Cortical and spinal evoked potential response to electrical stimulation in human rectum

A single, short-duration electrical stimulus delivered to one olfactory bulb evokes a potential in the contralateral bulb. As recorded with a unipolar electrode, the potential is negative central to, and positive peripheral to the external plexiform layer. Bipolar recordings from multiple sites show that the potential is not actively propagated. The potential summates in response to tetanic stimulation and is blocked by anoxia and dimethyl ether d-tubocurarine. In addition to confirming the existence of an interolfactory bulb system, the electrophysiological evidence in conjunction with known anatomical relationships strongly suggests that the evoked potential is a postsynaptic potential of the internal granular cells.

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Cerebral-evoked potential responses following direct vagal and esophageal electrical stimulation in humans

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1993.264.3.g486 ◽

1993 ◽

Vol 264 (3) ◽

pp. G486-G491 ◽

Cited By ~ 10

Author(s):

G. Tougas ◽

P. Hudoba ◽

D. Fitzpatrick ◽

R. H. Hunt ◽

A. R. Upton

Keyword(s):

Electrical Stimulation ◽

Evoked Potential ◽

Vagal Stimulation ◽

Direct Electrical Stimulation ◽

Sensory Pathways ◽

Afferent Fibers ◽

Health And Disease ◽

Esophageal Sphincter ◽

Afferent Response ◽

Stimulation Of

Cerebral evoked responses following direct electrical stimulation of the vagus and esophagus were compared in 8 epileptic subjects and with those recorded after esophageal stimulation in 12 healthy nonepileptic controls. Direct vagal stimulation was performed using a left cervical vagal pacemaker, which is used in the treatment of epilepsy. Esophageal stimulation was obtained with the use of an esophageal assembly incorporating two electrodes positioned 5 and 20 cm orad to the lower esophageal sphincter. Evoked potential responses were recorded with the use of 20 scalp electrodes. The evoked potential responses consisted of three distinct negative peaks and were similar with the use of either vagal or esophageal stimulation. The measured conduction velocity of the afferent response was 7.5 m/s in epileptic subjects and 10 m/s in healthy controls, suggesting that afferent conduction is through A delta-fibers rather than slower C afferent fibers. We conclude that the cortical-evoked potential responses following esophageal electrical stimulation are comparable to direct electrical stimulation of the vagus nerve and involve mostly A delta-fibers. This approach provides a method for the assessment of vagal afferent gastrointestinal sensory pathways in health and disease.

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Octreotide reduces perception of rectal electrical stimulation by spinal afferent pathway inhibition

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1995.269.6.g821 ◽

1995 ◽

Vol 269 (6) ◽

pp. G821-G826 ◽

Cited By ~ 4

Author(s):

W. D. Chey ◽

A. Beydoun ◽

D. J. Roberts ◽

W. L. Hasler ◽

C. Owyang

Keyword(s):

Electrical Stimulation ◽

Evoked Potentials ◽

Evoked Potential ◽

Double Blind ◽

Afferent Pathways ◽

Normal Volunteers ◽

Site Of Action ◽

Cerebral Evoked Potentials ◽

Pathway Inhibition ◽

Irritable Bowel

Octreotide reduces perception of rectal distension in normal volunteers and irritable bowel patients. To localize octreotide's site of action, perceptual and evoked potential responses to rectal electrical stimulation were tested in seven normal volunteers after double-blind octreotide (100 micrograms 2) or placebo. After octreotide, the currents needed to elicit threshold perception of square-wave impulses delivered to the rectum were 29% higher than after placebo. When electrical stimulation was delivered at constant currents 50% above threshold, rectal perception scores were significantly reduced after octreotide compared with placebo. Rectal electrical stimulation led to characteristic and reproducible cerebral evoked potentials. Octreotide had no effect on latencies, but reduced peak-to-peak amplitudes by 35% compared with placebo. Rectal electrical stimulation also led to characteristic and reproducible spinal evoked potentials. Octreotide had no effect on spinal latencies, but reduced peak-to-peak amplitudes by 51%. In conclusion, octreotide reduces perception of rectal electrical stimulation, which is associated with inhibition of cerebral and spinal evoked potential amplitude, indicating effects on spinal afferent pathways.

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Transplantation of eyes to the adult rat brain: Histological findings and light-evoked potential response

Life Sciences ◽

10.1016/0024-3205(80)90132-0 ◽

1980 ◽

Vol 27 (6) ◽

pp. 503-510 ◽

Cited By ~ 15

Author(s):

William J. Freed ◽

Richard Jed Wyatt

Keyword(s):

Rat Brain ◽

Evoked Potential ◽

Histological Findings ◽

Potential Response ◽

Adult Rat ◽

Adult Rat Brain

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The second sensory area in humans: Evoked potential and electrical stimulation studies

Annals of Neurology ◽

10.1002/ana.410170212 ◽

1985 ◽

Vol 17 (2) ◽

pp. 177-184 ◽

Cited By ~ 93

Author(s):

H. Lüders ◽

R. P. Lesser ◽

D. S. Dinner ◽

J. F. Hahn ◽

V. Salanga ◽

...

Keyword(s):

Electrical Stimulation ◽

Evoked Potential ◽

Sensory Area

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Motor evoked potential monitoring of the vagus nerve with transcranial electrical stimulation during skull base surgeries

Journal of Neurosurgery ◽

10.3171/2012.10.jns12383 ◽

2013 ◽

Vol 118 (1) ◽

pp. 195-201 ◽

Cited By ~ 21

Author(s):

Eiji Ito ◽

Masahiro Ichikawa ◽

Takeshi Itakura ◽

Hitoshi Ando ◽

Yuka Matsumoto ◽

...

Keyword(s):

Electrical Stimulation ◽

Endotracheal Tube ◽

Skull Base ◽

Evoked Potential ◽

Control Level ◽

Motor Evoked Potential ◽

Transcranial Electrical Stimulation ◽

Postoperative Dysphagia ◽

Swallowing Function ◽

Surface Electrodes

Object Dysphasia is one of the most serious complications of skull base surgeries and results from damage to the brainstem and/or cranial nerves involved in swallowing. Here, the authors propose a method to monitor the function of the vagus nerve using endotracheal tube surface electrodes and transcranial electrical stimulation during skull base surgeries. Methods Fifteen patients with skull base or brainstem tumors were enrolled. The authors used surface electrodes of an endotracheal tube to record compound electromyographic responses from the vocalis muscle. Motor neurons were stimulated using corkscrew electrodes placed subdermally on the scalp at C3 and C4. During surgery, the operator received a warning when the amplitude of the vagal motor evoked potential (MEP) decreased to less than 50% of the control level. After surgery, swallowing function was assessed clinically using grading criteria. Results In 5 patients, vagal MEP amplitude permanently deteriorated to less than 50% of the control level on the right side when meningiomas were dissected from the pons or basilar artery, or when a schwannoma was dissected from the vagal rootlets. These 5 patients had postoperative dysphagia. At 4 weeks after surgery, 2 patients still had dysphagia. In 2 patients, vagal MEPs of one side transiently disappeared when the tumors were dissected from the brainstem or the vagal rootlets. After surgery, both patients had dysphagia, which recovered in 4 weeks. In 7 patients, MEP amplitude was consistent, maintaining more than 50% of the control level throughout the operative procedures. After surgery all 7 patients were neurologically intact with normal swallowing function. Conclusions Vagal MEP monitoring with transcranial electrical stimulation and endotracheal tube electrode recording was a safe and effective method to provide continuous real-time information on the integrity of both the supranuclear and infranuclear vagal pathway. This method is useful to prevent intraoperative injury of the brainstem corticobulbar tract or the vagal rootlets and to avoid the postoperative dysphagia that is often associated with brainstem or skull base surgeries.

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