The encoding of the thermal grill illusion in the human spinal cord

Abstract Aims The spatial alternation of innocuous cold and warm stimuli on the skin can paradoxically provoke a hot, burning sensation, known as the thermal-grill illusion (TGI). Whether the TGI depends on spinal or supraspinal integration mechanisms is still debated. To assess whether the TGI can be accounted by integration of cold and warm afferent signals in the spinal cord, we leveraged anatomical knowledge on the spatial arrangement of dermatomes and spinal segmental projections. Methods We stimulated a series of skin locations on the right arm using one cold (∼20 °C) and one warm thermode (∼40°C). The two stimulus locations had identical physical distance on the skin. However, the distance between the cold and heat projection signals in the spinal cord varied across three conditions. Cold and warm inputs were delivered (1) within the same dermatome (e.g., C5–C5); (2) across the dermatome boundary of two adjacent spinal segments (e.g., C5–C6); (3) across the dermatome boundary of two non-adjacent spinal segments (e.g., C5–T1). In two experiments, we obtained an estimate of the strength of the TGI by asking 32 healthy participants to complete a temperature matching task. Results Participants overestimated the actual average temperature of the two thermodes (Exp. 1) and the cold temperature of one of the two thermodes (Exp. 2). However, this effect was significantly larger when cold and heat stimuli were delivered within the same dermatome (+6.57 ± 3.99°C and +9.88 ± 5.60 °C) or between dermatomes projecting to adjacent spinal segments (+6.26 ±4.44°C and +9.48 ± 5.83 °C), compared to when cold and heat stimuli projected to non-adjacent spinal segments (+3.46 ± 4.46 °C and +4.80 ± 3.21 °C). Conclusions These results demonstrate that the strength of the illusion is modulated by the segmental distance between cold and heat spinal signals, and show that the perceived quality and intensity of thermal stimuli depends upon low-level spatial summation mechanisms in the spinal cord.

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Spinal Cord Maps of Spatiotemporal Alpha-Motoneuron Activation in Humans Walking at Different Speeds

Journal of Neurophysiology ◽

10.1152/jn.00767.2005 ◽

2006 ◽

Vol 95 (2) ◽

pp. 602-618 ◽

Cited By ~ 107

Author(s):

Y. P. Ivanenko ◽

R. E. Poppele ◽

F. Lacquaniti

Keyword(s):

Spinal Cord ◽

Center Of Mass ◽

Trunk Muscles ◽

Emg Activity ◽

Step Cycle ◽

Human Spinal Cord ◽

Spinal Segments ◽

Motoneuron Activity ◽

Pattern Generators ◽

Walking Speeds

Functional MRI (fMRI) imaging of motoneuron activity in the human spinal cord is still in its infancy, and it will remain difficult to apply to walking. Here we present a viable alternative for documenting the spatiotemporal maps of α-motorneuron (MN) activity in the human spinal cord during walking, similar to the method recently reported for the cat. We recorded EMG activity from 16 to 32 ipsilateral limb and trunk muscles in 13 healthy subjects walking on a treadmill at different speeds (1–7 km/h) and mapped the recorded patterns onto the spinal cord in approximate rostrocaudal locations of the motoneuron pools. This approach can provide information about pattern generator output during locomotion in terms of segmental control rather than in terms of individual muscle control. A striking feature we found is that nearly every spinal segment undergoes at least two cycles of activation in the step cycle, thus supporting the idea of half-center oscillators controlling MN activation at any segmental level. The resulting spatiotemporal map patterns seem highly stereotyped over the range of walking speeds studied, although there were also some systematic redistributions of MN activity with speed. Bursts of MN activity were either temporally aligned across several spinal segments or switched between different segments. For example, the center of mass of MN activity in the lumbosacral levels generally shifted from rostral to caudal positions in two cycles for each step, revealing four major activation foci: two in the upper lumbar segments and two in the sacral segments. The results are consistent with the presence of at least two and possibly more pattern generators controlling the activation of lumbosacral MNs.

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Crossed Commissural Pathways in the Spinal Hindlimb Enlargement Are Not Necessary for Right–Left Hindlimb Alternation During Turtle Swimming

Journal of Neurophysiology ◽

10.1152/jn.00722.2007 ◽

2007 ◽

Vol 98 (4) ◽

pp. 2223-2231 ◽

Cited By ~ 12

Author(s):

Ramsey F. Samara ◽

Scott N. Currie

Keyword(s):

Spinal Cord ◽

Commissural Axons ◽

Commissural Pathways ◽

Before And After ◽

Spinal Segments ◽

Hindlimb Movement ◽

Phase Coordination ◽

The Right ◽

Hip Flexor

We examined the coordination between right and left hindlimbs during voluntary forward swimming in adult red-eared turtles, before and after midsagittal section of the spinal cord hindlimb enlargement (segments D8–S2) or the enlargement plus the first preenlargement segment (D7–S2). Our purpose was to assess the role of crossed commissural axons in these segments for right–left hindlimb alternation during voluntary locomotion. Midsagittal splitting severed commissural fibers and separated the right and left halves of the posterior spinal cord. Adult turtles ( n = 9) were held by a band clamp around the shell in a water-filled tank while digital video of forward swimming was recorded from below and computer analyzed with motion analysis software. In a subset of these animals ( n = 5), we also recorded electromyograms from hip extensor and/or hip flexor muscles on both sides. Surprisingly, splitting spinal segments D8–S2 or D7–S2 did not affect the strength of out-of-phase coordination between right and left hindlimbs, although hindlimb movement amplitudes were reduced compared with presurgical controls. These results show that commissural axons in the hindlimb enlargement and preenlargement cord are not necessary for right–left hindlimb alternation during voluntary swimming. We suggest that alternating propriospinal drive from the right and left sides of the forelimb enlargement maintains the out-of-phase coordination of right and left hindlimbs in the bisected-cord preparation. Our data support the hypothesis that descending propriospinal (forelimb–hindlimb) and crossed commissural (hindlimb–hindlimb) spinal cord pathways function together as redundant mechanisms to sustain right–left hindlimb alternation during turtle locomotion.

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CASE REPORT: SURGICAL MANAGEMENT OF LUMBAR COMPRESSION FRACTURE

Neurologico Spinale Medico Chirurgico ◽

10.15562/nsmc.v1i4.131 ◽

2019 ◽

Vol 1 (4) ◽

Author(s):

Yustinus Robby Budiman Gondowardojo ◽

Tjokorda Gde Bagus Mahadewa

Keyword(s):

Spinal Cord ◽

Left Lung ◽

Lumbar Vertebrae ◽

Compression Fracture ◽

High Mobility ◽

Early Mobilization ◽

Cord Injury ◽

Cardiothoracic Surgeon ◽

The Right

The lumbar vertebrae are the most common site for fracture incident because of its high mobility. The spinal cord injury usually happened as a result of a direct traumatic blow to the spine causing fractured and compressed spinal cord. A 38-year-old man presented with lumbar spine’s compression fracture at L2 level. In this patient, decompression laminectomy, stabilization, and fusion were done by posterior approach. The operation was successful, according to the X-Ray and patient’s early mobilization. Pneumothorax of the right lung and pleural effusion of the left lung occurred in this patient, so consultation was made to a cardiothoracic surgeon. Chest tube and WSD insertion were performed to treat the comorbidities. Although the patient had multiple trauma that threat a patient’s life, the management was done quickly, so the problems could be solved thus saving the patient’s life. After two months follow up, the patient could already walk and do daily activities independently.

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Effects of Haematopoietic Autologous Stem Cell Transplantation To The Chronically Injured Human Spinal Cord Evaluated By Motor and Somatosensory Evoked Potentials Methods

Cell Transplantation ◽

10.3727/096368911x633761 ◽

2012 ◽

Author(s):

A., A. Frolov ◽

A., S. Bryukhovetskiy

Keyword(s):

Spinal Cord ◽

Stem Cell ◽

Stem Cell Transplantation ◽

Evoked Potentials ◽

Cell Transplantation ◽

Autologous Stem Cell Transplantation ◽

Somatosensory Evoked Potentials ◽

Human Spinal Cord

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Hypogastric Artery Stenting for Chronic Intermittent Spinal Cord Ischemia After Thoracic Endovascular Aortic Repair

Journal of Endovascular Therapy ◽

10.1177/1526602820925445 ◽

2020 ◽

Vol 27 (5) ◽

pp. 801-804

Author(s):

Catharina Gronert ◽

Nikolaos Tsilimparis ◽

Giuseppe Panuccio ◽

Ahmed Eleshra ◽

Fiona Rohlffs ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Ischemia ◽

Thoracic Endovascular Aortic Repair ◽

Neurological Symptoms ◽

Endovascular Aortic Repair ◽

Hypogastric Artery ◽

Lower Extremity Weakness ◽

Aortic Repair ◽

The Right

Purpose: To report a case of chronic intermittent spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) and its successful treatment using hypogastric artery stenting. Case Report: A 79-year-old patient presented in May 2013 with a thoracic aortic aneurysm (TAA) and a contained rupture. He urgently underwent TEVAR that covered 274 mm of descending thoracic aorta without immediate postoperative signs of acute SCI. At 3-month follow-up, he reported repeating incidents of sudden lower extremity weakness leading to a fall with a humerus fracture. A neurological consultation revealed the tentative diagnosis of intermittent SCI caused by TEVAR and initially recommended a conservative approach. During the following year there was no clinical improvement of the symptoms. Computed tomography angiography showed a high-grade stenosis of the right hypogastric artery, which was stented in November 2014 to improve the collateral network of spinal cord perfusion. Following treatment, the patient had no further neurological symptoms; at 32 months after the reintervention, the imaging follow-up documented a patent stent and continued exclusion of the TAA. Conclusion: Intermittent neurological symptoms after TEVAR should be suspected as chronic intermittent SCI. The improvement of collateral networks of the spinal cord by revascularization of the hypogastric artery is a viable treatment option.

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Commissural Interneurons in Rhythm Generation and Intersegmental Coupling in the Lamprey Spinal Cord

Journal of Neurophysiology ◽

10.1152/jn.1999.81.5.2037 ◽

1999 ◽

Vol 81 (5) ◽

pp. 2037-2045 ◽

Cited By ~ 44

Author(s):

James T. Buchanan

Keyword(s):

Spinal Cord ◽

Amino Acid ◽

Excitatory Amino Acid ◽

Rhythmic Activity ◽

Ventral Root ◽

Rhythm Generation ◽

Spinal Segment ◽

Spinal Segments ◽

Autocorrelation Method

Commissural interneurons in rhythm generation and intersegmental coupling in the lamprey spinal cord. To test the necessity of spinal commissural interneurons in the generation of the swim rhythm in lamprey, longitudinal midline cuts of the isolated spinal cord preparation were made. Fictive swimming was then induced by bath perfusion with an excitatory amino acid while recording ventral root activity. When the spinal cord preparation was cut completely along the midline into two lateral hemicords, the rhythmic activity of fictive swimming was lost, usually replaced with continuous ventral root spiking. The loss of the fictive swim rhythm was not due to nonspecific damage produced by the cut because rhythmic activity was present in split regions of spinal cord when the split region was still attached to intact cord. The quality of this persistent rhythmic activity, quantified with an autocorrelation method, declined with the distance of the split spinal segment from the remaining intact spinal cord. The deterioration of the rhythm was characterized by a lengthening of burst durations and a shortening of the interburst silent phases. This pattern of deterioration suggests a loss of rhythmic inhibitory inputs. The same pattern of rhythm deterioration was seen in preparations with the rostral end of the spinal cord cut compared with those with the caudal end cut. The results of this study indicate that commissural interneurons are necessary for the generation of the swimming rhythm in the lamprey spinal cord, and the characteristic loss of the silent interburst phases of the swimming rhythm is consistent with a loss of inhibitory commissural interneurons. The results also suggest that both descending and ascending commissural interneurons are important in the generation of the swimming rhythm. The swim rhythm that persists in the split cord while still attached to an intact portion of spinal cord is thus imposed by interneurons projecting from the intact region of cord into the split region. These projections are functionally short because rhythmic activity was lost within approximately five spinal segments from the intact region of spinal cord.

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