To the Editor.
—Munschauer et al1 describe an interesting example of a man with a magnetic resonance image that demonstrated paramedian ventral pontine damage. He breathed normally at rest and in response to carbon dioxide stimulation, but he was unable to initiate either breathing or swallowing by voluntary effort. Recent, indirect, physiologic studies employing functional activation of cerebral blood flow2 indicate that at least the diaphragm enjoys direct representation in the cerebral motor cortex, premotor cortex, supplementary motor area, and cerebellum. The results of transcranial magnetic stimulation3 confirm the finding and suggest that considerable lateralization exists in cerebral diaphragmatic control since unilateral stimulation over motor-premotor cortex from either hemisphere evokes predominantly contralateral diaphragmatic movement in a manner similar to that observed with voluntary acts of the limbs. Evidently, this higher, cerebral regulation of respiratory striated muscle subserves the major behavioral functions of the system.Munschauer et al,
Plum F. Breathing Is Controlled Independently by Voluntary, Emotional, and Metabolically Related Pathways. Arch Neurol. 1992;49(5):441. doi:10.1001/archneur.1992.00530290023006