Modification of the Stretch Reflex in Spastic Monkeys by Cerebellar Stimulation

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.

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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.

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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

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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.

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Baclofen increases the soleus stretch reflex threshold in the early swing phase during walking in spastic multiple sclerosis patients

Multiple Sclerosis Journal ◽

10.1177/135245850000600209 ◽

2000 ◽

Vol 6 (2) ◽

pp. 105-114 ◽

Cited By ~ 19

Author(s):

Jørgen F Nielsen ◽

Jacob B Anderson ◽

Thomas Sinkjær

Keyword(s):

Multiple Sclerosis ◽

Stretch Reflex ◽

Swing Phase ◽

Modulation Index ◽

Emg Activity ◽

Walking Performance ◽

Linear Fit ◽

Reflex Threshold ◽

Multiple Sclerosis Patients ◽

Velocity Input

The effect of baclofen on walking performance was examined in nine spastic multiple sclerosis patient. In addition, nine healthy subjects were tested as controls. The modulation of the short latency soleus stretch reflex was closer to normal with baclofen compared to the recordings without baclofen, the modulation index being 74% (range: 60-100) with baclofen and 62% (range: 20 -100) without baclofen, P=0.03. In healthy subject the modulation index was 100% (range: 52 -100). In the early swing phase the threshold of the soleus stretch reflex was significantly higher during baclofen medication being 139 degls (range: 63 -302) compared with 93 degls (range: 37-187) with out baclofen, P=0.004. The relation between the stretch velocity (input) and the amplitude of the stretch reflex (output) in early swing phase was unchanged being 0.27 μVs/deg (range: 0.1-1.51) in patient with baclofen and 0.24 μVs/deg (range: 0.08-0.79) without baclofen, P=0.25. Baclofen induced no change in input-output properties of the stretch reflex during walking compared with findings in a sitting position at matched EMG activity. There was a significant correlation between clinical spasticity score and stretch reflex threshold in the early swing phase (p=-0.61, P=0.04) and between clinical spasticity score and the slope of the best linear fit in the early swing phase (p=0.72, P=0.009).

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