Rhythmic respiratory breathing continuously adapts to the organism's posture, activity level, speech, and can reveal whether someone is calm, agitated, or scared. Plasticity of the mechanisms involved in respiratory behavior is modulated in part by the pre-Bötzinger complex. Disruption causes irreversible loss or major disruption of breathing in vivo. The frequency and amplitude change according to the behavioral and metabolic demands of the organism it controls. Breathing is thus extremely sensitive to the internal state of the organism. The pre-Bötzinger complex is a rhythm generating network, which is composed of micro networks that function within larger networks to create characteristic rhythms and breathing patterns, including eupneic, sigh, and gasping activities. This single neuronal network can create multiple respiratory rhythmic patterns and is by itself both necessary and sufficient to generate respiratory rhythms.