Where is the Cortical Representation of the Diaphragm in Man?
The use of transcranial stimulation, initially using electrical techniques1 and subsequently using magnetic techniques2 have demonstrated a rapid oligosynaptic pathway from the cortex to the diaphragm. These studies do not however establish the exact area of the cortex that is associated with activation of the diaphragm. The early work of Foerster3 identified a site near the vertex which when stimulated produced hiccough but no detail is available. Use has been made of an improved magnetic coil design (figure-of-eight) to ‘Map’ the unilateral cortical representation of the inspiratory muscles; essentially the diaphragm. The work of Rösier et al4 had showed that a figure-of-eight coil was better at exciting specific areas of the motor cortex; essentially showing an extended peak current along the intersection of the two coils. He had also shown the importance of the direction of the principal stimulating current vector.
KeywordsTranscranial Magnetic Stimulation Motor Cortex Compound Muscle Action Potential Inspiratory Muscle Cortical Representation
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- 3.O. Foerster, Motorische felder und bahen in: Handbook der neurologie, O. Bumke and O. Foerster ed., Springer, Berlin (1936).Google Scholar