scholarly journals Punctate Midline Myelotomy Reduces Pain Responses in a Rat Model of Lumbar Spine Pain: Evidence that the Postsynaptic Dorsal Column Pathway Conveys Pain from the Axial Spine

Cureus ◽  
2018 ◽  
Author(s):  
Haring J Nauta ◽  
Sabrina L McIlwrath ◽  
Karin N Westlund
Keyword(s):  
Lumbar Spine ◽  
Rat Model ◽  
Dorsal Column ◽  
Spine Pain ◽  
Postsynaptic Dorsal Column ◽  
Pain Responses

Postsynaptic Dorsal Column and Cuneate Correlations in the Raccoon: A Re-evaluation by Parallel-Cascade Analysis

2002 ◽  
Vol 88 (6) ◽  
pp. 3372-3376
Author(s):  
Andrew S. French ◽  
Susan H. Dick ◽  
Douglas D. Rasmusson
Keyword(s):  
Cross Correlation ◽  
Volterra Series ◽  
Receptive Fields ◽  
Dorsal Column ◽  
Second Order ◽  
Input Signals ◽  
Cascade Analysis ◽  
Postsynaptic Dorsal Column ◽  
Positive Correlations ◽  
Cascade Method

In a previous study, we reported evidence for correlations between the firing of postsynaptic dorsal column (PSDC) neurons and cuneate neurons with overlapping receptive fields on the glabrous skin of the raccoon forepaw. The evidence was based on cross-correlation and frequency response analyses of spontaneously firing neurons. However, cross-correlation without white noise Gaussian analog inputs or Poisson distributed pulse train inputs is difficult to interpret because of the inherent convolution with the autocorrelation of the unknown input signals. While the data suggested positive correlations in the spinocuneate direction for most neuron pairs, we could not estimate the temporal characteristics of these putative connections. We have now re-analyzed these data using a parallel-cascade method to estimate the first- and second-order kernels of a Volterra series approximation to the spinocuneate system. This unbiased analysis suggests that a positive correlation occurs after about 5 ms, probably followed by a negative correlation at about 12 ms. Second-order kernels also had repeatable structure, indicating dual pathways with time separations of at least 10 ms.

Pelvic visceral input into the nucleus gracilis is largely mediated by the postsynaptic dorsal column pathway

1996 ◽  
Vol 76 (4) ◽  
pp. 2675-2690 ◽  
Author(s):  
E. D. Al-Chaer ◽  
N. B. Lawand ◽  
K. N. Westlund ◽  
W. D. Willis
Keyword(s):  
Intravenous Injection ◽  
Visceral Pain ◽  
Background Activity ◽  
Dorsal Column ◽  
Mustard Oil ◽  
Medial Lemniscus ◽  
Afferent Pathways ◽  
Nucleus Gracilis ◽  
Before And After ◽  
Postsynaptic Dorsal Column

1. The purpose of this study was to investigate a proposed role for the postsynaptic dorsal column (PSDC) pathway in mediating visceral nociceptive input into the dorsal column (DC) nuclei. 2. In one group of animals, the hypogastric nerves were sectioned, thereby restricting colorectal input into the cord to pelvic afferent pathways known to coverage on lower lumbar and sacral segments. Extracellular recording were made from 41 nucleus gracilis (NG) cells that responded to colorectal distension (CRD). Results reported are from 15 NG cells that were tested before and after the administration of morphine into the sacral cord by microdialysis. 3. The responses of 11 NG cells to CRD were dramatically reduced by morphine infused into the sacral cord through a microdialysis fiber. This reduction was reversed by an intravenous injection of naloxone. Microdialysis administration of 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX) or a lesion of the DC also abolished the responses of the NG cells to CRD. 4. Four NG cells that responded to CRD showed an increase in their background activity approximately 25 min after an injection of mustard oil (MO). This increase in activity was counteracted by morphine or by a lesion of the DC. 5. In a second group of animals, recordings were made from 28 PSDC cells in the L0-S1 segments of the cord. These units were antidromically activated by stimulation of the upper cervical fasciculus gracilis. The projections of five PSDC neurons into the NG were traced with the use of antidromic mapping. Results are reported for the responses of 12 PSDC cells to CRD and to cutaneous stimuli before and after morphine administration into the sacral cord by microdialysis. 6. Morphine given spinally reduced the responses of 12 PSDC cells to CRD. This reduction was reversed by an intravenous injection of naloxone. CNQX administered spinally also abolished the responses to CRD of the PSDC cells tested. 7. Four other PSDC cells were studied before and after an injection of MO into the colon. Their background activity started to increase within 25 min after the injection. Morphine suppressed this increase in background activity and this effect of morphine was reversed by naloxone. 8. The responses of NG cells to cutaneous stimuli were not significantly affected by morphine in the dose used. On the other hand, morphine significantly reduced the responses of PSDC cells to noxious cutaneous stimuli although this effect was not as dramatic as that on responses to visceral stimuli. 9. From the results of the studies described in this and the companion paper, we conclude that there is an important pelvic visceral nociceptive pathway involving PSDC neurons that synapse in the NG. The NG in turn activates neurons in the ventral posterolateral (VPL) nucleus of the thalamus. We presume that activation of VPL neurons by noxious visceral stimulation contributes to visceral pain sensation and thus that pelvic visceral pain depends largely on activity in the DC-medial lemniscus system.

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