The Propriospinal System

Conta, Amanda C.; Stelzner, Dennis J.

doi:10.1016/b978-0-12-374247-6.50016-x

Cited by 18 publications

(24 citation statements)

References 100 publications

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“…Individual interneurons are known to traverse in ipsilateral as well as contralateral fashion, interacting with different regions of the spinal gray matter (12). These interneurons are associated with a diverse array of functions, including the modulation of various afferent and efferent signals (13). …”

Section: Discussionmentioning

confidence: 99%

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Intrinsic Resting-State Functional Connectivity in the Human Spinal Cord at 3.0 T

et al. 2016

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Purpose To apply resting-state functional magnetic resonance (MR) imaging to map functional connectivity of the human spinal cord. Materials and Methods Studies were performed in nine self-declared healthy volunteers with informed consent and institutional review board approval. Resting-state functional MR imaging was performed to map functional connectivity of the human cervical spinal cord from C1 to C4 at 1 × 1 × 3-mm resolution with a 3.0-T clinical MR imaging unit. Independent component analysis (ICA) was performed to derive resting-state functional MR imaging z-score maps rendered on two-dimensional and three-dimensional images. Seed-based analysis was performed for cross validation with ICA networks by using Pearson correlation. Results Reproducibility analysis of resting-state functional MR imaging maps from four repeated trials in a single participant yielded a mean z score of 6 ± 1 (P < .0001). The centroid coordinates across the four trials deviated by 2 in-plane voxels ± 2 mm (standard deviation) and up to one adjacent image section ± 3 mm. ICA of group resting-state functional MR imaging data revealed prominent functional connectivity patterns within the spinal cord gray matter. There were statistically significant (z score > 3, P < .001) bilateral, unilateral, and intersegmental correlations in the ventral horns, dorsal horns, and central spinal cord gray matter. Three-dimensional surface rendering provided visualization of these components along the length of the spinal cord. Seed-based analysis showed that many ICA components exhibited strong and significant (P < .05) correlations, corroborating the ICA results. Resting-state functional MR imaging connectivity networks are qualitatively consistent with known neuroanatomic and functional structures in the spinal cord. Conclusion Resting-state functional MR imaging of the human cervical spinal cord with a 3.0-T clinical MR imaging unit and standard MR imaging protocols and hardware reveals prominent functional connectivity patterns within the spinal cord gray matter, consistent with known functional and anatomic layouts of the spinal cord.

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Section: Discussionmentioning

confidence: 99%

“…The role of this “centromedullary” activity may be attributed to midline interneuronal synapses, which have been implicated in mediating autonomic signals (13–16). There may also be contributions from the medial aspect of the nearby ventral horns, which are involved in reflex and posture maintenance.…”

Section: Discussionmentioning

confidence: 99%

Intrinsic Resting-State Functional Connectivity in the Human Spinal Cord at 3.0 T

et al. 2016

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“…These neurons greatly outnumber the motor neurons in the spinal cord and mediate a variety of functions while integrating and modulating both sensory and motor inputs (Chung et al, 1984; Conta and Stelzner 2009; Flynn et al, 2011). While short-axon propriospinal neurons in the lumbar enlargement modulate input to lower limb motor neuron pools (Gerasimenko et al, 2002; Jordan and Schmidt, 2002; Kostyuk and Maisky, 1972; Kostyuk et al, 1971), ascending and descending long-axon propriospinal neurons can mediate the crosstalk between lumbosacral and cervical regions (Miller, 1970; Miller et al, 1971, 1973).…”

Section: Discussionmentioning

confidence: 99%

Exercise dependent increase in axon regeneration into peripheral nerve grafts by propriospinal but not sensory neurons after spinal cord injury is associated with modulation of regeneration-associated genes

Sachdeva

Theisen

Ninan

et al. 2016

Experimental Neurology

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Insufficient regeneration of central nervous system (CNS) axons contributes to persisting neurological dysfunction after spinal cord injury (SCI). Peripheral nerve grafts (PNGs) support regeneration by thousands of injured intraspinal axons and help them bypass some of the extracellular barriers that form after SCI. However this number represents but a small portion of the total number of axons that are injured. Here we tested if rhythmic sensory stimulation during cycling exercise would boost the intrinsic regenerative state of neurons to enhance axon regeneration into PNGs after a lower thoracic (T12) spinal transection of adult rats. Using True Blue retrograde tracing, we show that 4 weeks of cycling improves regeneration into a PNG from lumbar interneurons but not by primary sensory neurons. The majority of neurons that regenerate their axon are within 5mm of the lesion and their number increased 70% with exercise. Importantly propriospinal neurons in more distant regions (5–20 mm from the lesion) that routinely exhibit very limited regeneration responded to exercise by increasing the number of regenerating neurons by 900%. There was no exercise-associated increase in regeneration from sensory neurons. Analyses using fluorescent in situ hybridization showed that this increase in regenerative response is associated with changes in levels of mRNAs encoding the regeneration associated genes (RAGs) GAP43, β-actin and Neuritin. While propriospinal neurons showed increased mRNA levels in response to SCI alone and then to grafting and exercise, sensory neurons did not respond to SCI, but there was a response to the presence of a PNG. Thus, exercise is a non-invasive approach to modulate gene expression in injured neurons leading to an increase in regeneration. This sets the stage for future studies to test whether exercise will promote axon outgrowth beyond the PNG and reconnection with spinal cord neurons, thereby demonstrating a potential clinical application of this combined therapeutic intervention.

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“…The spinal cord's "own" projection system refers to neurons that are located in the spinal cord, whose axons interconnect various spinal cord levels [5]. This so-called propriospinal system constitutes a large part of the white matter.…”

Section: The Propriospinal Systemmentioning

confidence: 99%

“…The propriospinal neurons also modulate input to the lumbar central pattern generator (CPG), a local system involved in reflexive stepping in total absence of supraspinal input [5]. Serotonin from brainstem neurons has been shown to play a major role in CPG activation [6,7].…”

Section: The Propriospinal Systemmentioning

confidence: 99%

Experimental Spinal Cord Injury Models in Rodents: Anatomical Correlations and Assessment of Motor Recovery

Vogelaar¹,

Estrada²

2016

Recovery of Motor Function Following Spinal Cord Injury

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Human traumatic spinal cord injury (SCI) causes disruption of descending motor and ascending sensory tracts, which leads to severe disturbances in motor functions. To date, no standard therapy for the regeneration of severed spinal cord axons in humans exists. Experimental SCI in rodents is essential for the development of new treatment strategies and for understanding the underlying mechanisms leading to motor recovery. Here, we provide an overview of the main rodent models and techniques available for the investigation of neuronal regeneration and motor recovery after experimental SCI.

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The Propriospinal System

Cited by 18 publications

References 100 publications

Intrinsic Resting-State Functional Connectivity in the Human Spinal Cord at 3.0 T

Intrinsic Resting-State Functional Connectivity in the Human Spinal Cord at 3.0 T

Exercise dependent increase in axon regeneration into peripheral nerve grafts by propriospinal but not sensory neurons after spinal cord injury is associated with modulation of regeneration-associated genes

Experimental Spinal Cord Injury Models in Rodents: Anatomical Correlations and Assessment of Motor Recovery

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