title: Short-term training-dependent plasticity of the corticospinal diaphragm control in normal humans.
abstract: Mammalian ventilation is driven by automatic structures producing "metabolic" ventilation. Respiratory neuroplasticity can adapt this control to developmental, environmental, and disease-related changes. A corticospinal diaphragm pathway accounts for behavioural disruptions of metabolic ventilation. It should be sensitive to use-dependent short-term plasticity. However, the brainstem-generated permanent diaphragm activity could alter the learning-related corticospinal plasticity (metaplasticity). To test this hypothesis, eight healthy volunteers (six women, 21-25) were studied before and after having learnt to produce prominent diaphragm contractions during voluntary inspiratory manoeuvres. Diaphragm training resulted in (1) a decreased liminal stimulation intensities; (2) an increased number of responding sites on the diaphragm mapping with focal stimulation (5.1+/-3.3 versus 9+/-4.4, p=0.004 in relaxed conditions; 8.9+/-5 versus 15.3+/-4.5, p<0.0001, with underlying voluntary facilitation); (3) shortened motor evoked potentials latencies in response to non-focal stimulation (17.2+/-1.6 ms versus 16.2+/-1.4 ms, p=0.03 in relaxed conditions, and 16.8+/-1.1 ms versus 15.2+/-1.6 ms, p=0.003, with facilitation). These results are closely comparable with similar data in locomotor muscle. They provide a neurophysiological basis for the capacity of normal humans to rapidly acquire diaphragmatic skills.
authors.affiliation: Laboratoire de Physiopathologie Respiratoire et Unité de Réanimation, Service de Pneumologie, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Demoule
authors.forename: Eric
authors.initials: E
authors.lastname: Verin
authors.forename: Sophie Tezenas du
authors.initials: ST
authors.lastname: Montcel
authors.forename: Thomas
authors.initials: T
authors.lastname: Similowski
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D001933:Brain Stem / Q000502:physiology; D003964:Diaphragm / Q000294:innervation / Q000502:physiology*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D009046:Motor Neurons / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D010791:Phrenic Nerve / Q000166:cytology / Q000502:physiology; D011214:Practice, Psychological; D011597:Psychomotor Performance / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology*; D011712:Pyramidal Tracts / Q000502:physiology*; D012016:Reference Values; D050781:Transcranial Magnetic Stimulation