Lesions in this area, his noeud vital, stopped respiration in animals.
Over the next century or so, researchers tried to better define the boundaries of the noeud vital. Initially, they mostly performed lesion experiments, and then later they began recording the electrical activity of the brains of sedated cats.
In the mid-1980s, Smith joined Feldman's group and began an effort to further pinpoint the noeud vital. He painstakingly carved out pieces of the newborn rat brainstem and documented whether the respiratory rhythm persisted.
At the Society for Neuroscience meeting, Boston researchers investigating the origin of SIDS reported that the receptor for substance P may have led them to the human noeud vital. "We look at sites in the brainstem that are critical for the control of things like respiratory function, heart rate, and temperature control," explains David Paterson of Children's Hospital in Boston.
An equally big question for McCrimmon and others who embrace the PBC as the noeud vital is how the basic respiratory rhythm of eupnea arises, seemingly from fewer than 1,000 nerve cells.
ONE NODE OR TWO It may take longer to address the tantalizing question of whether there's a more primitive noeud vital within the mammalian brain, an issue Feldman broached at the Society for Neuroscience meeting.