The pre-Bötzinger complex produces two types of breathing rhythms under normal levels of oxygen. In eupnea, or normal breathing, the pre-BötC generates a rhythm that is fast and low in amplitude. Sighs, on the other hand, consist of a slow and large amplitude rhythm. Each type of rhythm is generated by the same neurons in the pre-Bötzinger complex, but through different mechanisms, receptors, and ion currents that are controlled by changes in the behavior or environment of the organism. Under low levels of oxygen, the pre-Bötzinger complex needs to rearrange the activity of its neurons and requires the assistance of other brain structures, like the pons, to generate gasping. Gasping is characterized by a rhythm that has faster rise, shorter bursts, and lower frequency.