FIG. 15:  Based on the loop-gain theory discussed in the previous Figures, the feedback system may be altered at various points to produce the periodic, or cyclic breathing of CSA.  For example, in Op-CSA, the controller gain may be increased due to the direct centrally depressing effects of the opioids, and for any given decrease in PCO₂, the responding minute ventilation drop could be exaggerated.  There are also reports that loop gain could vary with different disturbances.  So for example, in opioid users the loop gain for CO₂ may be low, but for hypoxemia it may be high, and these desynchronous feedback loops may cause ataxic breathing.