The concept of bilateral and asymmetrical postural extension patterns is routed in the science and methodology of the Postural Restoration Institute. Please refer to the following resources and references for more information on these concepts.
The ultimate place to gather information on postural extension patterns: Postural Restoration Institute
Correlating the ANS and PRI
Blog by Peter Nelson, undergraduate student correlating the autonomic nervous system and the Postural Restoration Institute approach using The Polyvagal Theory by Stephen Porges: 1. http://ihperformance.com/2014/10/an-introduction-to-the-postural-restoration-institute/ and 2. http://ihperformance.com/2014/11/an-introduction-to-the-postural-restoration-institute-part-2-biochemical-physiological-responses-to-neurological-states/
Essay by Bill Hartman, PT tying together PRI and the ANS: https://www.posturalrestoration.com/community/post/1734/pri-conversations-bill-hartman?id=1734
General PRI concepts for starting out
1 Hour Podcast on by Michael Mullin, ATC, LAT, PTA, PRC: http://thefitcast.com/episode-
Excellent and Entertaining Reviews on PRI Courses
Blog by Zac Cupples, PT, DPT, OCS, CSCS, FMSC: http://zaccupples.com/category/pri/ : Recommend reading Postural Respiration or Myokinetic Restoration posts first.
Blog by Lance Goyke, CSCS: http://www.lancegoyke.com/?s=pri