Neural Control of Breathing in Parkinson's Disease

Control of breathing is predominantly regulated by feedback of the central chemoreceptors. All chemoreceptors are sensitive to changes in partial pressure of carbon dioxide and via acid-base reactions to hydrogen concentration. The hypercapnic ventilatory response test shows the relationship between end-tidal PCO2 and the resulting minute ventilation.

The RREP is a measure of cerebral cortical activity elicited by short inspiratory occlusion or breathing against inspiratory resistive loads and quantifies the initial arrival and further processing of sensory afferent respiratory information in the cortex.

Transcranial magnetic stimulation of the diaphragm is an established tool for investigating the cortical excitability related to breathing. TMS will be delivered over the vertex using a magnetic stimulator and a 110mm double cone coil.