Edgar Lumsden's pioneering experiments in the nineteen twenties revolutionized our understanding of respiratory control. Using anesthetized cats, he systematically cut through different levels of the brainstem to identify which regions controlled breathing. His work revealed the complex neural networks that regulate our most vital function.
Lumsden's methodology was systematic and precise. He used anesthetized cats and made serial transections at different brainstem levels. After each cut, he carefully observed changes in breathing patterns. By correlating the location of each cut with the resulting respiratory changes, he could map the functional organization of breathing control centers.
Lumsden's transection experiments revealed remarkable findings. Cuts above the pons left breathing normal, but cuts through the upper pons made breathing irregular. Most dramatically, cuts through the lower pons caused prolonged inspiration called apneusis. These results identified three distinct respiratory centers: the pneumotaxic center in the upper pons, the apneustic center in the lower pons, and the basic rhythm generators in the medulla.
Lumsden's experiments revealed a sophisticated hierarchical control system for breathing. The medulla generates the basic respiratory rhythm, while the pons provides crucial modulation. The pneumotaxic center terminates inspiration, preventing over-inflation, while the apneustic center promotes inspiration. Higher brain centers can override this automatic system for voluntary control, creating an adaptive breathing mechanism.
Lumsden's pioneering transection experiments fundamentally transformed our understanding of respiratory control. His systematic approach identified the pneumotaxic, apneustic, and medullary centers, establishing the hierarchical organization that governs breathing. This foundational work continues to influence modern respiratory neuroscience and provides crucial insights for understanding breathing disorders in clinical practice.