Polyvagal Theory

Polyvagal Theory (gr. 'polus', “‘many’” + 'vagal', "'Vagus Nerve'") specifies two distinct branches of the vagus, or the 10th cranial nerve. Each branch originates in the medulla. The phylogenetically older branch originates in the dorsal motor nucleus (DMX), whereas the newer branch originates in the nucleus ambiguus (NA). Both branches provide inhibitory input to the viscera, including the heart. However, each does so in service of distinct evolutionary functions. The DMX branch is tasked with primary survival strategies, enacting defensive behaviors such as fighting, flighting, or freezing. The NA branch, only found in mammals, is used in modulating the fight/flight response towards the execution of social affiliation behaviors. University of Illinois at Chicago professor Stephen Porges is one of the father of the polyvagal theory.

Functional organization of the autonomic nervous system is thought to be phylogenetically hierarchical, with response strategies to threat dictated by the newest neural structures first, then falling back on older structures when a given response strategy fails. Therefore, polyvagal theory predicts that the NA branch will inhibit acceleratory sympathetic nervous system (SNS) input to the heart when attention and social engagement are adaptive, and withdraw this inhibitory influence when fighting or fleeing are adaptive.Beauchaine, T., Gatzke-Kopp, L., Mead, H., (2007). Polyvagal Theory and developmental psychopathology: Emotion dysregulation and conduct problems from preschool to adolescence. "Biological Psychology, 74", 174-184.]

Psychological Implications

Beauchaine "et al". have argued that an under-responsive central reward system coupled with deficient vagal modulation of emotion leads to sensation-seeking and aggressive behaviors characteristic of externalizing disorders, such as conduct disorder and delinquency, while an over-responsive central inhibition system coupled with deficient vagal modulation of emotion leads to withdrawal behaviors characteristic of internalizing disorders, such as anxiety and panic.

ee also

* Emotional dysregulation
* Fight-or-flight response
* Autonomic Nervous System

External links

* [http://www.wam.umd.edu/~sporges/polyvag.htm The Polyvagal Theory]
* [http://stanleyrosenberg.com/english/articles/polyvagal_theory The polyvagal theory: phylogenetic substrates of a social nervous system]
* [http://www.stephenporges.info/index.php The Stephen Porges Info Site] The originator of the Polyvagal theory
* [http://www.nexuspub.com/articles/2006/interview_ma.htm "How your nervous system sabotages your ability to relate"] An Interview with Stephen Porges Ph.D. by Nexus magazine (March/April 2006)

References