Problem: The three circuits are organized and respond to challenges in a phylogenetically determined hierarchy consistent with the Jacksonian principle of dissolution. Jackson proposed that in PORGES Page 3 Cleve Clin J Med. Author manuscript; available in PMC 2011 June 5. NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript the brain, higher (ie, phylogenetically newer) neural circuits inhibit lower (ie, phylogenetically older) neural circuits and "when the higher are suddenly rendered functionless, the lower rise in activity."18 Although Jackson proposed dissolution to explain changes in brain function due to damage and illness, the polyvagal theory proposes a similar phylogenetically ordered hierarchical model to describe the sequence of autonomic response strategies to challenges. Need Assignment Help?