Neck muscle and trigeminal input to the upper cervical cord and lower medulla of the cat

1979 ◽  
Vol 57 (6) ◽  
pp. 642-651 ◽  
Author(s):  
V. C. Abrahams ◽  
G. Anstee ◽  
F. J. R. Richmond ◽  
P. K. Rose
Keyword(s):  
Muscle Afferents ◽  
Ventral Horn ◽  
Cervical Cord ◽  
High Threshold ◽  
Neck Muscle ◽  
Afferent Projections ◽  
Muscle Afferent ◽  
Upper Cervical ◽  
Deep Layers ◽  
Neck Muscle Afferents

Experiments on chloralose-anaesthetized cats have shown that low-threshold neck muscle afferents project to laminae IV and V in the dorsal horn of the upper cervical cord, to lamina VI including the region which encompasses the central cervical nucleus, as well as to extensive regions of the ventral horn. At posterior medullary levels projections also exist to laminae IV, V, and VI of the spinal nucleus of V (although those to lamina IV are circumscribed), to the deep layers and lateral margin of the cuneate nucleus, and to the inferior olive. These projections are both from low- and high-threshold afferents. Evidence of a functional relationship between the trigeminal and neck muscle afferent system was found both in the upper cervical cord and lower medulla. About 40% of units in both regions receive a convergent input and when convergence could not be demonstrated, prior stimulation of one modality in some instances affected the responsiveness of the unit to the other modality. A motor role was found for some trigeminal afferent projections to the upper cervical cord. Trigeminal afferents consistently activated antidromically identified motoneurons of splenius, biventer cervicis, and complexus.

Projections of extraocular, neck muscle, and retinal afferents to superior colliculus in the cat: their connections to cells of origin of tectospinal tract

1975 ◽  
Vol 38 (1) ◽  
pp. 10-18 ◽  
Author(s):  
V. C. Abrahams ◽  
P. K. Rose
Keyword(s):  
Superior Colliculus ◽  
Extraocular Muscle ◽  
Stimulus Presentation ◽  
Muscle Afferents ◽  
Neck Muscle ◽  
Long Latency ◽  
Cells Of Origin ◽  
Muscle Afferent ◽  
Deep Layers ◽  
Neck Muscle Afferents

Unit recordings were made in the superior colliculus of cats anesthetized with chloralose and with Pentothal. Electrical stimulation of extraocular muscle afferents and neck muscle afferents excited more units in the superior colliculus than did a variety of moving and stationary visual stimuli. Units responding to neck muscle afferent stimulation fell into three populations; one population firing with a short latency and following stimulus presentation up to 1/s, a second population with a long latency and following stimulus presentation at frequencies lower than 15/min, and a third population exhibiting paired firing. The latencies and firing patterns of the third population combined the characteristics of each of the first two patterns. It is suggested that these characteristics of unit discharges stem from the existence of two pathways from neck muscle afferents to the superior colliculus. The projection is predominantly bilateral. Units responding to neck muscle afferent stimulation are distributed throughout the superior colliculus on the basis of their latencies. Long-latency responses predominate in the superficial layers of the superior colliculus and short-latency responses, while more common in the intermediate and deep layers, predominate in the tegmentum. Extraocular muscle afferent projections to the superior colliculus constitute the single richest projection found in these experiments. While the response patterns and latencies are similar to those of the neck muscle afferents, long-latency responses are the most common and dominate in all collicular regions. Few units in the tegmentum could be excited by extraocular muscle afferents. Both extraocular muscle and neck muscle afferents show considerable convergence with one another and with retinal afferents within the superior colliculus. Cells of origin of the tectospinal tract were identified within the superior colliculus and tegmentum by antidromic excitation from the upper cervical cord. These cells were distributed predominantly within the intermediate and deep layers of the superior colliculus, and sparsely in the superficial layers and tegmentum. Almost 50% of the cells of origin of the tectospinal tract receive a convergent input from extraocular muscle and neck muscle afferents and from the retina. About 30% of the cells were inexcitable to the stimuli employed in these experiments. The significance of these projections is discussed with respect to superior collicular function in the cat and i

Noradrenergic synapses and effects of noradrenaline on interneurons in the ventral horn of the cat spinal cord

1977 ◽  
Vol 55 (3) ◽  
pp. 399-412 ◽  
Author(s):  
Larry M. Jordan ◽  
David A. McCrea ◽  
John D. Steeves ◽  
John E. Menzies
Keyword(s):  
Spinal Cord ◽  
Close Contact ◽  
Cell Types ◽  
Muscle Afferents ◽  
Ventral Horn ◽  
Lumbar Spinal Cord ◽  
High Threshold ◽  
Depressant Action ◽  
Motor Nuclei ◽  
Lumbar Spinal

Histochemical and electrophysiological procedures were carried out to determine the cell types in the ventral horn which are in close contact with noradrenergic terminals and to identify the types of neurons in the ventral horn which are influenced by noradrenaline (NA). Fluorescence histochemical studies revealed that noradrenaline-containing fibers rarely form intimate contacts with alpha motoneurons, whereas many small interneurons which are closely invested with fluorescent fibers can be found near the motoneurons. The effects of microiontophoretically applied NA on interneurons were examined in the lateral motor areas of the lumbar spinal cord ventral horn. NA had a substantial depressant action on 43% of cells in chloralose-anesthetized and decerebrate cats; it excited 6% of the cells, and was without effect on the rest. The cells which were depressed by NA could be excited by electrical stimulation of high threshold muscle afferents or skin afferents, and they could be influenced from a variety of exteroceptive and proprioceptive inputs. Owing to considerable convergence on the affected interneurons, no distinct population of NA-sensitive interneurons could be identified. Many of the interneurons strongly depressed by NA were found near the motor nuclei. The hypothesis is presented that inhibitory actions of NA on interneurons in the motor nuclei might explain its hyperpolarizing action on motoneurons.

Vestibulospinal effects on neurons in different regions of the gray matter of the cat upper cervical cord

1996 ◽  
Vol 76 (4) ◽  
pp. 2439-2446 ◽  
Author(s):  
N. Isu ◽  
D. B. Thomson ◽  
V. J. Wilson
Keyword(s):  
Gray Matter ◽  
Vestibular Nuclei ◽  
Afferent Input ◽  
Ventral Horn ◽  
Cervical Cord ◽  
Cuneate Nucleus ◽  
External Cuneate Nucleus ◽  
Upper Cervical ◽  
Neck Motoneurons ◽  
Stimulation Of

1. Previous studies of vestibular effects on the upper cervical cord have concentrated on the lateral and medial vestibulospinal tracts and on the actions that they exert on neck motoneurons and other neurons in the ventral horn. It is known, however, that both the rostral and the caudal areas of the vestibular nuclei (VN) give rise to axons that are located in the dorsal and dorsolateral funiculi and that terminate in the dorsal horn. A primary goal of our experiments was to investigate the effect of VN stimulation on neurons dorsal to lamina VII. 2. In decerebrate cats with the caudal cerebellar vermis removed, we stimulated different areas of the VN with an array of electrode. The area of stimulation extended from the caudal tip of the descending nucleus to Deiters' nucleus, and was divided into rostral and caudal halves with the use of the descending nucleus as a reference. For control purposes some stimulating points were placed in the external cuneate nucleus and restiform body. 3. We tested the effects of VN stimulation on spontaneously firing neurons in the ipsilateral C2 and C3 segments. For purposes of classification the gray matter was divided into four zones corresponding approximately to laminae 1-IV, V-VI, VII, and VIII of Rexed. Overall, the activity of 39 of 84 neurons was influenced from one or more stimulating sites. For six cells there was some possibility of current spread to the external cuneate nucleus or to the underlying reticular formation. 4. VN-evoked effects could consist of facilitation, or, less often, inhibition. In the majority of facilitated neurons conditioning stimuli evoked a synchronized, short-latency, increase in firing probability. When evoked by single stimuli this facilitation was considered monosynaptic. Facilitation that was diffuse, or that was only evoked by two or more stimuli, presumably involved more complex pathways. The latency of inhibition could not be measured, but was short. 5. Stimulation of either the rostral or caudal VN had no effect on neurons in laminae I-IV. Electrodes placed rostrally had little effect on neurons in laminae V-VI, but influenced more than half the neurons in laminae VII-VIII. Conversely, electrodes placed caudally were most effective on cells in laminae V-VII, although they also influenced some neurons in lamina VIII. 6. Stimulation of the dorsal rami influenced most neurons in laminae V-VI, and about a quarter of the neurons in laminae VII-VIII. When tested, there was often convergence between vestibulospinal and peripheral inputs. 7. Our results provide physiological evidence that vestibulospinal fibers influence neurons not only in laminae VII and VIII, but also as far dorsally as lamina V. Fibers that influence neurons in laminae V and VI originate primarily in the caudal areas of the VN. As suggested previously on anatomic grounds, the projection to the dorsal laminae, which is predominantly facilitatory, often converges with afferent input and can therefore modulate its influence on spinal neurons.

Neck afferents and muscle sympathetic activity in humans: implications for the vestibulosympathetic reflex

1998 ◽  
Vol 84 (2) ◽  
pp. 450-453 ◽  
Author(s):  
Chester A. Ray ◽  
Keith M. Hume
Keyword(s):  
Heart Rate ◽  
Vestibular System ◽  
Sympathetic Activity ◽  
Head Rotation ◽  
Muscle Afferents ◽  
Neck Muscle ◽  
Neck Flexion ◽  
Vestibulosympathetic Reflex ◽  
Neck Afferents ◽  
Neck Muscle Afferents

Ray, Chester A., and Keith M. Hume. Neck afferents and muscle sympathetic activity in humans: implications for the vestibulosympathetic reflex. J. Appl. Physiol. 84(2): 450–453, 1998.—We have shown previously that head-down neck flexion (HDNF) in humans elicits increases in muscle sympathetic nerve activity (MSNA). The purpose of this study was to determine the effect of neck muscle afferents on MSNA. We studied this question by measuring MSNA before and after head rotation that would activate neck muscle afferents but not the vestibular system (i.e., no stimulation of the otolith organs or semicircular canals). After a 3-min baseline period with the head in the normal erect position, subjects rotated their head to the side (∼90°) and maintained this position for 3 min. Head rotation was performed by the subjects in both the prone ( n = 5) and sitting ( n = 6) positions. Head rotation did not elicit changes in MSNA. Average MSNA, expressed as burst frequency and total activity, was 13 ± 1 and 13 ± 1 bursts/min and 146 ± 34 and 132 ± 27 units/min during baseline and head rotation, respectively. There were no significant changes in calf blood flow (2.6 ± 0.3 to 2.5 ± 0.3 ml ⋅ 100 ml−1 ⋅ min−1; n = 8) and calf vascular resistance (39 ± 4 to 41 ± 4 units; n = 8). Heart rate (64 ± 3 to 66 ± 3 beats/min; P = 0.058) and mean arterial pressure (90 ± 3 to 93 ± 3; P < 0.05) increased slightly during head rotation. Additional neck flexion studies were performed with subjects lying on their side ( n = 5). MSNA, heart rate, and mean arterial pressure were unchanged during this maneuver, which also does not engage the vestibular system. HDNF was tested in 9 of the 13 subjects. MSNA was significantly increased by 79 ± 12% ( P < 0.001) during HDNF. These findings indicate that neck afferents activated by horizontal neck rotation or flexion in the absence of significant force development do not elicit changes in MSNA. These findings support the concept that HDNF increases MSNA by the activation of the vestibular system.

scholarly journals Neck muscle afferents influence oromotor and cardiorespiratory brainstem neural circuits

2014 ◽  
Vol 220 (3) ◽  
pp. 1421-1436 ◽  
Author(s):  
I. J. Edwards ◽  
V. K. Lall ◽  
J. F. Paton ◽  
Y. Yanagawa ◽  
G. Szabo ◽  
...  
Keyword(s):  
Neural Circuits ◽  
Muscle Afferents ◽  
Neck Muscle ◽  
Neck Muscle Afferents

Response Properties of TMJ Units in Superficial Laminae at the Spinomedullary Junction of Female Rats Vary Over the Estrous Cycle

2003 ◽  
Vol 89 (3) ◽  
pp. 1467-1477 ◽  
Author(s):  
K. Okamoto ◽  
H. Hirata ◽  
S. Takeshita ◽  
D. A. Bereiter
Keyword(s):  
Estrous Cycle ◽  
Dynamic Range ◽  
Response Duration ◽  
Female Rats ◽  
Mustard Oil ◽  
Cervical Cord ◽  
High Threshold ◽  
Sample Population ◽  
Upper Cervical ◽  
Nociceptive Input

Neurons responsive to stimulation of the temporomandibular joint (TMJ) region were recorded from superficial laminae at the trigeminal subnucleus caudalis/upper cervical cord (Vc/C2) junction region of cycling female rats under barbiturate anesthesia. To determine if receptive field (RF) properties or sensitivity to algesic chemicals of TMJ units vary over the estrous cycle, animals were selected from proestrous (high estrogen) or early diestrous (low estrogen) stages. More than 90% of TMJ units from each group received convergent nociceptive input [wide dynamic range (WDR) or nociceptive specific (NS)-like] from facial skin. The cutaneous high-threshold RF areas of WDR units from proestrous rats were 30% larger than diestrous units, while RF areas of NS units were similar. Bradykinin (BK, 0.1–10 μM) injection into the TMJ region excited a high percentage of units (>80% of total) from both groups in a dose-related manner. However, BK-evoked response magnitude ( R mag, +140%) and duration (+64%) were greater for proestrous than diestrous units. Both WDR and NS-like TMJ units of proestrous females displayed enhanced BK-evoked R mag values and response duration. Glutamate or mustard oil excitation of TMJ units was not affected by stage of the estrous cycle. Several TMJ units from proestrous and diestrous females were activated antidromically from the contralateral posterior thalamus, indicating that projection and nonprojection units were included in the sample population. These results were consistent with the hypothesis that factors related to stage of the estrous cycle modify the processing of deep craniofacial inputs by superficial dorsal horn neurons at the spinomedullary junction, a key region for the initial integration of sensory signals from the TMJ.

Identification of muscle afferents subserving sensation of deep pain in humans

1994 ◽  
Vol 72 (2) ◽  
pp. 883-889 ◽  
Author(s):  
D. A. Simone ◽  
P. Marchettini ◽  
G. Caputi ◽  
J. L. Ochoa
Keyword(s):  
Conduction Velocity ◽  
Receptive Fields ◽  
Extensor Tendon ◽  
Common Peroneal Nerve ◽  
Muscle Afferents ◽  
Group Iv ◽  
High Threshold ◽  
Group Iii ◽  
Muscle Afferent ◽  
Afferent Unit

1. Intraneural microstimulation (INMS) and microneurography were used in combination to stimulate and record from muscle nociceptor primary afferent fibers of the common peroneal nerve of healthy volunteers. When pain evoked by INMS was projected to muscle, afferent activity could be evoked by innocuous and noxious pressure applied within the projected painful area. Conduction velocity of single fibers was determined by stimulating the receptive fields (RFs) electrically via needle electrodes inserted into the RF and measuring conduction latency and distance between the RF and recording electrode. 2. Pain projected to muscle during INMS trains 5–10 s in duration at threshold intensity for pain sensation was typically described as cramping and was well localized. Subjects mapped the area of the painful projected field (PF) over the skin using a pointer. 3. Fourteen slowly adaping mechanoreceptors with RF in muscle and with moderate to high receptor threshold were identified within or near the painful PF. Conduction velocities were in the range of Group III (n = 8) and Group IV (n = 6) fibers. Mean RF areas of Group III and Group IV afferents, determined by applying pressure percutaneously, were 2.71 +/- 1.14 (SE) cm2 and 3.40 +/- 1.08 (SE) cm2, respectively. Only one Group III afferent unit exhibited spontaneous activity (< 1 Hz). 4. One additional high-threshold mechanoreceptor was identified, with its RF located in the extensor tendon at the base of the big toe. This fiber had a conduction velocity of 32 m/s. During INMS, a well-localized sharp pain was projected to the tendon.(ABSTRACT TRUNCATED AT 250 WORDS)

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