked EMG (M-responses). After 3–7 wk of conditioning, the HR amplitude was 133 ± 7% (SE) of control for up-conditioning and 71 ± 8% of control for down-conditioning. HR conditioning was successful (i.e., ≥20% change in HR amplitude in the appropriate direction) in five of six up-conditioned animals (mean final HR amplitude = 139 ± 5% of control HR for successful mice) and in four of five down-conditioned animals (mean final HR amplitude = 63 ± 8% of control HR for successful mice). These effects were not attributable to differences in the net level of motoneuron pool excitation, stimulation strength, or distribution of HR trials throughout the day. Thus mice exhibit HR operant conditioning comparable with that observed in rats and monkeys.

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19

Paik, Nam-Jong, and Tai Ryoon Han. "Contraction-induced H-reflex amplitude ratio." Archives of Physical Medicine and Rehabilitation 80, no. 10 (1999): 1361. http://dx.doi.org/10.1016/s0003-9993(99)90046-1.

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20

Khamis, C., and R. Jawish. "Piriformis syndrome and peroneal H-reflex." Journal of the Neurological Sciences 333 (October 2013): e426. http://dx.doi.org/10.1016/j.jns.2013.07.1532.

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21

Carp, Jonathan S., Ann M. Tennissen, Xiang Yang Chen, and Jonathan R. Wolpaw. "Diurnal H-reflex variation in mice." Experimental Brain Research 168, no. 4 (2005): 517–28. http://dx.doi.org/10.1007/s00221-005-0106-y.

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22

Hoffman, C., H. García, A. Rivero, S. Estellés, M. Merello, and M. Nogués. "H-Reflex recovery curve in syringomyelia." Electroencephalography and Clinical Neurophysiology 87, no. 2 (1993): S66—S67. http://dx.doi.org/10.1016/0013-4694(93)91147-s.

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23

Kwon, H., H. Lee, and D. Kim. "30. H reflex recorded by facilitation." Clinical Neurophysiology 119, no. 3 (2008): e36. http://dx.doi.org/10.1016/j.clinph.2007.11.080.

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24

Matek, P., J. Geber, and Ana Bobinac-Georgievski. "Benzodiazepam effects on the H-reflex." Electroencephalography and Clinical Neurophysiology 61, no. 3 (1985): S207—S208. http://dx.doi.org/10.1016/0013-4694(85)90790-4.

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25

Xiang Yang Chen and Jonathan R. Wolpaw. "Circadian rhythm in rat H-reflex." Brain Research 648, no. 1 (1994): 167–70. http://dx.doi.org/10.1016/0006-8993(94)91918-6.

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26

Koelman, J. H. T. M., R. B. Willemse, L. J. Bour, A. A. J. Hilgevoord, J. D. Speelman, and B. W. Ongerboer de Visse. "Soleus H-reflex tests in dystonia." Movement Disorders 10, no. 1 (1995): 44–50. http://dx.doi.org/10.1002/mds.870100109.

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27

Funase, K., K. Imanaka, and Y. Nishihira. "Inhibition of the Soleus H-Reflex during Dorsiflexion is Dependent on Individual Differences in Maximal Soleus H-Reflex as a Test Reflex." Perceptual and Motor Skills 82, no. 2 (1996): 403–10. http://dx.doi.org/10.2466/pms.1996.82.2.403.

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The quantitative differences among individuals in the natural reciprocal inhibition of the soleus H-reflex during dorsiflexion were examined, in conjunction with the maximal H-reflex as the test reflex size in each individual. Maximal H-reflex was expressed relative to the maximal M-response (Hmax) when compared among individuals. Analysis showed that with increases in Hmax at rest in each individual, the inhibitory effect was first enhanced, then reached a peak, and was finally alleviated. This pattern was similar to the intraindividual pattern of the inhibitory effect induced by specific conditioning stimulus as a function of the test reflex size.

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28

Chen, Y., L. Chen, Y. Wang, J. R. Wolpaw, and X. Y. Chen. "Operant Conditioning of Rat Soleus H-Reflex Oppositely Affects Another H-Reflex and Changes Locomotor Kinematics." Journal of Neuroscience 31, no. 31 (2011): 11370–75. http://dx.doi.org/10.1523/jneurosci.1526-11.2011.

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29

Tseng, K. C., and Helen Sheau-Ping Pan. "Evaluation of Suppression Periods on Monosynaptic Reflex (H-Reflex) in Young Adults." Rehabilitation Practice and Science 21, no. 1 (1993): 21–25. http://dx.doi.org/10.6315/3005-3846.1876.

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30

Mrachacz-Kersting, N., U. G. Kersting, P. de Brito Silva, et al. "Acquisition of a simple motor skill: task-dependent adaptation and long-term changes in the human soleus stretch reflex." Journal of Neurophysiology 122, no. 1 (2019): 435–46. http://dx.doi.org/10.1152/jn.00211.2019.

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Changing the H reflex through operant conditioning leads to CNS multisite plasticity and can affect previously learned skills. To further understand the mechanisms of this plasticity, we operantly conditioned the initial component (M1) of the soleus stretch reflex. Unlike the H reflex, the stretch reflex is affected by fusimotor control, comprises several bursts of activity resulting from temporally dispersed afferent inputs, and may activate spinal motoneurons via several different spinal and supraspinal pathways. Neurologically normal participants completed 6 baseline sessions and 24 operant conditioning sessions in which they were encouraged to increase (M1up) or decrease (M1down) M1 size. Five of eight M1up participants significantly increased M1; the final M1 size of those five participants was 143 ± 15% (mean ± SE) of the baseline value. All eight M1down participants significantly decreased M1; their final M1 size was 62 ± 6% of baseline. Similar to the previous H-reflex conditioning studies, conditioned reflex change consisted of within-session task-dependent adaptation and across-session long-term change. Task-dependent adaptation was evident in conditioning session 1 with M1up and by session 4 with M1down. Long-term change was evident by session 10 with M1up and by session 16 with M1down. Task-dependent adaptation was greater with M1up than with the previous H-reflex upconditioning. This may reflect adaptive changes in muscle spindle sensitivity, which affects the stretch reflex but not the H reflex. Because the stretch reflex is related to motor function more directly than the H reflex, M1 conditioning may provide a valuable tool for exploring the functional impact of reflex conditioning and its potential therapeutic applications. NEW & NOTEWORTHY Since the activity of stretch reflex pathways contributes to locomotion, changing it through training may improve locomotor rehabilitation in people with CNS disorders. Here we show for the first time that people can change the size of the soleus spinal stretch reflex through operant conditioning. Conditioned stretch reflex change is the sum of task-dependent adaptation and long-term change, consistent with H-reflex conditioning yet different from it in the composition and amount of the two components.

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31

Alrowayeh, Hesham N., and Mohamed A. Sabbahi. "Vastus Medialis H-Reflex Reliability During Standing." Journal of Clinical Neurophysiology 23, no. 1 (2006): 79–84. http://dx.doi.org/10.1097/01.wnp.0000193632.75002.d3.

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32

Beekley, M. D., C. A. Long, and W. F. Brechue. "HYPERCAPNIA DEPRESSES THE H REFLEX IN HUMANS." Medicine & Science in Sports & Exercise 31, Supplement (1999): S206. http://dx.doi.org/10.1097/00005768-199905001-00950.

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33

Johnson, Ernest W. "Understanding the "H" Reflex in Lumbosacral Radiculopathy." American Journal of Physical Medicine & Rehabilitation 78, no. 5 (1999): 407. http://dx.doi.org/10.1097/00002060-199909000-00001.

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34

Grosprêtre, Sidney, and Alain Martin. "H reflex and spinal excitability: methodological considerations." Journal of Neurophysiology 107, no. 6 (2012): 1649–54. http://dx.doi.org/10.1152/jn.00611.2011.

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The Hoffmann reflex has been the tool most commonly used in exercise studies to investigate modulations in spinal excitability. However, the evolution of electromyographic responses with the increase in stimulation intensity has rarely been assessed when the muscle is active. The purpose of this study was thus to identify that part of the recruitment curve at which the investigation of the Hoffmann reflex is the most reliable in assessing spinal excitability during muscle contraction. Two recruitment curves were determined from the soleus and the medialis gastrocnemius, in passive and active (50% of maximal isometric voluntary contraction) conditions. No differences were found between the H reflexes in the two conditions in the ascending part of the recruitment curves, while the intensity necessary to elicit the same percentage of maximal H wave was different in the descending part of the curve, up to the maximal M wave. We concluded that during motor tasks, changes in spinal excitability should be assessed by recording H responses in the ascending part of the curve, where modulations do not depend either on the background electrical activity of the muscle tested or on methodological considerations.

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35

Tsuruike, Masaaki, Koichi Kitano, and David M. Koceja. "H-reflex Modulation During Different Head Movements." Medicine & Science in Sports & Exercise 41 (May 2009): 355. http://dx.doi.org/10.1249/01.mss.0000355630.39973.9f.

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36

Brooke, J. D., S. P. Dukelow, K. B. Adamo, J. Cheng, W. R. Staines, and J. E. Misiaszek. "H-reflex modulation during reverse passive pedalling." Journal of Electromyography and Kinesiology 6, no. 2 (1996): 111–16. http://dx.doi.org/10.1016/1050-6411(95)00027-5.

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37

Panizza, M., J. Nilsson, and M. Hallett. "Optimal stimulus duration for the H reflex." Muscle & Nerve 12, no. 7 (1989): 576–79. http://dx.doi.org/10.1002/mus.880120708.

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38

Falco, Frank J. E., William J. Hennessey, Gary Goldberg, and Randall L. Braddom. "H reflex latency in the healthy elderly." Muscle & Nerve 17, no. 2 (1994): 161–67. http://dx.doi.org/10.1002/mus.880170205.

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39

Andersen, Jacob Buus, and Thomas Sinkjaer. "The Stretch Reflex and H-Reflex of the Human Suleus Muscle during Walking." Motor Control 3, no. 2 (1999): 151–57. http://dx.doi.org/10.1123/mcj.3.2.151.

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40

Kamibayashi, Kiyotaka, Kimitaka Nakazawa, Hisayoshi Ogata, Hiroki Obata, Masami Akai, and Minoru Shinohara. "Invariable H-reflex and sustained facilitation of stretch reflex with heightened sympathetic outflow." Journal of Electromyography and Kinesiology 19, no. 6 (2009): 1053–60. http://dx.doi.org/10.1016/j.jelekin.2008.11.002.

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41

Kozhina, G. V., and R. S. Person. "State of monosynaptic reflex (H reflex) arc during voluntary muscle contraction in humans." Neurophysiology 25, no. 5 (1994): 303–7. http://dx.doi.org/10.1007/bf01054262.

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42

Makihara, Yukiko, Richard L. Segal, Jonathan R. Wolpaw, and Aiko K. Thompson. "Operant conditioning of the soleus H-reflex does not induce long-term changes in the gastrocnemius H-reflexes and does not disturb normal locomotion in humans." Journal of Neurophysiology 112, no. 6 (2014): 1439–46. http://dx.doi.org/10.1152/jn.00225.2014.

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In normal animals, operant conditioning of the spinal stretch reflex or the H-reflex has lesser effects on synergist muscle reflexes. In rats and people with incomplete spinal cord injury (SCI), soleus H-reflex operant conditioning can improve locomotion. We studied in normal humans the impact of soleus H-reflex down-conditioning on medial (MG) and lateral gastrocnemius (LG) H-reflexes and on locomotion. Subjects completed 6 baseline and 30 conditioning sessions. During conditioning trials, the subject was encouraged to decrease soleus H-reflex size with the aid of visual feedback. Every sixth session, MG and LG H-reflexes were measured. Locomotion was assessed before and after conditioning. In successfully conditioned subjects, the soleus H-reflex decreased 27.2%. This was the sum of within-session (task dependent) adaptation (13.2%) and across-session (long term) change (14%). The MG H-reflex decreased 14.5%, due mainly to task-dependent adaptation (13.4%). The LG H-reflex showed no task-dependent adaptation or long-term change. No consistent changes were detected across subjects in locomotor H-reflexes, EMG activity, joint angles, or step symmetry. Thus, in normal humans, soleus H-reflex down-conditioning does not induce long-term changes in MG/LG H-reflexes and does not change locomotion. In these subjects, task-dependent adaptation of the soleus H-reflex is greater than it is in people with SCI, whereas long-term change is less. This difference from results in people with SCI is consistent with the fact that long-term change is beneficial in people with SCI, since it improves locomotion. In contrast, in normal subjects, long-term change is not beneficial and may necessitate compensatory plasticity to preserve satisfactory locomotion.

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43

Scalia, Martina, Riccardo Borzuola, Martina Parrella, et al. "Neuromuscular Electrical Stimulation Does Not Influence Spinal Excitability in Multiple Sclerosis Patients." Journal of Clinical Medicine 13, no. 3 (2024): 704. http://dx.doi.org/10.3390/jcm13030704.

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(1) Background: Neuromuscular electrical stimulation (NMES) has beneficial effects on physical functions in Multiple sclerosis (MS) patients. However, the neurophysiological mechanisms underlying these functional improvements are still unclear. This study aims at comparing acute responses in spinal excitability, as measured by soleus Hoffmann reflex (H-reflex), between MS patients and healthy individuals, under three experimental conditions involving the ankle planta flexor muscles: (1) passive NMES (pNMES); (2) NMES superimposed onto isometric voluntary contraction (NMES+); and (3) isometric voluntary contraction (ISO). (2) Methods: In total, 20 MS patients (MS) and 20 healthy individuals as the control group (CG) took part in a single experimental session. Under each condition, participants performed 15 repetitions of 6 s at 20% of maximal voluntary isometric contraction, with 6 s of recovery between repetitions. Before and after each condition, H-reflex amplitudes were recorded. (3) Results: In MS, H-reflex amplitude did not change under any experimental condition (ISO: p = 0.506; pNMES: p = 0.068; NMES+: p = 0.126). In CG, H-reflex amplitude significantly increased under NMES+ (p = 0.01), decreased under pNMES (p < 0.000) and was unaltered under ISO (p = 0.829). (4) Conclusions: The different H-reflex responses between MS and CG might reflect a reduced ability of MS patients in modulating spinal excitability.

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44

Baars, Jan H., René Mager, Katharina Dankert, Mark Hackbarth, Falk von Dincklage, and Benno Rehberg. "Effects of Sevoflurane and Propofol on the Nociceptive Withdrawal Reflex and on the H Reflex." Anesthesiology 111, no. 1 (2009): 72–81. http://dx.doi.org/10.1097/aln.0b013e3181a4c706.

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Background The predominant target of anesthetics to suppress movement responses to noxious stimuli is located in the spinal cord. Although volatile anesthetics appear to produce immobility by actions on the ventral rather than the dorsal horn, the site of action of propofol remains unclear. Methods In a crossover design, the authors compared in 13 volunteers the effects of sevoflurane and propofol on the amplitudes of the H reflex, which is mediated exclusively in the ventral horn and a withdrawal reflex (RIII Reflex), which integrates dorsal and ventral horn function. The concentrations were adjusted according to a Dixon up-and-down approach, depending on movement responses to tetanic stimulation. Results Sevoflurane and propofol concentrations ranged from 1.2 to 1.6 Vol% and 3 to 6 mg/l, respectively. Sevoflurane reduced the H reflex amplitude significantly to 66 +/- 17% (mean +/- SD) of its control values. Propofol did not significantly reduce the H reflex. The reductions under the two drugs differed significantly. The RIII reflex amplitude was significantly reduced to 19 +/- 10% and 27 +/- 12% (mean +/- SD) of the control values by sevoflurane and propofol, respectively. The reductions did not differ between the drugs. Conclusions Probably because of the polysynaptic relay, the attenuation of the withdrawal reflex exceeds the attenuation of the H reflex. Sevoflurane produces a larger inhibitory effect on the H reflex than propofol, which confirms that the ventral horn is a more important target for volatile anesthetics, whereas effects of propofol on this site of action are rather limited. Our findings indirectly suggest for propofol a relatively stronger effect within the dorsal horn.

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45

Yang, J. F., J. Fung, M. Edamura, R. Blunt, R. B. Stein, and H. Barbeau. "H-Reflex Modulation During Walking in Spastic Paretic Subjects." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 18, no. 4 (1991): 443–52. http://dx.doi.org/10.1017/s0317167100032133.

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ABSTRACT:Hoffmann (H) reflexes were elicited from the soleus muscle during treadmill walking in 21 spastic paretic patients. The soleus and tibialis anterior muscles were reciprocally activated during walking in most patients, much like that observed in healthy individuals. The pattern of H-reflex modulation varied considerably between patients, from being relatively normal in some patients to a complete absence of modulation in others. The most common pattern observed was a lack of H-reflex modulation through the stance phase and slight depression of the reflex in the swing phase, considerably less modulation than that of normal subjects under comparable walking conditions. The high reflex amplitudes during periods of the step cycle such as early stance seems to be related to the stretch-induced large electromyogram bursts in the soleus in some subjects. The abnormally active reflexes appear to contribute to the clonus encountered during walking in these patients. In three patients who were able to walk for extended periods, the effect of stimulus intensity was examined. Two of these patients showed a greater degree of reflex modulation at lower stimulus intensities, suggesting that the lack of modulation observed at higher stimulus intensities is a result of saturation of the reflex loop. In six other patients, however, no reflex modulation could be demonstrated even at very low stimulus intensities.

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Kerz, Thomas, Hans-Jürgen Hennes, Annaïk Fève, Philippe Decq, Paul Filipetti, and Philippe Duvaldestin. "Effects of Propofol on H-reflex in Humans." Anesthesiology 94, no. 1 (2001): 32–37. http://dx.doi.org/10.1097/00000542-200101000-00010.

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Background Depression of spinal cord motoneuron excitability has been proposed to contribute to surgical immobility. The H-reflex, which measures alpha-motoneuron excitability, is depressed by volatile anesthetics, whereas the action of propofol is unknown. The objective of this study was to determine the effects of propofol anesthesia on the H-reflex. Methods In 13 patients (group 1), H-reflex was measured before (T0), 3 min after (T1), and 10 min after (T2) a 2-mg/kg bolus dose of propofol, followed by an infusion of 10 mg x kg(-1) x h(-1). Ten patients (group 2) were studied when propofol was given via a programmable pump set to a propofol blood concentration of 6 microg/ml, and 10 patients (group 3) were studied with the pump set to 9 microg/ml. Latencies and amplitudes of H-reflexes (H0, H1, H2) and M-responses (M0, M1, M2) of the soleus muscle were recorded, and H/M ratios (H0/M0, H1/M1, H2/M2) were calculated. Results In group 1, H-reflex amplitudes and the H/M ratio were diminished after induction with propofol (H0 vs. H1, P = 0.033; H0/M0 vs. H1/M1, P = 0.042). After 10 min of propofol infusion, the H2/M2 ratio was still decreased versus H0/M0 (P = 0.031). In group 2, no difference was detected. In group 3, propofol depressed H-reflex amplitudes at T2 (H0 vs. H2, P &lt; 0.01), and amplitudes were also lower at T2 than at T1 (H1 vs. H2, P &lt; 0.01). In this group, the H/M ratio decreased from T0 to T2 (H0/M0 vs. H2/M2, P &lt; 0.002). Conclusions During steady state conditions using propofol as the sole agent, a depression of the H-reflex is observed only at a high blood concentration of 9 microg/ml. The authors suggest that immobility during propofol anesthesia is not caused by a depression of spinal motoneuron circuit excitability.

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Šádek, P., E. Hrušková, S. Ostrý, and J. Otáhal. "Neurophysiological Assessment of H-Reflex Alterations in Compressive Radiculopathy." Physiological Research, no. 3/2024 (July 10, 2024): 427–33. http://dx.doi.org/10.33549/physiolres.935325.

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This study aimed to investigate changes in the H-reflex recruitment curve in compressive radiculopathy, specifically assessing differences between symptomatic and asymptomatic limbs in patients with unilateral S1 radiculopathy through derived parameters. A total of 24 volunteers (15 male and 9 female, aged between 22 and 60 years) with confirmed nerve root compression in the L5/S1 segment participated. Nerve root compression was verified through clinical MRI examination and attributed to disc protrusion, spinal canal stenosis, or isthmic spondylolisthesis of L5/S1. Analysis revealed no difference in M-wave threshold intensity between symptomatic and non-symptomatic limbs. However, the H-reflex exhibited a trend toward increased threshold intensity in the symptomatic limb. Notably, a significant decrease in the slope of the H-reflex was observed on the symptomatic side, and the maximal H-reflex amplitude proved to be markedly different between the two limbs. The Hmax/Mmax ratio demonstrated a significant decrease in the symptomatic limb, indicating reduced effectiveness of signal translation. In conclusion, our findings emphasize the importance of H-reflex parameters in evaluating altered recruitment curves, offering valuable insights for neurological examinations. The observed differences in maximal values of M-wave, H-reflex, and their ratio in affected and unaffected limbs can enhance the diagnostic process for lumbosacral unilateral radiculopathy and contribute to a standardized approach in clinical assessments.

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Chen, X. Y., and J. R. Wolpaw. "Operant conditioning of H-reflex in freely moving rats." Journal of Neurophysiology 73, no. 1 (1995): 411–15. http://dx.doi.org/10.1152/jn.1995.73.1.411.

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1. Primates can increase or decrease the spinal stretch reflex and its electrical analogue, the H-reflex (HR), in response to an operant conditioning task. This conditioning changes the spinal cord itself and thereby provides an experimental model for defining the processes and substrates of a learned change in behavior. Because the phenomenon has been demonstrated only in primates, its generality and theoretical implications remain unclear, and its experimental use is restricted by the difficulties of primate research. In response to these issues, the present study explored operant conditioning of the H-reflex in the rat. 2. Seventeen Sprague-Dawley rats implanted with chronic electromyographic (EMG) recording electrodes in one soleus muscle and nerve cuff stimulating electrodes on the posterior tibial nerve were rewarded (either with medial forebrain bundle stimulation or food) for increasing (HRup conditioning mode) or decreasing (HRdown conditioning mode) soleus H-reflex amplitude without change in background EMG or M response (direct muscle response) amplitude. 3. H-reflex amplitude changed appropriately over 3-4 wk. Under the HRup mode, it rose to an average of 158 +/- 54% (mean +/- SD) of initial value, whereas under the HRdown mode it fell to an average of 67 +/- 11% of initial value. Background EMG and M response amplitude did not change. 4. Operant conditioning of the H-reflex in the rat appears similar in rate and final magnitude of change to that observed in the monkey.(ABSTRACT TRUNCATED AT 250 WORDS)

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McNulty, Penelope A., Stacey K. Jankelowitz, Tanya M. Wiendels, and David Burke. "Postactivation Depression of the Soleus H Reflex Measured Using Threshold Tracking." Journal of Neurophysiology 100, no. 6 (2008): 3275–84. http://dx.doi.org/10.1152/jn.90435.2008.

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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.

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Miyahara, Takao. "Modulation of Soleus H-Reflex by Teeth Clenching." JOURNAL OF THE STOMATOLOGICAL SOCIETY,JAPAN 58, no. 4 (1991): 670–86. http://dx.doi.org/10.5357/koubyou.58.670.

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