Tonic neck reflex of the decerebrate cat: a role for propriospinal neurons

1985 ◽  
Vol 54 (4) ◽  
pp. 978-987 ◽  
Author(s):  
E. E. Brink ◽  
I. Suzuki ◽  
S. J. Timerick ◽  
V. J. Wilson
Keyword(s):  
Decerebrate Cat ◽  
Entry Zone ◽  
Root Entry Zone ◽  
Upper Cervical ◽  
Dorsal Columns ◽  
Qualitative Effect ◽  
Neck Rotation ◽  
Propriospinal Neurons ◽  
Tonic Neck Reflex

In decerebrate, acutely labyrinthectomized cats we used neck rotation to study the role of direct upper cervical afferents to the cervical enlargement and of cervical and lumbar propriospinal neurons in the tonic neck reflex. Interruption of the dorsal columns between C4 and C5 had no qualitative effect on the dynamics of the reflex although gain usually increased. Direct upper cervical afferents to the cervical enlargement therefore have no unique role in producing the reflex. Many medially located propriospinal neurons in C4 were modulated by neck rotation. About 40% had axons, mostly crossed, that terminated in the cervical enlargement. The others projected more caudally, some as far as L3-L4 or even the lumbar enlargement. For a population of C4 neurons, including propriospinal neurons, we measured the response vector with combinations of roll and pitch stimuli. These vectors ranged from pitch to roll. Many propriospinal neurons in L3-L4, projecting to the lumbosacral enlargement, were also modulated by neck rotation with a variety of response vectors. Some of these neurons had an ascending projection. As in previous experiments, C4 neurons were modulated by neck rotation after spinal transection rostral to the C1 dorsal root entry zone; a wide variety of response vectors was observed. In contrast, almost no modulated L3-L4 neurons were found in the same experiments. The results suggest a role for propriospinal neurons in the tonic neck reflex. They also demonstrate that responses of lumbar neurons to neck rotation are much more dependent on supraspinal pathways than are those of cervical neurons.

The spinal projection of individual identified A-delta- and C-fibers

1988 ◽  
Vol 59 (1) ◽  
pp. 41-55 ◽  
Author(s):  
R. J. Traub ◽  
L. M. Mendell
Keyword(s):  
Conduction Velocity ◽  
Dorsal Root ◽  
High Threshold ◽  
Entry Zone ◽  
Root Entry Zone ◽  
C Fibers ◽  
Spinal Projection ◽  
Dorsal Columns ◽  
Adequate Stimulus ◽  
Low Threshold

1. Recordings were made from individual sensory neurons with an A-delta peripheral conduction velocity, either intrasomally in the L7 dorsal root ganglion, or extracellularly in Lissauer's Tract or in the dorsal root close to the root entry zone. The spinal projection of these afferents was assessed by their antidromic response to stimulation of the dorsal columns (DC) or Lissauer's Tract (LT) at the L5/L6 border. The adequate stimulus was also ascertained. 2. A-delta-fibers could be divided into two groups: high-threshold mechanoreceptors from either skin or muscle (HTMRs) and low-threshold mechanoreceptors (LTMs), primarily Down Hairs. A third group of cells recorded intrasomally had broad spikes with shoulders on the downstroke characteristic of A-delta-nociceptors and were so classified provisionally, although no adequate stimulus could be identified. HTMRs and broad spike cells projected either in DC or LT, but LTMs projected only in DC, never in LT. About one-quarter of both groups failed to project rostrally as far as L5/L6. 3. Cells with unmyelinated axons recorded intrasomally were found to supply either low-threshold or high-threshold mechanoreceptors. Unlike A-delta-cells, all these cells had broad spikes with shoulders on the downstroke. Proportionally fewer C-fibers than A-delta-fibers projected as far as one segment rostral from their root entry zone. Of those that did, axons supplying low-threshold mechanoreceptors projected only in DC, whereas those innervating high-threshold mechanoreceptors could project either through LT or DC. 4. A-delta-fibers supplying LTMs and HTMRs exhibited a similar reduced conduction velocity was reduced even further in the spinal cord but much more for HTMRs than for LTMs. For C-fibers the conduction velocity decrease was more substantial in the dorsal root for HTMRs than for LTMs. 5. These findings suggest that axons innervating different peripheral receptors exhibit characteristic cellular properties. They confirm that the primary afferent component of Lissauer's Tract is specialized as a “pain pathway” but also indicate that the dorsal columns may play some role in the transmission of nociceptive information.

Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion Pain

2019 ◽  
pp. 71-78
Author(s):  
Daniel R. Cleary ◽  
Sharona Ben-Haim
Keyword(s):  
Brachial Plexus ◽  
Dorsal Horn ◽  
Dorsal Root ◽  
High Speed ◽  
Csf Leak ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Brachial Plexus Avulsion ◽  
Root Entry Zone ◽  
Dorsal Columns

Brachial plexus avulsion is often seen after motorcycle accidents or with high-speed ejection injuries. Rehabilitation focuses on regaining motor and sensory function, but the detrimental effect of pain is often underappreciated. Up to 90% of patients with avulsion injury will experience deafferentation pain, which until relatively recently has been difficult to treat medically or surgically. DREZotomy, the ablation of neurons in the dorsal root entry zone of the spinal cord, was introduced in the 1970s and has since changed how we treat brachial plexus avulsion and other forms of neuropathic pain. The procedure is straightforward: with a standard cervical approach, a hemilamiotomy is used to expose the area of interest. The dura is opened, and areas of root avulsion are identified. Using bipolar cautery, RF ablation, or ultrasound, the 2nd order neurons in dorsal horn are destroyed for the affected dermatomes. Complications include standard cervical spinal approach-related issues, such as infection, hematoma, CSF leak, and kyphosis. Risks specific to the procedure include post-operative motor or sensory deficits, due to the proximity of the corticospinal tracts and the dorsal columns to dorsal horn. As many as 18% of patients report a long-term neurological deficit post-operatively, but despite these complications, 80% of patients say they would repeat the procedure. Multiple outcomes series have been published since the procedure was introduced, and typically 70–80% of patients receive benefit from the procedure.

Behavior of upper cervical inspiratory propriospinal neurons during fictive vomiting

1991 ◽  
Vol 65 (6) ◽  
pp. 1492-1500 ◽  
Author(s):  
S. Nonaka ◽  
A. D. Miller
Keyword(s):  
Firing Pattern ◽  
Impulse Activity ◽  
Abdominal Muscle ◽  
Lateral Funiculus ◽  
Upper Cervical ◽  
Spinal Segments ◽  
Propriospinal Neurons ◽  
Lumbar Cord ◽  
Stimulation Of

1. The role of upper cervical inspiratory (UCI)-modulated neurons in respiratory muscle control during vomiting was examined by recording the impulse activity of these neurons during fictive vomiting in decerebrate, paralyzed cats. Fictive vomiting was identified by a characteristic series of bursts of coactivation of phrenic and abdominal muscle nerves, elicited either by electrical stimulation of supradiaphragmatic vagal nerve afferents or by emetic drugs, which would be expected to produce expulsion of gastric contents in nonparalyzed animals. 2. Data were recorded from 43 propriospinal UCI neurons, located in the C1-C3 spinal segments near the border of the intermediate gray matter and lateral funiculus, which were antidromically activated with floating pin electrodes placed in the ipsilateral lateral funiculus, usually at T1-T3. Some cells (9/21 tested) were also activated from the upper lumbar cord (L1). During respiration, most neurons (n = 40) had an augmenting discharge pattern during inspiration. In addition, more than one-half (55%) fired tonically during the remainder of the respiratory cycle. About 40% of UCI neurons showed variations in their firing pattern during the noninspiratory portion of respiration. These latter two properties of UCI neurons were not observed in dorsal and ventral respiratory group (DRG and VRG-, respectively) bulbospinal inspiratory (I) neurons previously recorded under similar conditions. 3. During fictive vomiting, the firing pattern of most UCI neurons fell into one of three main categories. More than one-half (53%) were active in phase with bursts of phrenic discharge and were thus classified as Active-type cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of Postoperative Magnetic Resonance Imaging after Microvascular Decompression of the Facial Nerve for the Treatment of Hemifacial Spasm

Neurosurgery ◽  
2002 ◽  
Vol 50 (4) ◽  
pp. 720-726 ◽  
Author(s):  
Jin Woo Chang ◽  
Jong Hee Chang ◽  
Jae Young Choi ◽  
Dong Ik Kim ◽  
Yong Gou Park ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Facial Nerve ◽  
Hemifacial Spasm ◽  
Short Range ◽  
Three Dimensional ◽  
Resonance Imaging ◽  
Entry Zone ◽  
Root Entry Zone

Abstract OBJECTIVE: This study was performed to investigate the role of postoperative three-dimensional short-range magnetic resonance angiography in the prediction of clinical outcomes after microvascular decompression (MVD) for the treatment of hemifacial spasm. METHODS: We examined pre- and postoperative magnetic resonance imaging scans obtained between March 1999 and May 2000 for 122 patients with hemifacial spasm, to evaluate the degree of detachment of the vascular contact and changes in the positions of offending vessels. The degree of vascular decompression of the facial nerve root was classified into three groups, i.e., contact, partial decompression, or complete decompression. Contact was defined as unresolved compression, as indicated by postoperative three-dimensional short-range magnetic resonance angiography. Partial decompression was defined as incompletely resolved compression; vascular indentation of the facial nerve was improved, but contact with the facial nerve remained. Complete decompression was defined as completely resolved compression. These findings were compared with the surgical findings and clinical outcomes. RESULTS: Of 122 patients with MVD, complete decompression of offending vessels at the root entry zone of the facial nerve was observed for 106 patients (86.9%), partial decompression was observed for 10 patients (8.2%), and contact with offending vessels was observed for 6 patients (4.9%) by using postoperative three-dimensional short-range magnetic resonance angiography. Our study demonstrated that the types of offending vessels affected neither the degree of decompression of the root entry zone of the facial nerve nor surgical outcomes (P > 0.05). Also, there was no significant relationship between the degree of decompression and improvement of symptoms (P > 0.05). Furthermore, there was no significant relationship between the degree of decompression and the timing of symptomatic improvement (P > 0.05). CONCLUSION: Our data suggest that MVD of the facial nerve alone may not be sufficient to resolve symptoms for all patients with hemifacial spasm. Therefore, unknown factors in addition to vascular compression may cause symptoms in certain cases, and it may be necessary to remove those factors, simultaneously with MVD, to obtain symptom resolution.

Microsurgery of Arnold-Chiari malformation in adults with and without hydromyelia

1976 ◽  
Vol 45 (5) ◽  
pp. 473-483 ◽  
Author(s):  
Albert L. Rhoton
Keyword(s):  
Chiari Malformation ◽  
Foramen Magnum ◽  
Intramedullary Tumor ◽  
Entry Zone ◽  
Content Type ◽  
Arnold Chiari Malformation ◽  
Suboccipital Craniectomy ◽  
Root Entry Zone ◽  
Upper Cervical ◽  
Bulbar Dysfunction

✓ Microsurgical exploration of 15 adults with Arnold-Chiari malformation with and without hydromyelia using 3 to 20 × magnification has led to the following conclusions. Hydromyelia, associated with Arnold-Chiari malformation, is a progressive mechanical disorder that causes spinal cord deficits by pressure distention of the cord. Arnold-Chiari malformation causes slowly or suddenly progressive bulbar dysfunction by impaction of the malformation in the foramen magnum. Decompression of both can be achieved by a suboccipital craniectomy, upper cervical laminectomy, establishing an outlet from the fourth ventricle, and opening the distended cord in the thinnest exposed area, which is usually along the dorsal root entry zone. If Pantopaque myelography in patients in the supine position shows the Arnold-Chiari malformation, hydromyelia can be established as a cause of central cord deficit even if myelography shows the cord size to be normal. Syringomyelia, traditionally considered a degenerative disease, is a less common cause of a slowly progressive central cord deficit than either hydromyelia or intramedullary tumor.

The Eustachian Tube as a Landmark for Early Identification of the Abducens Nerve During Endonasal Transclival Approaches

2018 ◽  
Vol 16 (6) ◽  
pp. 743-749 ◽  
Author(s):  
Juan M Revuelta Barbero ◽  
Somasundaram Subramaniam ◽  
Raywat Noiphithak ◽  
Juan C Yanez-Siller ◽  
Bradley A Otto ◽  
...  
Keyword(s):  
Eustachian Tube ◽  
Abducens Nerve ◽  
Horizontal Projection ◽  
Entry Zone ◽  
Root Entry Zone ◽  
Vertical Distance ◽  
Fresh Frozen ◽  
The Mean ◽  
Projection Point

Abstract BACKGROUND Expanded endonasal approaches have the potential to injure the abducens nerve (cranial nerve [CN] VI). The nerve's root entry zone (REZ) and cisternal segment (CS) are particularly prone to injury during the clivus resection and dural incision of transclival approaches. OBJECTIVE To investigate the role of the eustachian tube (ET) as a surgical landmark for the REZ and CS of CN VI. METHODS Transclival expanded endonasal approaches were performed bilaterally in 6 fresh-frozen cadaveric specimens (12 sides). Anatomic relationships between ET and CN VI were documented with neuronavigation. RESULTS The mean vertical distance from the inferior brainstem point to the horizontal projection of CN VI REZ, CS midpoint, and interdural segment (ID) were 26.38 mm (95% confidence interval [CI] 17.36-35.4), 38.61 mm (95% CI 25.61-51.61), and 42.68 mm (95% CI 30.14-55.22), respectively. The relative vertical distance from the ET to the horizontal projections of the REZ, CS midpoint, and its ID were 6.43 mm (95% CI 3.25-9.61), 18.66 mm (95% CI 11.52-25.8), and 22.72 mm (95% CI 16.02-29.42), respectively. In the axial plane the angles between the ET and (1) the REZ and its midline horizontal projection point, (2) the midpoint and its midline horizontal projection point, and (3) ID and its midline horizontal projection point were 9.81 ± SD 5.20°, 18.50 ± SD 4.87°, and 24.71 ± SD 6.21°, respectively. CONCLUSION The ET may serve as a constant landmark to reliably predict the position of the REZ and CS of CN VI.

scholarly journals Neuropeptides and the Nodes of Ranvier in Cranial Headaches

2022 ◽  
Vol 12 ◽  
Author(s):  
Jacob C. A. Edvinsson ◽  
Kristian A. Haanes ◽  
Lars Edvinsson
Keyword(s):  
Trigeminovascular System ◽  
Satellite Glial Cells ◽  
Entry Zone ◽  
Root Entry Zone ◽  
C Fibers ◽  
Calcitonin Gene ◽  
The Central Nervous System ◽  
Sensory Fibers ◽  
Different Parts

The trigeminovascular system (TGV) comprise of the trigeminal ganglion with neurons and satellite glial cells, with sensory unmyelinated C-fibers and myelinated Aδ-fibers picking up information from different parts of the head and sending signals to the brainstem and the central nervous system. In this review we discuss aspects of signaling at the distal parts of the sensory fibers, the extrasynaptic signaling between C-fibers and Aδ-fibers, and the contact between the trigeminal fibers at the nerve root entry zone where they transit into the CNS. We also address the possible role of the neuropeptides calcitonin gene-related peptide (CGRP), the neurokinin family and pituitary adenylyl cyclase-activating polypeptide 38 (PACAP-38), all found in the TGV system together with their respective receptors. Elucidation of the expression and localization of neuropeptides and their receptors in the TGV system may provide novel ways to understand their roles in migraine pathophysiology and suggest novel ways for treatment of migraine patients.

scholarly journals Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion: A Comprehensive Literature Review

2021 ◽  
Author(s):  
Axumawi Mike Hailu Gebreyohanes ◽  
Aminul Islam Ahmed ◽  
David Choi
Keyword(s):  
Brachial Plexus ◽  
Patient Outcomes ◽  
Dorsal Root ◽  
Cervical Spinal Cord ◽  
Entry Zone ◽  
Neurosurgical Procedure ◽  
Dorsal Root Entry Zone ◽  
Brachial Plexus Avulsion ◽  
Root Entry Zone ◽  
Comprehensive Literature Review

Abstract Dorsal root entry zone (DREZ) lesioning is a neurosurgical procedure that aims to relieve severe neuropathic pain in patients with brachial plexus avulsion by selectively destroying nociceptive neural structures in the posterior cervical spinal cord. Since the introduction of the procedure over 4 decades ago, the DREZ lesioning technique has undergone numerous modifications, with a variety of center- and surgeon-dependent technical differences and patient outcomes. We have reviewed the literature to discuss reported methods of DREZ lesioning and outcomes.

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