Interdisciplinary approaches of transcranial magnetic stimulation applied to a respiratory neuronal circuitry model

PLoS One. 2014 Nov 18;9(11):e113251. doi: 10.1371/journal.pone.0113251. eCollection 2014.

Abstract

Respiratory related diseases associated with the neuronal control of breathing represent life-threatening issues and to date, no effective therapeutics are available to enhance the impaired function. The aim of this study was to determine whether a preclinical respiratory model could be used for further studies to develop a non-invasive therapeutic tool applied to rat diaphragmatic neuronal circuitry. Transcranial magnetic stimulation (TMS) was performed on adult male Sprague-Dawley rats using a human figure-of-eight coil. The largest diaphragmatic motor evoked potentials (MEPdia) were recorded when the center of the coil was positioned 6 mm caudal from Bregma, involving a stimulation of respiratory supraspinal pathways. Magnetic shielding of the coil with mu metal reduced magnetic field intensities and improved focality with increased motor threshold and lower amplitude recruitment curve. Moreover, transynaptic neuroanatomical tracing with pseudorabies virus (applied to the diaphragm) suggest that connections exist between the motor cortex, the periaqueductal grey cell regions, several brainstem neurons and spinal phrenic motoneurons (distributed in the C3-4 spinal cord). These results reveal the anatomical substrate through which supraspinal stimulation can convey descending action potential volleys to the spinal motoneurons (directly or indirectly). We conclude that MEPdia following a single pulse of TMS can be successfully recorded in the rat and may be used in the assessment of respiratory supraspinal plasticity. Supraspinal non-invasive stimulations aimed to neuromodulate respiratory circuitry will enable new avenues of research into neuroplasticity and the development of therapies for respiratory dysfunction associated with neural injury and disease (e.g. spinal cord injury, amyotrophic lateral sclerosis).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Diaphragm / innervation*
  • Diaphragm / physiology
  • Disease Models, Animal*
  • Evoked Potentials, Motor / physiology
  • Interdisciplinary Communication
  • Male
  • Neuroanatomical Tract-Tracing Techniques
  • Rats
  • Rats, Sprague-Dawley
  • Respiration Disorders / physiopathology
  • Respiration Disorders / therapy*
  • Respiratory Mechanics / physiology*
  • Statistics, Nonparametric
  • Transcranial Magnetic Stimulation / instrumentation
  • Transcranial Magnetic Stimulation / methods*

Grants and funding

This work was supported by funding from the European Union Seventh framework Programme (FP7/2007-2013) under grant agreement No. 246556 (European project RBUCE-UP), HandiMedEx allocated by the French Public Investment Board, the Chancellerie des Universités de Paris (Legs Poix), the « Centre d’Assistance Respiratoire à Domicile d’Ile de France (CARDIF) », the « Fonds de Dotation de Recherche en Santé Respiratoire » and LVL Medical. Financial support for neuroanatomical studies was provided through internal funds awarded to Michael Lane at Drexel University – College of Medicine, Department of Neurobiology & Anatomy. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.