Document Detail

Dissociation of human thalamic and cortical SEP gating as revealed by intrathalamic recordings under muscle relaxation.
MedLine Citation:
PMID:  12468039     Owner:  NLM     Status:  MEDLINE    
'Gating' refers to a reduction of cortical somatosensory evoked potentials (SEP) under multiple simultaneous afferent inputs. This study used the opportunity for intrathalamic recordings in patients with movement disorders to clarify to what extent cortical SEP gating is preceded by thalamic gating. Recordings were performed in 10 patients, narcotised by intravenous propofol when receiving implantation of a therapeutic deep brain stimulator system. SEP were elicited by an 8.1-Hz median nerve stimulation at twice motor threshold and were recorded simultaneously from both intrathalamic and scalp electrodes before and after the application of the depolarising muscle blocker succinylcholine which eliminated both the background muscular tone and the repetitive muscle twitches caused by the median nerve stimulation. Peripheral compound action potentials recorded at the upper arm remained unchanged after complete muscle relaxation, proving a continuously effective nerve stimulation. In contrast, the primary cortical SEP component (N20) was significantly increased under succinylcholine (+17%). This cortical release from gating was not paralleled, however, by an increased thalamic response; rather, the primary thalamic response (P16) showed a slight (-9%) but highly significant amplitude reduction. As the recordings were performed in narcotised patients, any potentially variable attentional bias on part of the subjects can be excluded as confounding factor when comparing the two experimental conditions with vs. without reafferent somatosensory inflow. Thus, given the high signal-to-noise ratio of intrathalamically recorded SEP, the present study shows a distinct thalamo-cortical dissociation with the primary somatosensory cortex representing the predominant level exhibiting SEP gating.
Fabian Klostermann; René Gobbele; Helmut Buchner; Gabriel Curio
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Brain research     Volume:  958     ISSN:  0006-8993     ISO Abbreviation:  Brain Res.     Publication Date:  2002 Dec 
Date Detail:
Created Date:  2002-12-06     Completed Date:  2003-02-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0045503     Medline TA:  Brain Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  146-51     Citation Subset:  IM    
Copyright Information:
Copyright 2002 Elsevier Science B.V.
Neurophysics Group, Department of Neurology, Universitätsklinikum Benjamin Franklin, Freie Universitaet, Berlin, Germany.
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MeSH Terms
Action Potentials / physiology
Afferent Pathways / physiology*
Electric Stimulation Therapy
Evoked Potentials, Somatosensory / physiology*
Median Nerve / physiology*
Middle Aged
Movement Disorders / therapy
Muscle Relaxation / drug effects,  physiology
Neural Conduction / physiology
Neural Inhibition / physiology*
Neuromuscular Depolarizing Agents / pharmacology
Reaction Time / physiology
Somatosensory Cortex / physiology*
Succinylcholine / pharmacology
Ventral Thalamic Nuclei / physiology*
Reg. No./Substance:
0/Neuromuscular Depolarizing Agents; 306-40-1/Succinylcholine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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