The pathophysiology of periodic breathing remains poorly understood. Our hypothesis regarding the mechanisms of this abnormal ventilatory pattern is based on comparative physiology. Periodic ventilation is indeed the usual ventilatory pattern of many lower vertebrates. Moreover, even isolated in VITRO, the tadpole brainstem still produces a periodic ventilatory rhythm, characterized by clusters of ventilatory discharges. In this model, the agonist of the GABA-B receptor, the baclofen, transforms the periodic pattern into a regular one. Of note, the baclofen is already used in the treatment of some human diseases, especially against spasticity.