January 2, 2014
The autonomic nervous system is traditionally described as consisting of two antagonistic and balanced branches, the sympathetic and the parasympathetic system. The sympathetic system or the “fight or flight” arousal system kicks into gear when we perceive threats. When that happens your blood pressure increases, your muscles tense, your heart beats faster, and digestion slows down. The parasympathetic system has been thought to be responsible for “rest-and-digest”. Say it is a nice, sunny day and you decide to relax and take in the nice weather in a comfortable chair. In that situation your “rest and digest” response should cause your blood pressure to decrease, pulse rate to slow, and digestion to start.
Something else, however, is happening in this video. In the video the possum immobilizes and looks dead, but it’s not engaging in a voluntary behavior, or a ‘fight or flight’ or ‘rest and digest’ response. It is using a defense mechanism called immobilization which causes a drastic slowing of the metabolic system.
Read more: Immobilized by ME/CFS and/or FM? The Polyvagal Theory, the ANS and Movement Restriction http://www.cortjohnson.org/blog/2014...ervous-system/