Chapter 15 Intraoperative neurophysiology of the corticospinal tract of the spinal cord

2006 ◽  
pp. 107-112 ◽  
Author(s):  
Vedran Deletis
Keyword(s):  
Spinal Cord ◽  
Corticospinal Tract ◽  
Intraoperative Neurophysiology

A critical reappraisal of corticospinal tract somatotopy and its role in traumatic cervical spinal cord syndromes

2021 ◽  
pp. 1-7
Author(s):  
Allan D. Levi ◽  
Jan M. Schwab
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Upper Extremity ◽  
Corticospinal Tract ◽  
Cervical Spinal Cord ◽  
Hand Function ◽  
Cervical Spinal Cord Injury ◽  
Pathophysiological Mechanism ◽  
Cord Injury ◽  
Central Cord Syndrome

The corticospinal tract (CST) is the preeminent voluntary motor pathway that controls human movements. Consequently, long-standing interest has focused on CST location and function in order to understand both loss and recovery of neurological function after incomplete cervical spinal cord injury, such as traumatic central cord syndrome. The hallmark clinical finding is paresis of the hands and upper-extremity function with retention of lower-extremity movements, which has been attributed to injury and the sparing of specific CST fibers. In contrast to historical concepts that proposed somatotopic (laminar) CST organization, the current narrative summarizes the accumulated evidence that 1) there is no somatotopic organization of the corticospinal tract within the spinal cord in humans and 2) the CST is critically important for hand function. The evidence includes data from 1) tract-tracing studies of the central nervous system and in vivo MRI studies of both humans and nonhuman primates, 2) selective ablative studies of the CST in primates, 3) evolutionary assessments of the CST in mammals, and 4) neuropathological examinations of patients after incomplete cervical spinal cord injury involving the CST and prominent arm and hand dysfunction. Acute traumatic central cord syndrome is characterized by prominent upper-extremity dysfunction, which has been falsely predicated on pinpoint injury to an assumed CST layer that specifically innervates the hand muscles. Given the evidence surveyed herein, the pathophysiological mechanism is most likely related to diffuse injury to the CST that plays a critically important role in hand function.

scholarly journals Protection of corticospinal tract neurons after dorsal spinal cord transection and engraftment of olfactory ensheathing cells

Glia ◽  
2006 ◽  
Vol 53 (4) ◽  
pp. 352-359 ◽  
Author(s):  
Masanori Sasaki ◽  
Bryan C. Hains ◽  
Karen L. Lankford ◽  
Stephen G. Waxman ◽  
Jeffery D. Kocsis
Keyword(s):  
Spinal Cord ◽  
Corticospinal Tract ◽  
Spinal Cord Transection ◽  
Olfactory Ensheathing Cells ◽  
Dorsal Spinal Cord ◽  
Ensheathing Cells ◽  
Dorsal Spinal

Lack of adenylate cyclase 1 (AC1): Consequences on corticospinal tract development and on locomotor recovery after spinal cord injury

2014 ◽  
Vol 1549 ◽  
pp. 1-10 ◽  
Author(s):  
H. Nait Taleb Ali ◽  
M.P. Morel ◽  
M. Doulazmi ◽  
S. Scotto-Lomassese ◽  
P. Gaspar ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Adenylate Cyclase ◽  
Corticospinal Tract ◽  
Locomotor Recovery ◽  
Cord Injury

scholarly journals Segmental analysis in cervical spinal cord injury reveals the recovery potential of hand muscles with preserved corticospinal tract: Insights beyond impairment scales

2021 ◽  
Author(s):  
Gustavo Balbinot ◽  
Guijin Li ◽  
Sukhvinder Kalsi-Ryan ◽  
Rainer Abel ◽  
Doris Maier ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Muscle Strength ◽  
Evoked Potentials ◽  
Corticospinal Tract ◽  
Cervical Spinal Cord ◽  
Hand Muscles ◽  
Recovery Potential ◽  
Strength Recovery ◽  
Cord Injury

Cervical spinal cord injury (SCI) severely impacts widespread bodily functions with extensive impairments for individuals, who prioritize regaining hand function. Although prior work has focused on the recovery at the person-level, the factors determining the recovery potential of individual muscles are poorly understood. There is a need for changing this paradigm in the field by moving beyond person-level classification of residual strength and sacral sparing to a muscle-specific analysis with a focus on the role of corticospinal tract (CST) sparing. The most striking part of human evolution involved the development of dextrous hand use with a respective expansion of the sensorimotor cortex controlling hand movements, which, because of the extensive CST projections, may constitute a drawback after SCI. Here, we investigated the muscle-specific natural recovery after cervical SCI in 748 patients from the European Multicenter Study about SCI (EMSCI), one of the largest datasets analysed to date. All participants were assessed within the first 4 weeks after SCI and re-assessed at 12, 24, and 48 weeks. Subsets of individuals underwent electrophysiological multimodal evaluations to discern CST and lower motor neuron (LMN) integrity [motor evoked potentials (MEP): N = 203; somatosensory evoked potentials (SSEP): N = 313; nerve conduction studies (NCS): N = 280]. We show the first evidence of the importance of CST sparing for proportional recovery in SCI, which is known in stroke survivors to represent the biological limits of structural and functional plasticity. In AIS D, baseline strength is a good predictor of segmental muscle strength recovery, while the proportionality in relation to baseline strength is lower for AIS B/C and breaks for AIS A. More severely impaired individuals showed non-linear and more variable recovery profiles, especially for hand muscles, while measures of CST sparing (by means of MEP) improved the prediction of hand muscle strength recovery. Therefore, assessment strategies for muscle-specific motor recovery in acute SCI improve by accounting for CST sparing and complement gross person-level predictions. The latter is of paramount importance for clinical trial outcomes and to target neurorehabilitation of upper limb function, where any single muscle function impacts the outcome of independence in cervical SCI.

Direct projection of the corticospinal tract to the superficial laminae of the spinal cord in the rat

1988 ◽  
Vol 278 (2) ◽  
pp. 275-286 ◽  
Author(s):  
Eugene J. Casale ◽  
Alan R. Light ◽  
Aldo Rustioni
Keyword(s):  
Spinal Cord ◽  
Corticospinal Tract ◽  
Direct Projection

Spinal cord representation of motor cortex plasticity reflects corticospinal tract LTP

2021 ◽  
Vol 118 (52) ◽  
pp. e2113192118
Author(s):  
Alzahraa Amer ◽  
Jianxun Xia ◽  
Michael Smith ◽  
John H. Martin
Keyword(s):  
Spinal Cord ◽  
Motor Cortex ◽  
Corticospinal Tract ◽  
Cervical Spinal Cord ◽  
Long Term Potentiation ◽  
Dependent Manner ◽  
Term Potentiation ◽  
Spinal Cord Segment ◽  
Spinal Interneuron ◽  
Activity Dependent

Although it is well known that activity-dependent motor cortex (MCX) plasticity produces long-term potentiation (LTP) of local cortical circuits, leading to enhanced muscle function, the effects on the corticospinal projection to spinal neurons has not yet been thoroughly studied. Here, we investigate a spinal locus for corticospinal tract (CST) plasticity in anesthetized rats using multichannel recording of motor-evoked, intraspinal local field potentials (LFPs) at the sixth cervical spinal cord segment. We produced LTP by intermittent theta burst electrical stimulation (iTBS) of the wrist area of MCX. Approximately 3 min of MCX iTBS potentiated the monosynaptic excitatory LFP recorded within the CST termination field in the dorsal horn and intermediate zone for at least 15 min after stimulation. Ventrolaterally, in the spinal cord gray matter, which is outside the CST termination field in rats, iTBS potentiated an oligosynaptic negative LFP that was localized to the wrist muscle motor pool. Spinal LTP remained robust, despite pharmacological blockade of iTBS-induced LTP within MCX using MK801, showing that activity-dependent spinal plasticity can be induced without concurrent MCX LTP. Pyramidal tract iTBS, which preferentially activates the CST, also produced significant spinal LTP, indicating the capacity for plasticity at the CST–spinal interneuron synapse. Our findings show CST monosynaptic LTP in spinal interneurons and demonstrate that spinal premotor circuits are capable of further modifying descending MCX control signals in an activity-dependent manner.

Sign in / Sign up

Export Citation Format

Share Document