Short and middle-latency Median Nerve (MN) SEPs recorded by depth electrodes in human pre-SMA and SMA-proper

C. Barba, M. Valeriani, G. Colicchio, F. Mauguière

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Objective: To analyse waveforms, latencies and amplitudes of Median Nerve (MN) SEPs recorded by stereotactically electrodes implanted in the SMA of 14 epileptic patients (9 in pre-SMA,3 in SMA-proper, 2 in both) in order to evaluate which short and middle-latency SEPs are generated in this area and which could be the physiological relevance of these responses. Methods: Short and middle-latency MN SEPs were recorded by chronically implanted electrodes in the fronto-temporal cortex and in particular in the mesial frontal region of 14 drug-resistant epileptic patients. MN stimulations of 100 μs were delivered by skin electrodes at the wrist; stimulus intensity was adjusted slightly above the motor threshold. Results: The main result of this study is that middle-latency SEPs were originated in pre-SMA but not in SMA-proper as demonstrated by both referential and bipolar recordings. In particular off-line computed bipolar traces between neighbouring contacts implanted in the pre-SMA and in the frontal external regions showed a phase reversal at the deepest contacts located in pre-SMA. Conversely, bipolar recordings between neighbouring contacts implanted in the SMA-proper and in the frontal external regions showed inversion recovery at more superficial contacts, implanted in area 6. Finally, we confirmed that no short-latency MN SEP (and in particular the N30) is originated in the whole SMA. Conclusions: Among premotor areas, somatosensory inputs seem to reach pre-SMA and area 6 but not SMA-proper. Significance: This study assessed that no scalp SEP in the first 100 ms after MN stimulus could be generated in SMA-proper.

Original languageEnglish
Pages (from-to)2664-2674
Number of pages11
JournalClinical Neurophysiology
Volume116
Issue number11
DOIs
Publication statusPublished - Nov 2005

Fingerprint

Median Nerve
Electrodes
Implanted Electrodes
Motor Cortex
Temporal Lobe
Scalp
Wrist
Skin
Pharmaceutical Preparations

Keywords

  • Epilepsy surgery
  • Evoked potentials
  • Somatosensory system

ASJC Scopus subject areas

  • Clinical Neurology
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Sensory Systems
  • Physiology (medical)

Cite this

Short and middle-latency Median Nerve (MN) SEPs recorded by depth electrodes in human pre-SMA and SMA-proper. / Barba, C.; Valeriani, M.; Colicchio, G.; Mauguière, F.

In: Clinical Neurophysiology, Vol. 116, No. 11, 11.2005, p. 2664-2674.

Research output: Contribution to journalArticle

@article{9f68b8c5bb8c4814bbea3583c8a594c0,
title = "Short and middle-latency Median Nerve (MN) SEPs recorded by depth electrodes in human pre-SMA and SMA-proper",
abstract = "Objective: To analyse waveforms, latencies and amplitudes of Median Nerve (MN) SEPs recorded by stereotactically electrodes implanted in the SMA of 14 epileptic patients (9 in pre-SMA,3 in SMA-proper, 2 in both) in order to evaluate which short and middle-latency SEPs are generated in this area and which could be the physiological relevance of these responses. Methods: Short and middle-latency MN SEPs were recorded by chronically implanted electrodes in the fronto-temporal cortex and in particular in the mesial frontal region of 14 drug-resistant epileptic patients. MN stimulations of 100 μs were delivered by skin electrodes at the wrist; stimulus intensity was adjusted slightly above the motor threshold. Results: The main result of this study is that middle-latency SEPs were originated in pre-SMA but not in SMA-proper as demonstrated by both referential and bipolar recordings. In particular off-line computed bipolar traces between neighbouring contacts implanted in the pre-SMA and in the frontal external regions showed a phase reversal at the deepest contacts located in pre-SMA. Conversely, bipolar recordings between neighbouring contacts implanted in the SMA-proper and in the frontal external regions showed inversion recovery at more superficial contacts, implanted in area 6. Finally, we confirmed that no short-latency MN SEP (and in particular the N30) is originated in the whole SMA. Conclusions: Among premotor areas, somatosensory inputs seem to reach pre-SMA and area 6 but not SMA-proper. Significance: This study assessed that no scalp SEP in the first 100 ms after MN stimulus could be generated in SMA-proper.",
keywords = "Epilepsy surgery, Evoked potentials, Somatosensory system",
author = "C. Barba and M. Valeriani and G. Colicchio and F. Maugui{\`e}re",
year = "2005",
month = "11",
doi = "10.1016/j.clinph.2005.07.022",
language = "English",
volume = "116",
pages = "2664--2674",
journal = "Clinical Neurophysiology",
issn = "1388-2457",
publisher = "Elsevier Ireland Ltd",
number = "11",

}

TY - JOUR

T1 - Short and middle-latency Median Nerve (MN) SEPs recorded by depth electrodes in human pre-SMA and SMA-proper

AU - Barba, C.

AU - Valeriani, M.

AU - Colicchio, G.

AU - Mauguière, F.

PY - 2005/11

Y1 - 2005/11

N2 - Objective: To analyse waveforms, latencies and amplitudes of Median Nerve (MN) SEPs recorded by stereotactically electrodes implanted in the SMA of 14 epileptic patients (9 in pre-SMA,3 in SMA-proper, 2 in both) in order to evaluate which short and middle-latency SEPs are generated in this area and which could be the physiological relevance of these responses. Methods: Short and middle-latency MN SEPs were recorded by chronically implanted electrodes in the fronto-temporal cortex and in particular in the mesial frontal region of 14 drug-resistant epileptic patients. MN stimulations of 100 μs were delivered by skin electrodes at the wrist; stimulus intensity was adjusted slightly above the motor threshold. Results: The main result of this study is that middle-latency SEPs were originated in pre-SMA but not in SMA-proper as demonstrated by both referential and bipolar recordings. In particular off-line computed bipolar traces between neighbouring contacts implanted in the pre-SMA and in the frontal external regions showed a phase reversal at the deepest contacts located in pre-SMA. Conversely, bipolar recordings between neighbouring contacts implanted in the SMA-proper and in the frontal external regions showed inversion recovery at more superficial contacts, implanted in area 6. Finally, we confirmed that no short-latency MN SEP (and in particular the N30) is originated in the whole SMA. Conclusions: Among premotor areas, somatosensory inputs seem to reach pre-SMA and area 6 but not SMA-proper. Significance: This study assessed that no scalp SEP in the first 100 ms after MN stimulus could be generated in SMA-proper.

AB - Objective: To analyse waveforms, latencies and amplitudes of Median Nerve (MN) SEPs recorded by stereotactically electrodes implanted in the SMA of 14 epileptic patients (9 in pre-SMA,3 in SMA-proper, 2 in both) in order to evaluate which short and middle-latency SEPs are generated in this area and which could be the physiological relevance of these responses. Methods: Short and middle-latency MN SEPs were recorded by chronically implanted electrodes in the fronto-temporal cortex and in particular in the mesial frontal region of 14 drug-resistant epileptic patients. MN stimulations of 100 μs were delivered by skin electrodes at the wrist; stimulus intensity was adjusted slightly above the motor threshold. Results: The main result of this study is that middle-latency SEPs were originated in pre-SMA but not in SMA-proper as demonstrated by both referential and bipolar recordings. In particular off-line computed bipolar traces between neighbouring contacts implanted in the pre-SMA and in the frontal external regions showed a phase reversal at the deepest contacts located in pre-SMA. Conversely, bipolar recordings between neighbouring contacts implanted in the SMA-proper and in the frontal external regions showed inversion recovery at more superficial contacts, implanted in area 6. Finally, we confirmed that no short-latency MN SEP (and in particular the N30) is originated in the whole SMA. Conclusions: Among premotor areas, somatosensory inputs seem to reach pre-SMA and area 6 but not SMA-proper. Significance: This study assessed that no scalp SEP in the first 100 ms after MN stimulus could be generated in SMA-proper.

KW - Epilepsy surgery

KW - Evoked potentials

KW - Somatosensory system

UR - http://www.scopus.com/inward/record.url?scp=27544473267&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=27544473267&partnerID=8YFLogxK

U2 - 10.1016/j.clinph.2005.07.022

DO - 10.1016/j.clinph.2005.07.022

M3 - Article

VL - 116

SP - 2664

EP - 2674

JO - Clinical Neurophysiology

JF - Clinical Neurophysiology

SN - 1388-2457

IS - 11

ER -