The Experts below are selected from a list of 117 Experts worldwide ranked by ideXlab platform

Steven R Passmore - One of the best experts on this subject based on the ideXlab platform.

  • anatomically remote muscle contraction facilitates patellar tendon reflex reinforcement while mental activity does not a within participants experimental trial
    Chiropractic & Manual Therapies, 2012
    Co-Authors: Steven R Passmore, Paul Bruno
    Abstract:

    The Jendrassik Maneuver (JM) is a remote facilitation muscular contraction shown to affect amplitude and temporal components of the human stretch reflex. Conflicting theoretical models exist regarding the neurological mechanism related to its ability to reinforce reflex parameters. One mechanism involves the gamma motoneurons of the fusimotor system, which are subject to both physical and mental activity. A second mechanism describes reduced alpha motoneuron presynaptic inhibition, which is not subject to mental activity. In the current study, we determined if mental activity could be used to create a reflex facilitation comparable to a remote muscle contraction. Using a within-participants design, we investigated the relative effect of the JM and a successfully employed mental task (Stroop task) on the amplitude and temporal components of the patellar tendon reflex. We found that the addition of mental activity had no influence on the patellar tendon reflex parameters measured, while the JM provided facilitation (increased reflex amplitude, decreased total reflex time). The findings from this study support the view that the mechanism for the JM is a reduction in presynaptic inhibition of alpha motoneurons as it is influenced by physical and not mental activity.

Paul Bruno - One of the best experts on this subject based on the ideXlab platform.

  • anatomically remote muscle contraction facilitates patellar tendon reflex reinforcement while mental activity does not a within participants experimental trial
    Chiropractic & Manual Therapies, 2012
    Co-Authors: Steven R Passmore, Paul Bruno
    Abstract:

    The Jendrassik Maneuver (JM) is a remote facilitation muscular contraction shown to affect amplitude and temporal components of the human stretch reflex. Conflicting theoretical models exist regarding the neurological mechanism related to its ability to reinforce reflex parameters. One mechanism involves the gamma motoneurons of the fusimotor system, which are subject to both physical and mental activity. A second mechanism describes reduced alpha motoneuron presynaptic inhibition, which is not subject to mental activity. In the current study, we determined if mental activity could be used to create a reflex facilitation comparable to a remote muscle contraction. Using a within-participants design, we investigated the relative effect of the JM and a successfully employed mental task (Stroop task) on the amplitude and temporal components of the patellar tendon reflex. We found that the addition of mental activity had no influence on the patellar tendon reflex parameters measured, while the JM provided facilitation (increased reflex amplitude, decreased total reflex time). The findings from this study support the view that the mechanism for the JM is a reduction in presynaptic inhibition of alpha motoneurons as it is influenced by physical and not mental activity.

Kemal S Turker - One of the best experts on this subject based on the ideXlab platform.

  • Jendrassik Maneuver effect on spinal and brainstem reflexes
    Experimental Brain Research, 2019
    Co-Authors: Lale A Ertuglu, Hatice Kumru, Josep Vallssole, Asli Aydin, Eloy Opisso, Serpil Cecen, Kemal S Turker
    Abstract:

    The effect of Jendrassik Maneuver (JM) has been extensively studied on monosynaptic reflexes in numerous muscles below the level at which the Maneuver was performed. Here we hypothesize that the effect of JM could be observed also on other reflexes, indicating a widespread influence of performing a motor act such as the JM. We examined polysynaptic reflexes caudal (i.e., the withdrawal reflex of the lower extremities) and rostral (i.e., the blink reflex to supraorbital nerve stimulation) to the level of JM contraction. We have assessed soleus tendon (T) reflex; withdrawal reflex in tibialis anterior and soleus muscle; blink reflex (BR), blink reflex excitability recovery curve (BR-ER) and prepulse inhibition of the blink reflex. Our results showed that (1) T-reflex amplitude increased during JM and decreased just after and 15 min after JM; (2) no change in the withdrawal reflex; (3) R2 area of BR reduced significantly just after or 15 min after JM; (4) Prepulse inhibition in BR reduced significantly during JM; (5) no change in BR-ER. Our results indicate that JM leads to generalized effects on neural excitability at both caudal and rostral levels. Furthermore, JM has a selective effect on excitability of reflex circuitries.

  • Standardization of the Jendrassik Maneuver in Achilles tendon tap reflex
    'Elsevier BV', 2018
    Co-Authors: Lale A Ertuglu, Ilhan Karacan, Gizem Yilmaz, Kemal S Turker
    Abstract:

    Objective: For many decades, the Jendrassik Maneuver (JM) has been used as a reinforcement for stretch reflexes, although the underlying mechanism of this reinforcement is still not fully understood. Moreover, the term JM has been used for many different muscle contraction strategies as there is no fixed movement for the Maneuver in the literature. In this study, we aimed to investigate the effects of clenched hand pull, teeth clenching, and their combined effects to reach standardization. Methods: Achilles tendon tap reflex responses in the soleus were recorded during rest (R), hand pull (HP), teeth clench (TC), and HP + TC combined, hereafter referred to as the JM. Results: Reflex response amplitudes significantly increased during JM, HP, and TC in the soleus. HP and JM significantly changed the background activity in the soleus, but TC alone did not. Conclusion: These results suggest that dominantly presynaptic disinhibitory mechanisms may be responsible for the increase in the tendon tap reflex during HP, TC, and JM. Significance: Because the findings indicate that HP increases the background activity of the soleus, we suggest that researchers should use only TC during the Jendrassik Maneuver to avoid any confounding background activity change. Keywords: Jendrassik Maneuver, Achilles tendon stretch reflex, Reinforcement, Presynaptic disinhibition, Gamma activatio

  • standardization of the Jendrassik Maneuver in achilles tendon tap reflex
    Clinical Neurophysiology Practice, 2018
    Co-Authors: Lale A Ertuglu, Ilhan Karacan, Gizem Yilmaz, Kemal S Turker
    Abstract:

    Abstract Objective For many decades, the Jendrassik Maneuver (JM) has been used as a reinforcement for stretch reflexes, although the underlying mechanism of this reinforcement is still not fully understood. Moreover, the term JM has been used for many different muscle contraction strategies as there is no fixed movement for the Maneuver in the literature. In this study, we aimed to investigate the effects of clenched hand pull, teeth clenching, and their combined effects to reach standardization. Methods Achilles tendon tap reflex responses in the soleus were recorded during rest (R), hand pull (HP), teeth clench (TC), and HP + TC combined, hereafter referred to as the JM. Results Reflex response amplitudes significantly increased during JM, HP, and TC in the soleus. HP and JM significantly changed the background activity in the soleus, but TC alone did not. Conclusion These results suggest that dominantly presynaptic disinhibitory mechanisms may be responsible for the increase in the tendon tap reflex during HP, TC, and JM. Significance Because the findings indicate that HP increases the background activity of the soleus, we suggest that researchers should use only TC during the Jendrassik Maneuver to avoid any confounding background activity change.

Lale A Ertuglu - One of the best experts on this subject based on the ideXlab platform.

  • Jendrassik Maneuver effect on spinal and brainstem reflexes
    Experimental Brain Research, 2019
    Co-Authors: Lale A Ertuglu, Hatice Kumru, Josep Vallssole, Asli Aydin, Eloy Opisso, Serpil Cecen, Kemal S Turker
    Abstract:

    The effect of Jendrassik Maneuver (JM) has been extensively studied on monosynaptic reflexes in numerous muscles below the level at which the Maneuver was performed. Here we hypothesize that the effect of JM could be observed also on other reflexes, indicating a widespread influence of performing a motor act such as the JM. We examined polysynaptic reflexes caudal (i.e., the withdrawal reflex of the lower extremities) and rostral (i.e., the blink reflex to supraorbital nerve stimulation) to the level of JM contraction. We have assessed soleus tendon (T) reflex; withdrawal reflex in tibialis anterior and soleus muscle; blink reflex (BR), blink reflex excitability recovery curve (BR-ER) and prepulse inhibition of the blink reflex. Our results showed that (1) T-reflex amplitude increased during JM and decreased just after and 15 min after JM; (2) no change in the withdrawal reflex; (3) R2 area of BR reduced significantly just after or 15 min after JM; (4) Prepulse inhibition in BR reduced significantly during JM; (5) no change in BR-ER. Our results indicate that JM leads to generalized effects on neural excitability at both caudal and rostral levels. Furthermore, JM has a selective effect on excitability of reflex circuitries.

  • Standardization of the Jendrassik Maneuver in Achilles tendon tap reflex
    'Elsevier BV', 2018
    Co-Authors: Lale A Ertuglu, Ilhan Karacan, Gizem Yilmaz, Kemal S Turker
    Abstract:

    Objective: For many decades, the Jendrassik Maneuver (JM) has been used as a reinforcement for stretch reflexes, although the underlying mechanism of this reinforcement is still not fully understood. Moreover, the term JM has been used for many different muscle contraction strategies as there is no fixed movement for the Maneuver in the literature. In this study, we aimed to investigate the effects of clenched hand pull, teeth clenching, and their combined effects to reach standardization. Methods: Achilles tendon tap reflex responses in the soleus were recorded during rest (R), hand pull (HP), teeth clench (TC), and HP + TC combined, hereafter referred to as the JM. Results: Reflex response amplitudes significantly increased during JM, HP, and TC in the soleus. HP and JM significantly changed the background activity in the soleus, but TC alone did not. Conclusion: These results suggest that dominantly presynaptic disinhibitory mechanisms may be responsible for the increase in the tendon tap reflex during HP, TC, and JM. Significance: Because the findings indicate that HP increases the background activity of the soleus, we suggest that researchers should use only TC during the Jendrassik Maneuver to avoid any confounding background activity change. Keywords: Jendrassik Maneuver, Achilles tendon stretch reflex, Reinforcement, Presynaptic disinhibition, Gamma activatio

  • standardization of the Jendrassik Maneuver in achilles tendon tap reflex
    Clinical Neurophysiology Practice, 2018
    Co-Authors: Lale A Ertuglu, Ilhan Karacan, Gizem Yilmaz, Kemal S Turker
    Abstract:

    Abstract Objective For many decades, the Jendrassik Maneuver (JM) has been used as a reinforcement for stretch reflexes, although the underlying mechanism of this reinforcement is still not fully understood. Moreover, the term JM has been used for many different muscle contraction strategies as there is no fixed movement for the Maneuver in the literature. In this study, we aimed to investigate the effects of clenched hand pull, teeth clenching, and their combined effects to reach standardization. Methods Achilles tendon tap reflex responses in the soleus were recorded during rest (R), hand pull (HP), teeth clench (TC), and HP + TC combined, hereafter referred to as the JM. Results Reflex response amplitudes significantly increased during JM, HP, and TC in the soleus. HP and JM significantly changed the background activity in the soleus, but TC alone did not. Conclusion These results suggest that dominantly presynaptic disinhibitory mechanisms may be responsible for the increase in the tendon tap reflex during HP, TC, and JM. Significance Because the findings indicate that HP increases the background activity of the soleus, we suggest that researchers should use only TC during the Jendrassik Maneuver to avoid any confounding background activity change.

Tatsuya Kasai - One of the best experts on this subject based on the ideXlab platform.

  • facilitation of motor evoked potentials and h reflexes of flexor carpi radialis muscle induced by voluntary teeth clenching
    Human Movement Science, 2002
    Co-Authors: Kenichi Sugawara, Tatsuya Kasai
    Abstract:

    In order to examine the effects of remote facilitation on cortical and spinal sites, we recorded motor evoked potentials (MEPs) and H-reflexes from the flexor carpi radialis muscle of 13 healthy subjects. The H-reflex was used to assess excitability changes at the spinal level, while the MEP following transcranial magnetic stimulation was used to study excitability changes at the cortical level. We induced remote facilitation by means of voluntary teeth clenching (VTC), the so-called Jendrassik Maneuver, because this procedure is known to be effective and reliable. Although the facilitation induced by VTC was observed in both evoked potentials (i.e., H-reflex and MEP), which is consistent with previous reports, MEP onset latencies were shortened by VTC in proportion to an increased MEP amplitude, whereas the latencies of the H-reflex were not. Furthermore, statistically significant relationships between MEP latencies and amplitudes were observed in all subjects, whereas no such relationships were observed for the H-reflex. On the basis of these results, two neural pathways are presumed: one involving a release of pre-synaptic inhibition at the spinal level and the other involving an unmasking of lateral excitatory projections at the cortical level.