Impaired Organization of Paired-Pulse TMS-Induced I-Waves After Human Spinal Cord Injury

John Cirillo, Finnegan J. Calabro, Monica Perez

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Paired-pulse transcranial magnetic stimulation (TMS) of the human motor cortex results in consecutive facilitatory motor-evoked potential (MEP) peaks in surface electromyography in intact humans. Here, we tested the effect of an incomplete cervical spinal cord injury (SCI) on early (first) and late (second and third) MEP peaks in a resting intrinsic finger muscle. We found that all peaks had decreased amplitude in SCI subjects compared with controls. The second and third peaks were delayed with the third peak also showing an increased duration. The delay of the third peak was smaller than that seen in controls at lower stimulation intensity, suggesting lesser influence of decreased corticospinal inputs. A mathematical model showed that after SCI the third peak aberrantly contributed to spinal motoneurone recruitment, regardless on the motor unit threshold tested. Temporal and spatial aspects of the late peaks correlated with MEP size and hand motor output. Thus, early and late TMS-induced MEP peaks undergo distinct modulation after SCI, with the third peak likely reflecting a decreased ability to summate descending volleys at the spinal level. We argue that the later corticospinal inputs on the spinal cord might be crucial for recruitment of motoneurones after human SCI.

Original languageEnglish (US)
Pages (from-to)2167-2177
Number of pages11
JournalCerebral Cortex
Volume26
Issue number5
DOIs
StatePublished - May 1 2016
Externally publishedYes

Fingerprint

Transcranial Magnetic Stimulation
Motor Evoked Potentials
Spinal Cord Injuries
Motor Neurons
Motor Cortex
Electromyography
Fingers
Spinal Cord
Theoretical Models
Hand
Muscles

Keywords

  • corticospinal volleys
  • primary motor cortex
  • spinal cord injury
  • transcranial magnetic stimulation
  • voluntary movement

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Cognitive Neuroscience

Cite this

Impaired Organization of Paired-Pulse TMS-Induced I-Waves After Human Spinal Cord Injury. / Cirillo, John; Calabro, Finnegan J.; Perez, Monica.

In: Cerebral Cortex, Vol. 26, No. 5, 01.05.2016, p. 2167-2177.

Research output: Contribution to journalArticle

Cirillo, John ; Calabro, Finnegan J. ; Perez, Monica. / Impaired Organization of Paired-Pulse TMS-Induced I-Waves After Human Spinal Cord Injury. In: Cerebral Cortex. 2016 ; Vol. 26, No. 5. pp. 2167-2177.
@article{11d3f8be8c42415ab05777d9707d1aa0,
title = "Impaired Organization of Paired-Pulse TMS-Induced I-Waves After Human Spinal Cord Injury",
abstract = "Paired-pulse transcranial magnetic stimulation (TMS) of the human motor cortex results in consecutive facilitatory motor-evoked potential (MEP) peaks in surface electromyography in intact humans. Here, we tested the effect of an incomplete cervical spinal cord injury (SCI) on early (first) and late (second and third) MEP peaks in a resting intrinsic finger muscle. We found that all peaks had decreased amplitude in SCI subjects compared with controls. The second and third peaks were delayed with the third peak also showing an increased duration. The delay of the third peak was smaller than that seen in controls at lower stimulation intensity, suggesting lesser influence of decreased corticospinal inputs. A mathematical model showed that after SCI the third peak aberrantly contributed to spinal motoneurone recruitment, regardless on the motor unit threshold tested. Temporal and spatial aspects of the late peaks correlated with MEP size and hand motor output. Thus, early and late TMS-induced MEP peaks undergo distinct modulation after SCI, with the third peak likely reflecting a decreased ability to summate descending volleys at the spinal level. We argue that the later corticospinal inputs on the spinal cord might be crucial for recruitment of motoneurones after human SCI.",
keywords = "corticospinal volleys, primary motor cortex, spinal cord injury, transcranial magnetic stimulation, voluntary movement",
author = "John Cirillo and Calabro, {Finnegan J.} and Monica Perez",
year = "2016",
month = "5",
day = "1",
doi = "10.1093/cercor/bhv048",
language = "English (US)",
volume = "26",
pages = "2167--2177",
journal = "Cerebral Cortex",
issn = "1047-3211",
publisher = "Oxford University Press",
number = "5",

}

TY - JOUR

T1 - Impaired Organization of Paired-Pulse TMS-Induced I-Waves After Human Spinal Cord Injury

AU - Cirillo, John

AU - Calabro, Finnegan J.

AU - Perez, Monica

PY - 2016/5/1

Y1 - 2016/5/1

N2 - Paired-pulse transcranial magnetic stimulation (TMS) of the human motor cortex results in consecutive facilitatory motor-evoked potential (MEP) peaks in surface electromyography in intact humans. Here, we tested the effect of an incomplete cervical spinal cord injury (SCI) on early (first) and late (second and third) MEP peaks in a resting intrinsic finger muscle. We found that all peaks had decreased amplitude in SCI subjects compared with controls. The second and third peaks were delayed with the third peak also showing an increased duration. The delay of the third peak was smaller than that seen in controls at lower stimulation intensity, suggesting lesser influence of decreased corticospinal inputs. A mathematical model showed that after SCI the third peak aberrantly contributed to spinal motoneurone recruitment, regardless on the motor unit threshold tested. Temporal and spatial aspects of the late peaks correlated with MEP size and hand motor output. Thus, early and late TMS-induced MEP peaks undergo distinct modulation after SCI, with the third peak likely reflecting a decreased ability to summate descending volleys at the spinal level. We argue that the later corticospinal inputs on the spinal cord might be crucial for recruitment of motoneurones after human SCI.

AB - Paired-pulse transcranial magnetic stimulation (TMS) of the human motor cortex results in consecutive facilitatory motor-evoked potential (MEP) peaks in surface electromyography in intact humans. Here, we tested the effect of an incomplete cervical spinal cord injury (SCI) on early (first) and late (second and third) MEP peaks in a resting intrinsic finger muscle. We found that all peaks had decreased amplitude in SCI subjects compared with controls. The second and third peaks were delayed with the third peak also showing an increased duration. The delay of the third peak was smaller than that seen in controls at lower stimulation intensity, suggesting lesser influence of decreased corticospinal inputs. A mathematical model showed that after SCI the third peak aberrantly contributed to spinal motoneurone recruitment, regardless on the motor unit threshold tested. Temporal and spatial aspects of the late peaks correlated with MEP size and hand motor output. Thus, early and late TMS-induced MEP peaks undergo distinct modulation after SCI, with the third peak likely reflecting a decreased ability to summate descending volleys at the spinal level. We argue that the later corticospinal inputs on the spinal cord might be crucial for recruitment of motoneurones after human SCI.

KW - corticospinal volleys

KW - primary motor cortex

KW - spinal cord injury

KW - transcranial magnetic stimulation

KW - voluntary movement

UR - http://www.scopus.com/inward/record.url?scp=84965169236&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84965169236&partnerID=8YFLogxK

U2 - 10.1093/cercor/bhv048

DO - 10.1093/cercor/bhv048

M3 - Article

C2 - 25814508

AN - SCOPUS:84965169236

VL - 26

SP - 2167

EP - 2177

JO - Cerebral Cortex

JF - Cerebral Cortex

SN - 1047-3211

IS - 5

ER -