Distribution and course of cortico-respiratory projections for voluntary activation in man: A transcranial magnetic stimulation study in healthy subjects and patients with cerebral ischemia

• Published in: Journal of neurology Vol. 249; no. 6; pp. 735 - 744
• Main Authors: URBAN, Peter Paul, MORGENSTERN, Michael, BRAUSE, Kai, WICHT, Susanne, VUKUREVIC, Goran, KESSLER, Stefan, STOETER, Peter
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.06.2002; Springer Nature B.V
• Subjects: Adult; Aged; Biological and medical sciences; Brain Ischemia - pathology; Brain Ischemia - physiopathology; Diaphragm - innervation; Diaphragm - physiopathology; Electric Stimulation; Female; Functional Laterality - physiology; Humans; Male; Medical sciences; Middle Aged; Motor Cortex - pathology; Motor Cortex - physiopathology; Muscle, Skeletal - innervation; Muscle, Skeletal - physiopathology; Neurology; Paresis - pathology; Paresis - physiopathology; Phrenic Nerve - physiopathology; Pyramidal Tracts - pathology; Pyramidal Tracts - physiopathology; Reaction Time - physiology; Respiratory Insufficiency - etiology; Respiratory Insufficiency - pathology; Respiratory Insufficiency - physiopathology; Respiratory Muscles - innervation; Respiratory Muscles - physiopathology; Respiratory Physiological Phenomena; Spinal Cord - pathology; Spinal Cord - physiopathology; Stroke - pathology; Stroke - physiopathology; Transcranial Magnetic Stimulation; Vascular diseases and vascular malformations of the nervous system; Human; Pyramidal tract; Nervous system diseases; Cardiovascular disease; Exploration; Stimulation; Cerebral disorder; Vascular disease; Transcranial route; Magnetic; Ischemia; Respiratory muscle; Central nervous system disease; Diaphragm; Cerebrovascular disease; Brain (vertebrata)
• ISSN: 0340-5354; 1432-1459
• DOI: 10.1007/s00415-002-0702-8

The function and course of the cortico-respiratory projections in man are not yet well established. In 30 normal volunteers respiratory muscles were activated by magnetic stimulation of the motor cortex and the cervical and thoracic spinal roots with bilateral recordings from the respiratory muscles. Following cortical stimulation contralateral responses were obtained in all subjects during voluntary inspiration showing a mean latency and amplitude of 13.4+/-1.4ms/1.6+/-1.2 mV (stimulation of the left hemisphere) and 13.2+/-1.3ms/2.5+/-2.5 mV (stimulation of the right hemisphere). Ipsilateral responses were obtained in only 18 (right side) and 21 (left side) subjects and had a significantly (p < 0.001) longer mean latency and lower mean amplitude than the contralateral responses. In 31 patients with impairment of the cortico-respiratory projections due to cerebral infarction demonstrated by magnetic resonance imaging studies, the responsible lesion topography was analysed. We found that, 1. the voluntary activation of respiratory muscles is mediated predominantly by the contralateral motor cortex, 2. the descending cortico-respiratory projections are located within the pyramidal tract, and 3. the cortico-respiratory projections to the respiratory muscles are frequently affected in patients with hemiparesis due to acute stroke. These findings might explain the increased incidence of pneumonia at the hemiparetic side in patients with cerebral ischemia as shown in previous studies.