The effects of cerebellar stimulation on alpha motoneuron excitability and the stretch reflex in the cat

In cats anesthetized with chloralose-urethane mixture, stimulation of an afferent nerve evoked a vasoconstrictor reflex (VCR) and a galvanic skin response (GSR) in the pads of the feet. Stimulation of the ventromedial medullary reticular substance at the level of the obex abolished the VCR and the GSR. VCR could also be reduced by occlusion during prolonged stimulation of another spinal or visceral afferent pathway. Medulla stimulation was effective without itself causing a sympathetic discharge to the paw, showing that inhibition rather than occlusion was operative. Anterior cerebellar stimulation also inhibited the VCR. Carotid sinus nerve stimulation did not abolish the VCR. It is concluded that the effective mechanism includes a bulbospinal inhibitory path projecting on a spinal vasoconstrictor reflex arc. This arrangement is similar to the descending pathways inhibiting other spinal reflexes but the VCR-inhibitory path can be activated independently of them.

Download Full-text

The critical need to develop tools assessing cerebellar reserve for the delivery and assessment of non-invasive cerebellar stimulation

Cerebellum & Ataxias ◽

10.1186/s40673-020-00126-w ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Mario Manto ◽

Shinji Kakei ◽

Hiroshi Mitoma

Keyword(s):

Daily Practice ◽

Clinical Applications ◽

Non Invasive ◽

Very High ◽

Cerebellar Disorders ◽

Cerebellar Stimulation

AbstractNon-invasive cerebellar stimulation (NICS) aims to modulate cerebello-cerebral loops and cerebro-spinal loops, both for research and clinical applications. It is of paramount importance to establish and validate morphological and functional tools to quantify cerebellar reserve, defined as the capacity for restoration and compensation to pathology of the cerebellum. Using NICS without efforts to estimate cerebellar reserve will end up in conflicting results due to the very high heterogeneity of cerebellar disorders encountered in daily practice.

Download Full-text

The effect of dry needling of myofascial trigger points on muscle stiffness and motoneuron excitability in healthy subjects

Acupuncture in Medicine ◽

10.1177/09645284211027579 ◽

2021 ◽

pp. 096452842110275

Author(s):

Carolina Jiménez-Sánchez ◽

Julio Gómez-Soriano ◽

Elisabeth Bravo-Esteban ◽

Orlando Mayoral-del Moral ◽

Pablo Herrero-Gállego ◽

...

Keyword(s):

Muscle Tone ◽

Intervention Group ◽

Trigger Points ◽

Muscle Stiffness ◽

Invasive Technique ◽

Control Group ◽

Dry Needling ◽

Myofascial Trigger Points ◽

Motoneuron Excitability

Background: Myofascial trigger points (MTrPs) are hypersensitive nodules in a taut band (TB) of skeletal muscle. Dry needling (DN) is an invasive technique recommended for the treatment of MTrPs. However, to our knowledge, no studies have investigated the influence of the DN technique on modification of muscle stiffness and neurophysiological properties of MTrPs. Objective: The objective was to examine the effect of DN on muscle stiffness and motoneuron excitability of a latent medial MTrP (nodule and TB) of the soleus muscle in non-injured subjects. Methods: A double-blinded randomised controlled trial of 46 subjects with latent medial MTrPs of the soleus was conducted, in which all received one session of DN. The intervention group (n = 23) were subjected to DN into the MTrP (the nodule), while the control group (n = 23) were subjected to DN into the TB. Assessment was carried out at baseline (pre-test), after the intervention (post-test) and 1 week after the intervention (follow-up). Biomechanical variables (muscle resistive force at 10°/s and 180°/s, muscle extensibility and strength), as measured with an isokinetic dynamometer, and neurophysiological variables (H-reflex), were recorded. Results: There were no statistically significant differences in biomechanical or neurophysiological assessments between groups. Considering the intra-group analysis, subjects in the intervention group exhibited increased maximal isometric voluntary force to ankle plantarflexion (MIVFp) at both post-intervention and follow-up assessment (p < 0.0125; 0.2 < d < 0.5), while no changes were found in the control group. Conclusion: One session of DN targeting latent MTrPs did not change muscle stiffness, muscle extensibility or motoneuron excitability. Further research on subjects with muscle tone disorders should be considered to better address the impact of DN on muscle tone. Trial registration number: NCT02575586 (ClinicalTrials.gov).

Download Full-text

Factors which Modify the Short and Long Latency Components of the Stretch Reflex in the Human Forearm

Motor Control ◽

10.1007/978-1-4615-7508-5_8 ◽

1987 ◽

pp. 43-50

Author(s):

R. G. Lee ◽

R. Hayashi ◽

W. Becker

Keyword(s):

Stretch Reflex ◽

Long Latency ◽

Human Forearm

Download Full-text

Statistical Considerations When Assessing Short Latency Stretch Reflexes in the Human Soleus Muscle

Motor Control ◽

10.1123/mc.2013-0095 ◽

2015 ◽

Vol 19 (4) ◽

pp. 253-270 ◽

Cited By ~ 3

Author(s):

Asger Roer Pedersen ◽

Peter William Stubbs ◽

Jørgen Feldbæk Nielsen

Keyword(s):

Ankle Joint ◽

Soleus Muscle ◽

Stretch Reflex ◽

Short Latency ◽

Response Magnitude ◽

Variance Heterogeneity ◽

Stretch Reflexes ◽

Response Characteristics ◽

Normally Distributed

The aim was to investigate trial-by-trial response characteristics in the short-latency stretch reflex (SSR). Fourteen dorsiflexion stretches were applied to the ankle joint with a precontracted soleus muscle on 2 days. The magnitude and variability of trial-by-trial responses of the SSR were assessed. The SSR was log-normally distributed and variance heterogeneous between subjects. For some subjects, the magnitude and variance differed between days and stretches. As velocity increased, variance heterogeneity tended to decrease and response magnitude increased. The current study demonstrates the need to assess trial-by-trial response characteristics and not averaged curves. Moreover, it provides an analysis of SSR characteristics accounting for log-normally distributed and variance heterogeneous trial-by-trial responses.

Download Full-text