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Experimental Brain Research 1990In parallel experiments on humans and in the cat it was investigated how the sensitivity of monosynaptic test reflexes to facilitation and inhibition varies as a... (Comparative Study)
Comparative Study
In parallel experiments on humans and in the cat it was investigated how the sensitivity of monosynaptic test reflexes to facilitation and inhibition varies as a function of the size of the control test reflex itself. In man the monosynaptic reflex (the Hoffmann reflex) was evoked in either the soleus muscle (by stimulation of the tibial nerve) or the quadriceps muscle (by stimulation of the femoral nerve). In the decerebrate cat monosynaptic reflexes were recorded from the nerves to soleus and medial gastrocnemius muscles; they were evoked by stimulation of the proximal ends of the sectioned L7 and S1 dorsal roots. Various excitatory and inhibitory spinal reflex pathways were used for conditioning the test reflexes (e.g. monosynaptic Ia excitation, disynaptic reciprocal inhibition, cutaneous inhibition, recurrent inhibition, presynaptic inhibition of the Ia fibres mediating the test reflex). It was shown that the additional number of motoneurones recruited in a monosynaptic test reflex by a constant excitatory conditioning stimulus was very much dependent on the size of the test reflex itself. This dependency had the same characteristic pattern whatever the conditioning stimulus. With increasing size of the test reflex the number of additionally recruited motoneurones first increased, then reached a peak (or plateau) and finally decreased. A similar relation was also seen with inhibitory conditioning stimuli. The basic physiological factors responsible for these findings are discussed. Finally, the implications for the interpretation of experiments in man with the H-reflex technique are considered.
Topics: Adolescent; Adult; Animals; Cats; Conditioning, Operant; Decerebrate State; Electric Stimulation; Humans; Middle Aged; Reflex, Monosynaptic; Species Specificity
PubMed: 2394229
DOI: 10.1007/BF00230098 -
Journal of Neurosurgical Anesthesiology Jan 2014
Topics: Glycerol; Humans; Male; Middle Aged; Monitoring, Intraoperative; Neurosurgical Procedures; Reflex; Reflex, Trigeminocardiac; Spinal Nerve Roots; Syncope, Vasovagal; Trigeminal Neuralgia
PubMed: 23686106
DOI: 10.1097/ANA.0b013e318297f96a -
Journal of Neurology, Neurosurgery, and... Sep 1982The Hoffmann reflex and the Achilles tendon reflex were measured in a group of 194 subjects suspected of having a lumbosacral root compression syndrome. The Achilles...
The Hoffmann reflex and the Achilles tendon reflex were measured in a group of 194 subjects suspected of having a lumbosacral root compression syndrome. The Achilles tendon reflex was elicited manually with a metal hammer. There was a high correlation between the H-M interval and the Achilles tendon reflex-M interval. The usefulness of the Achilles tendon reflex was evaluated in a selected sub-group of 61 patients with proven L5 or S1 root compression. Neither the H-reflex nor the Achilles tendon reflex appeared to be of any value in detecting L5 root compression. Both the H-reflex and the Achilles tendon reflex proved to be useful for diagnosis of S1 root compression syndromes, the latter being the more sensitive method.
Topics: Achilles Tendon; Electric Stimulation; H-Reflex; Humans; Intervertebral Disc Displacement; Muscle Contraction; Muscles; Nerve Compression Syndromes; Reflex, Stretch; Spinal Nerve Roots; Tibial Nerve
PubMed: 7131012
DOI: 10.1136/jnnp.45.9.791 -
The Journal of Physiology Mar 19781. The sacral parasympathetic outflow to the large intestine of the cat was studied by monitoring simultaneously intestinal motility and the efferent firing in...
1. The sacral parasympathetic outflow to the large intestine of the cat was studied by monitoring simultaneously intestinal motility and the efferent firing in postganglionic fibres on the serosal surface of the mid-distal colon. 2. Increases in efferent firing were noted during the occurrence of spontaneous propulsive activity (tonic pressure waves) or segmental contractions (slow rhythmic pressure waves). The neural discharge was not altered by transection of the lumbar sympathetic innervation to the colon but was blocked by interruption of the sacral parasympathetic outflow. 3. Electrical stimulation of pelvic nerve afferents arising in the colon or distension of the colon or rectum evoked reflex increases in efferent firing and sustained propulsive contractions that were associated with defaecation. Both responses were abolished by transection of the pelvic nerves or sacral dorsal roots. 4. Electrical stimulation of colonic afferent fibres also evoked synchronous reflex discharges in colonic efferents at latencies ranging from 180 to 300 msec. The discharges were enhanced during propulsive contractions, abolished by transection of the pelvic nerves but not altered by transection of the lumbar sympathetic nerves. 5. Sacral reflexes were present in cats with intact spinal cord and in chronic spinal animals (transection at T10-T12). The reflexes recovered within minutes to several hours after acute transection of the spinal cord. 6. Electrophysiological measurements indicated that the sacral reflexes to the large intestine were mediated by non-myelinated afferent and preganglionic efferent fibres. The central delay for the reflex was estimated to be 45-60 msec. 7. It is concluded that the sacral parasympathetic reflexes to the large intestine are mediated via a spinal pathway and have an essential role in the initiation of propulsive activity during defaecation.
Topics: Animals; Cats; Colon; Defecation; Evoked Potentials; Female; Gastrointestinal Motility; Male; Muscle, Smooth; Neurons, Afferent; Neurons, Efferent; Parasympathetic Nervous System; Rectum; Reflex
PubMed: 650474
DOI: 10.1113/jphysiol.1978.sp012248 -
American Journal of Physiology. Heart... Sep 2004It has been suggested that the midbrain periaqueductal gray (PAG) is a neural integrating site for the interaction between the muscle pressor reflex and the arterial...
It has been suggested that the midbrain periaqueductal gray (PAG) is a neural integrating site for the interaction between the muscle pressor reflex and the arterial baroreceptor reflex. The underlying mechanisms are poorly understood. The purpose of this study was to examine the roles of GABA and nitric oxide (NO) in modulating the PAG integration of both reflexes. To activate muscle afferents, static contraction of the triceps surae muscle was evoked by electrical stimulation of the L7 and S1 ventral roots of 18 anesthetized cats. In the first group of experiments (n = 6), the pressor response to muscle contraction was attenuated by bilateral microinjection of muscimol (a GABA receptor agonist) into the lateral PAG [change in mean arterial pressure (DeltaMAP) = 24 +/- 5 vs. 46 +/- 8 mmHg in control]. Conversely, the pressor response was significantly augmented by 0.1 mM bicuculline, a GABAA receptor antagonist (DeltaMAP = 65 +/- 10 mmHg). In addition, the effect of GABAA receptor blockade on the reflex response was significantly blunted after sinoaortic denervation and vagotomy (n = 4). In the second group of experiments (n = 8), the pressor response to contraction was significantly attenuated by microinjection of L-arginine into the lateral PAG (DeltaMAP = 26 +/- 4 mmHg after L-arginine injection vs. 45 +/- 7 mmHg in control). The effect of NO attenuation was antagonized by bicuculline and was reduced after denervation. These data demonstrate that GABA and NO within the PAG modulate the pressor response to muscle contraction and that NO attenuation of the muscle pressor reflex is mediated via arterial baroreflex-engaged GABA increase. The results suggest that the PAG plays an important role in modulating cardiovascular responses when muscle afferents are activated.
Topics: Animals; Arteries; Baroreflex; Bicuculline; Blood Pressure; Cats; Female; GABA Agonists; GABA Antagonists; GABA-A Receptor Antagonists; Male; Mesencephalon; Motor Activity; Muscimol; Muscle Contraction; Muscle, Skeletal; Nitric Oxide; Periaqueductal Gray; Reflex; gamma-Aminobutyric Acid
PubMed: 15087292
DOI: 10.1152/ajpheart.00163.2004 -
Muscle & Nerve Oct 2009Muscle stretch reflexes (MSRs) are fundamental to the neurologic examination. Although the fifth, sixth, and seventh cervical roots have appropriate and easily elicited...
Muscle stretch reflexes (MSRs) are fundamental to the neurologic examination. Although the fifth, sixth, and seventh cervical roots have appropriate and easily elicited MSRs, the C8 level does not. The C8 reflex is obtained by tapping the thenar eminence, which produces flexion at the interphalyngeal joints of the fingers. To confirm that finger flexion represented an MSR, an externally triggered hammer-skin contact set-up was employed. Surface recording electrodes were placed at one third of the distance between the medial epicondyle and ulnar styloid. This montage produced distinct T-waves with latencies compatible with a reflex arc. Normative data were collected for 75 healthy subjects (150 arms), including 15 from each of five age groups (20-29, 30-39, 40-49, 50-59, > or =60 years). Distance 1 (D1) was measured from the FPL to the C7 spinous process and distance 2 (D2) from C7 to the G1 electrode. A high median neuropathy abolished the T-wave. A distal median nerve block at the carpal tunnel had no effect. Mean latencies (+/- SD) from the respective age groups were as follows: 21.73 +/- 1.16 ms; 22.50 +/- 1.70 ms; 22.19 +/- 1.52 ms; 22.66 +/- 2.13 ms; and 23.97 +/- 1.91 ms. Reflex latencies significantly correlated with age (r = 0.33, P = 0.004), height (r = 0.51, P < 0.0001), and D1 + D2 or arc length (r = 0.74, P < 0.0001). This novel MSR is generated from the FPL tendon and stimulates contraction of the long finger flexors. It therefore represents a clinically useful C8 MSR.
Topics: Adult; Aged; Aged, 80 and over; Aging; Electrodes; Female; Fingers; Functional Laterality; Humans; Joints; Male; Middle Aged; Muscle, Skeletal; Neural Conduction; Physical Stimulation; Reference Values; Reflex, Stretch; Young Adult
PubMed: 19623633
DOI: 10.1002/mus.21338 -
The Journal of Pharmacology and... Nov 1984The in situ segmental spinal reflex system of the rat was used to determine changes in excitatory and inhibitory synaptic function associated with benzodiazepine...
The in situ segmental spinal reflex system of the rat was used to determine changes in excitatory and inhibitory synaptic function associated with benzodiazepine tolerance, physical dependence and withdrawal. Rats were made physically dependent on chlordiazepoxide using a chronically equivalent dosing method. After spinalization, dorsal and ventral lumbar roots (L5 or L6) were isolated for extracellular stimulation and recording. Testing of spinal function was performed during peak withdrawal (8 days) and at peak effect (4 hr) after first ("acute") and last ("chronic") dose of chronically equivalent chlordiazepoxide. There were no quantitative or qualitative differences in the acute and chronic spinal actions of chlordiazepoxide. Polysynaptic discharges were markedly augmented during withdrawal (159% above control) and diminished during treatment (44% below control). Recovery of the 2 N reflex measured by twin pulse was shortened during withdrawal (23% above control) and lengthened during treatment (28% below control). Recovery of the 2 N reflex analyzed by low-frequency (10 Hz) stimulation was also elevated at peak withdrawal (40% above control) and depressed in treatment (41% below control). At peak withdrawal spinal inhibitions were reduced below control; presynaptic-dorsal root reflex (60%) and recurrent (62%). In contrast, drug treatment enhanced presynaptic (72%) and recurrent (48%) inhibitions above control. Only those synaptic parameters chronically altered by continuous chlordiazepoxide administration were oppositely affected during withdrawal. Consequently, benzodiazepine withdrawal is associated with rebound alterations of profound reductions in inhibitory synaptic transmission, increased net polysynaptic activity and shortened monosynaptic recovery times.
Topics: Animals; Barbiturates; Benzodiazepines; Drug Tolerance; Humans; Male; Rats; Rats, Inbred Strains; Receptors, GABA-A; Reflex; Spinal Cord; Substance Withdrawal Syndrome; Substance-Related Disorders; Synapses; Synaptic Transmission
PubMed: 6092620
DOI: No ID Found -
Journal of Clinical Neurophysiology :... Jan 1996The sacral cord conduction time of the soleus H-reflex was investigated in 30 normal adult subjects using three different methods. (1) The posterior tibial nerve was...
The sacral cord conduction time of the soleus H-reflex was investigated in 30 normal adult subjects using three different methods. (1) The posterior tibial nerve was stimulated at the popliteal fossa by graded electric shocks, and the recordings were made from different lumbar epidural intervertebral levels. The afferent action potentials from the dorsal roots and the reflexively evoked efferent action potentials from the ventral roots were recorded. The time interval between the negative peaks of the ventral and dorsal root potentials was used to calculate the approximate sacral cord reflex delay time, which was found to be 1.3 ms. on average. (2) The sacral cord reflex delay time was found to be about 2.0 ms using the conduction time of the afferent, that of the efferent limbs and total reflex time of the soleus H-response. (3) By stimulating the lumbosacral roots at the epidural levels and using the difference between the soleus H and M response latencies, the sacral cord reflex delay was determined to be approximately 2.4 ms. These findings indicated that the soleus H-reflex is exclusively monosynaptic. It is proposed that in humans the synaptic transmission at the sacral cord is approximately 0.4 ms.
Topics: Adult; Afferent Pathways; Electric Stimulation; Electromyography; Female; Ganglia, Spinal; H-Reflex; Humans; Male; Middle Aged; Muscle, Skeletal; Reaction Time; Reference Values; Reflex, Monosynaptic; Spinal Cord; Tibial Nerve
PubMed: 8988288
DOI: 10.1097/00004691-199601000-00008 -
Journal of Neurophysiology May 1958
Topics: Ganglia, Spinal; Reflex; Spinal Nerve Roots; Spinal Nerves
PubMed: 13539658
DOI: 10.1152/jn.1958.21.3.217 -
Neurourology and Urodynamics Jun 2017To investigate the effects of electrical stimulation of sacral dorsal/ventral roots on irritation-induced bladder overactivity, reveal possible different mechanisms...
AIMS
To investigate the effects of electrical stimulation of sacral dorsal/ventral roots on irritation-induced bladder overactivity, reveal possible different mechanisms under nociceptive bladder conditions, and establish a large animal model of sacral neuromodulation.
METHODS
Intravesical infusion of 0.5% acetic acid (AA) was used to irritate the bladder and induce bladder overactivity in cats under α-chloralose anesthesia. Electrical stimulation (5, 15, or 30 Hz) was applied to individual S1-S3 dorsal or ventral roots at or below motor threshold intensity. Repeated cystometrograms (CMGs) were performed with/without the stimulation to determine the inhibition of bladder overactivity.
RESULTS
AA irritation induced bladder overactivity and significantly (P < 0.05) reduced the bladder capacity to 62.6 ± 11.7% of control capacity measured during saline CMGs. At threshold intensity for inducing reflex twitching of the anal sphincter or toe, S1/S2 dorsal root stimulation at 5 Hz but not at 15 or 30 Hz inhibited bladder overactivity and significantly (P < 0.05) increased bladder capacity to 187.3 ± 41.6% and 155.5 ± 9.7% respectively, of AA control capacity. Stimulation of S3 dorsal root or S1-S3 ventral roots was not effective. Repeated stimulation of S1-S3 dorsal root did not induced a post-stimulation inhibition.
CONCLUSIONS
This study established a cat model of sacral neuromodualation of nociceptive bladder overactivity. The results revealed that the mechanisms underlying sacral neuromodulation are different for nociceptive and non-nociceptive bladder activity.
Topics: Acetic Acid; Animals; Cats; Disease Models, Animal; Electric Stimulation Therapy; Female; Male; Reflex; Sacrum; Spinal Nerve Roots; Urinary Bladder, Overactive
PubMed: 27571328
DOI: 10.1002/nau.23105