Slow positive dorsal cord potentials activated by heterosegmental stimuli

Shimoji, Koki; Satô, Yukio; Denda, Sadahei; Takada, Toshikazu; Fukuda, Satoru; Hokari, T.

doi:10.1016/0168-5597(92)90104-j

Cited by 13 publications

(15 citation statements)

References 32 publications

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“…These slow positive potentials (HSP1 and HSP2) might be produced by a feedback loop via supraspinal structures, presumably primary afferent depolarizations, in comparison to the HSPs of our previous studies in the rat (Fig. 4.3) (Shimoji et al, 1990(Shimoji et al, , 1992a. Slow negative potentials were sometimes noted before (5 of 13) and/or after (2 of 13) the HSP1.…”

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confidence: 61%

“…In the rat, paw stimulation alone might be enough to provoke sufficient synchronized volleys in the cord, since the distance between the forepaw and the cord is very much smaller than that in humans. Our recent findings (Shimoji et al, 1992a) indicate that there are two components in HSPs, the early (HSP1) and late (HSP2) components, also suggesting that there are at least two nuclei which send back the feed-back volleys to the spinal cord in response to peripheral nerve stimulation (see Fig. 4.6).…”

Section: The Hsp In Humansmentioning

confidence: 80%

“…The time courses of both the HSP and inhibition of the neuronal activity were found to be similar in these nine WDR neurons. This suggests that the HSP reflects inhibitory activity, probably primary afferent depolarization, activated by a feedback loop via supraspinal structures (Shimoji et al, 1992a). Similar mechanisms may exist in human spinal cord .…”

Section: The Relationship Between Wdr Neuron Activities and Hspmentioning

confidence: 81%

“…This suggests that the origins of the feedback pathway of the cervical P2s are somewhat different from those of the lumbar P2s and also from those of the HSPs. However, since there exist several similarities between the segmental P2s and HSP, such as high vulnerability to anesthetic, complete disappearance after high cervical transection, and comparable responses to graded stimulus intensities, there must be a close relationship in the feedback nuclei and/or pathways between them (Shimoji et al, 1992a). Fig.…”

Section: The Relationship Between Wdr Neuron Activities and Hspmentioning

confidence: 99%

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Evoked Spinal Cord Potentials

Shimoji¹,

Willis²

2006

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PrefaceThe technique of using evoked spinal cord potentials (SCPs) has become an important clinical tool for monitoring spinal cord surgery and diagnosing spinal cord diseases. The technique is a result both of the technical development of recording evoked SCPs from the epidural space without perforation of the dura mater and of the development of medical electronics. Its use as a monitoring tool is based on continuous epidural analgesia with an epidural catheter. Since the first development of epidural recording of evoked SCPs in 1971, the technique has been applied in various institutes, particularly for monitoring during spine or spinal cord surgery and cardiovascular surgery, and recently for diagnosis of spinal cord diseases.Although the results of studies on monitoring during surgery have proved useful, more detailed neurophysiological mechanisms in the origin of each component of evoked SCPs remain to be explained in the area of diagnosis of spinal or central nervous system diseases. Further neurophysiological and neuropharmacological studies of the human spinal cord may contribute to the clinical application of recording evoked SCPs for diagnosis of spinal cord diseases.The aim of this book is to furnish a survey of the neurophysiological and neuropharmacological bases of evoked SCPs with reference to animal studies and the techniques of recording the potentials mainly from the spinal epidural space. The authors have been involved in the field from the beginning of the 1970s. Many illustrations are presented for better understanding the neurophysiological and neuropharmacological backgrounds of monitoring spinal cord functions. Case studies also are presented and discussed to provide more insight into the monitoring and diagnosis of spinal cord dysfunctions and spinal cord diseases. This book is thus appropriate even for students or those new to the fields of clinical neurophysiology, neurosurgery, neurology, orthopedics, and neuroanesthesia who are interested in monitoring spinal cord function during surgery or diagnosing spinal cord diseases. A diverse range of terminology has been used in the literature to date, sometimes leading to misinterpretation of each component in the field of evoked SCPs. To avoid such misinterpretation and to provide readers with an accurate understanding, terminology referring to basic animal studies is used, and lucid explanations are included in this volume.

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mentioning

confidence: 61%

Section: The Hsp In Humansmentioning

confidence: 80%

Section: The Relationship Between Wdr Neuron Activities and Hspmentioning

confidence: 81%

Section: The Relationship Between Wdr Neuron Activities and Hspmentioning

confidence: 99%

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Evoked Spinal Cord Potentials

Shimoji¹,

Willis²

2006

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“…In addition to segmentally evoked spinal cord potentials (segSCP) produced in the segmental dorsal surface of the cord, slow positive potentials (heterosegmentally evoked slow positive potentials (HSP)) can be recorded from the heterosegmental dorsal surface of the spinal cord by peripheral skin nerve stimulation in ketamine-anaesthetized rats [1][2][3], and by large nerve trunk stimulation close to the cord in conscious humans [4,5]. Physiological and pharmacological features of these HSP suggest that they reflect feedback inhibitory activities via supraspinal structures [1][2][3], probably feedback primary afferent depolarizations (PAD) [3], providing an important feedback control system of sensory transmission, including pain. Such HSP might also provide a tool for studying the mechanism of transcutaneous electric nerve stimulation (TENS) or electroacupuncture [5].…”

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confidence: 99%

Central nuclei and spinal pathways in feedback inhibitory spinal cord potentials in ketamine-anaesthetized rats

Denda

Shimoji

Tomita

et al. 1996

British Journal of Anaesthesia

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It has been suggested that heterosegmentally activated slow positive potentials (HSP), recorded from the spinal cord of rat and humans, are feedback inhibitory potentials. The present study was carried out to define ascending and descending spinal tracts and the sites of central nuclei involved in the production of these HSP, and the effects of ketamine on these central nuclei. The spinal cords in ketamine-anaesthetized rats were transected to determine the ascending and descending tracts involved in the production of hindpaw (HP) and forepaw (FP) HSP, respectively. Lesions of the brain at various levels were performed stereotactically during ketamine anaesthesia. Dorsal one-third resection of the cord at the T8-9 level did not affect HSP significantly, while contralateral lesion of the dorsal two-thirds of the cord decreased FP-HSP but not HP-HSP during ketamine. Bilateral transection of the ventral one-third of the cord abolished both HSP. Ablation of the cerebral cortex, cerebellum, thalamus, midbrain and pons did not affect HSP significantly. However, transection of the middle medulla decreased, while transection of the most caudal part of the medulla completely abolished both HSP. Ketamine decreased HSP even in the medulla-spinal cord preparation and the segmental slow positive wave in spinalized animals. In ketamine-anaesthetized rats, ascending and descending spinal tracts involved in the production of HP-HSP and FP-HSP are located bilaterally in the ventrolateral quadrant and in the contralateral lateral funiculus and ventrolateral quadrant, respectively. Principal central nuclei feeding back HSP might be situated diffusely in the medulla down to the caudal part. Ketamine is suggested to suppress these inhibitory feedback potentials predominantly at, and partly even below, the level of the medulla.

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Heterosegmental SCPs (HSPs)

Tomita¹,

Shimoji²

2006

Evoked Spinal Cord Potentials

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Slow positive dorsal cord potentials activated by heterosegmental stimuli

Cited by 13 publications

References 32 publications

Evoked Spinal Cord Potentials

Evoked Spinal Cord Potentials

Central nuclei and spinal pathways in feedback inhibitory spinal cord potentials in ketamine-anaesthetized rats

Heterosegmental SCPs (HSPs)

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