Antinocioceptive Effects of Spinal Cord Stimulation by Activation of Periaqueductal Gray Matter and Rostral Ventromedial Medulla: A Mechanism Beyond the Gate Control Theory

2018 ◽  
Vol 21 (5) ◽  
pp. 520-521 ◽  
Author(s):  
Mousa Taghipour ◽  
Fariborz Ghaffarpasand
Keyword(s):  
Spinal Cord ◽  
Control Theory ◽  
Gray Matter ◽  
Spinal Cord Stimulation ◽  
Periaqueductal Gray ◽  
Rostral Ventromedial Medulla ◽  
Periaqueductal Gray Matter ◽  
Gate Control Theory ◽  
Ventromedial Medulla ◽  
Gate Control

Spinal cord stimulation

2010 ◽  
pp. 161-169
Author(s):  
Brian A. Simpson
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Control Theory ◽  
Spinal Cord Stimulation ◽  
Gate Control Theory ◽  
Relieve Pain ◽  
Gate Control ◽  
The 1960S

Electricity has been used for centuries to relieve pain but spinal cord stimulation (SCS) came about with the Gate Control Theory in the 1960s SCS was originally thought simply to close the gate by activating A fibres but its effect is more complex. It is likely that it helps to normalize the dysfunction that manifests as neuropathic pain...

scholarly journals Spinal sensory projection neuron responses to spinal cord stimulation are mediated by circuits beyond gate control

2015 ◽  
Vol 114 (1) ◽  
pp. 284-300 ◽  
Author(s):  
Tianhe C. Zhang ◽  
John J. Janik ◽  
Ryan V. Peters ◽  
Gang Chen ◽  
Ru-Rong Ji ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Control Theory ◽  
Spinal Cord Stimulation ◽  
Projection Neuron ◽  
Control Circuit ◽  
Neuron Activity ◽  
Projection Neurons ◽  
Intractable Pain ◽  
Gate Control Theory ◽  
Gate Control

Spinal cord stimulation (SCS) is a therapy used to treat intractable pain with a putative mechanism of action based on the Gate Control Theory. We hypothesized that sensory projection neuron responses to SCS would follow a single stereotyped response curve as a function of SCS frequency, as predicted by the Gate Control circuit. We recorded the responses of antidromically identified sensory projection neurons in the lumbar spinal cord during 1- to 150-Hz SCS in both healthy rats and neuropathic rats following chronic constriction injury (CCI). The relationship between SCS frequency and projection neuron activity predicted by the Gate Control circuit accounted for a subset of neuronal responses to SCS but could not account for the full range of observed responses. Heterogeneous responses were classifiable into three additional groups and were reproduced using computational models of spinal microcircuits representing other interactions between nociceptive and nonnociceptive sensory inputs. Intrathecal administration of bicuculline, a GABAA receptor antagonist, increased spontaneous and evoked activity in projection neurons, enhanced excitatory responses to SCS, and reduced inhibitory responses to SCS, suggesting that GABAA neurotransmission plays a broad role in regulating projection neuron activity. These in vivo and computational results challenge the Gate Control Theory as the only mechanism underlying SCS and refine our understanding of the effects of SCS on spinal sensory neurons within the framework of contemporary understanding of dorsal horn circuitry.

Repeated spinal cord stimulation decreases the extracellular level of γ-aminobutyric acid in the periaqueductal gray matter of freely moving rats

1995 ◽  
Vol 699 (2) ◽  
pp. 231-241 ◽  
Author(s):  
Carl-Olav Stiller ◽  
Bengt Linderoth ◽  
William T. O'Connor ◽  
Johan Franck ◽  
Torkel Falkenberg ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Gray Matter ◽  
Spinal Cord Stimulation ◽  
Periaqueductal Gray ◽  
Aminobutyric Acid ◽  
Periaqueductal Gray Matter ◽  
Freely Moving Rats ◽  
Extracellular Level ◽  
Freely Moving

Dorsal horn projection targets of ON and OFF cells in the rostral ventromedial medulla

1995 ◽  
Vol 74 (4) ◽  
pp. 1742-1759 ◽  
Author(s):  
H. L. Fields ◽  
A. Malick ◽  
R. Burstein
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Gray Matter ◽  
Cervical Spinal Cord ◽  
Rostral Ventromedial Medulla ◽  
Minimum Threshold ◽  
Antidromic Activation ◽  
Spinal Cord Neurons ◽  
Ventromedial Medulla ◽  
On And Off Cells

1. The rostral ventromedial medulla (RVM) participates in the modulation of nociceptive transmission by spinal cord neurons. Previous anatomic studies have demonstrated that RVM neurons project to laminae I, II, and V of the dorsal horn; laminae VII and VIII of the intermediate and ventral horns; the intermediolateral column; and lamina X. The RVM contains at least three physiologically defined classes of neurons, two of which, the ON and the OFF cells, have been implicated in nociceptive modulation. Because these cells classes are intermingled in the RVM, it has not been possible to determine the spinal laminar projection targets of ON and OFF cells by anatomic methods. Therefore in the current study we employed antidromic microstimulation methods to determine the laminar projections of two of the three classes of RVM neurons, the ON and the OFF cells. 2. In lightly anesthetized (with methohexital sodium) rats, single-unit extracellular recordings were made from 48 RVM neurons that were physiologically characterized as ON (30) or OFF (18) cells. The recording locations of 45 of these neurons were recovered. Thirty-seven were found in the nucleus raphe magnus and eight were located near its dorsal and lateral borders. 3. Thirty-two physiologically identified RVM neurons (18 ON and 14 OFF cells) were antidromically activated from the cervical spinal cord using a monopolar stimulating electrode. The stimulating electrode was moved systematically in the white matter until antidromic activation could be produced with currents of < or = 20 microA (6.1 +/- 0.7 microA, mean +/- SE). The points from which minimum currents were required to antidromically activate the neurons were located mainly in the ipsilateral dorsolateral funiculus (DLF) (27 of 32). In a few cases, lowest antidromic threshold currents were found near the border between the DLF and ventrolateral funiculus (VLF) or, rarely, in the VLF itself. In these cases, the cell recordings were found to be near the dorsal boundary of the RVM. 4. While one electrode was used to stimulate the parent axon in the lateral funiculus, a second was used to explore the gray matter for the presence of collateral branches. The identification of a branch was initially determined by an increase in antidromic latency. At the same rostrocaudal plane of the spinal cord, stimulation of the DLF induced an antidromic spike that invaded the neuron earlier than the antidromic spike elicited by stimulation in the gray matter. Collateral branches were confirmed by establishing that the location of the minimum threshold point for antidromic activation of the neurons from the second electrode was in the gray matter, that the minimum current required to antidromically activate the neuron from that point was too low to activate the parent axon in the DLF, and that a collision occurred between the spikes induced by the two stimulating electrodes. 5. In 17 cases, physiologically identified RVM neurons (10 ON and 7 OFF cells) were antidromically activated from the gray matter of the cervical spinal cord using a current of 8.4 +/- 2.1 (SE) microA. Minimum threshold points for antidromic activation were found in laminae I-II (3 ON and 4 OFF cells), lamina V (5 ON and 6 OFF cells), and regions ventral to the lateral reticulated area (3 ON and 2 OFF cells) of the gray matter. As indicated by these numbers, some neurons were antidromically activated from more than one gray matter region. In general, all OFF cells and 9 of 10 ON cells were antidromically activated from low threshold points in either laminae I-II or lamina V. 6. In six cases, neurons were activated from separate points located in two or three different laminae of the gray matter. Three OFF cells were activated from laminae I-II and V, one OFF cell and one ON cell were activated from lamina V and from more ventral points, and one ON cell was activated from laminae I-II and from points ventral to lamina V.

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