When we breathe there are a couple of neurons or groups of neurons called nuclei present in the medulla. They send action potential signals that sort of ramp up to the muscles. The ventral group is probably the most important for taking a breath in, taking a breath out. If you've got damage in the PONs your quite breath in and quite breath out is a bit erratic right? So it just shows you that it just smooths out that transition period between breathing in, breathing out. We're first going to focus on just quiet breathing.