The Ear as a Polyvagal Portal: Neuro-auricular modulation in consideration of 3 developmental response systems

The Ear as a Polyvagal Portal: Neuro-auricular modulation in consideration of 3 developmental response systems

Portal to the wandering nerve:

Did you know that you can directly access neural pathways of the body via reflex zones on the outer ear to help clients/patients move toward healing with greater ease? Neuroscientists are using the microsystem of the outer ear to transcutaneously access the major nerve branches of the body, and research into neuro-auricular modulation has grown in depth and breadth in the past two decades.[1-8] More specifically, the therapeutic use of transcutaneous auricular vagus nerve stimulation (taVNS)[9-10] has gained attention across various fields of healthcare: by psychologists, neuropsychiatrists, biomedical device manufacturers, physicians and more.[11] The vagus nerve sparked interest in the field of psychology (and other fields) since the explosion of Polyvagal Theory presented by Dr. Stephen Porges — especially in support of the continuing science evolving around safety and trauma.*

Porges, the founding director of the Traumatic Stress Research Consortium of the Kinsey Institute at Indiana University, opened the door to a deeper understanding of multiple aspects (poly-aspects) of the vagus nerve, also known as the wandering nerve because it connects with so many aspects of the body. The vagus nerve is part of the autonomic nervous system (ANS) and stretches from the brainstem to the colon affecting many critical physiological/metabolic processes including heart rate, digestion, and our reaction to the world around us. Polyvagal Theory states that our reaction to the world around us is the result three behavioral states respectively related to three branches of the ANS (two of which are vagal). These three states have their roots in the following three developmental strategies (phylogenetic response systems).[12,16]

  1. Parasympathetic I/Dorsal Vagal State involved in the shut down mode (e.g. hypo-arousal or low-freeze state).[12,13] This is the most primal phylogenetic response — a nervous system response related to the unmyelinated vagus of the parasympathetic nervous system coming from the Dorsal Motor Nucleus (DNS).[12] The complete shut down mode often dominates in individuals who are chronically neglected or abused.[14] 
  2. Sympathetic State involved in the fight-or-flight mode (e.g. hyper-arousal or high-freeze state).[12-15] The non-vagal high-freeze response of fight-or-flight mode generally dominates in individuals who have been acutely traumatized, usually by an individual event.[14] 
  3. Parasympathetic II/Ventral Vagal State involved in the social engagement mode (optimal arousal or relaxed state)[12,13] This is the most developed phylogenetic response — a nervous system response related to the myelinated pathway (myelin provides the nerve electrical insulation enabling greater specificity and speed in signal transmission) conveying respiratory rhythm to the heart, resulting in a rhythmic oscillation in the heart rate at the frequency of spontaneous breathing.[12] The Ventral Vagal Complex has motor (efferent) and sensory (afferent) aspects related to the Nucleus Ambiguous (NA) and Nucleus Tractus Solitarius (NTS) respectively.

Dr. Greg Lewis, director of the Socioneural Physiology Laboratory at Indiana University’s Kinsey Institute, highlights a significant point for understanding, “the 3 states or branches are of the ANS [they are not all vagal]. The vagus nerve (cranial nerve X) is only involved in the parasympathetic branch of the ANS, and thus the most recent adaptation, Parasympathetic II, and the oldest, Parasympathetic I, branches of the ANS. The sympathetic branch of the ANS does not have any vagal pathway. It, instead, is inhibited by the Parasympathetic II — and in turn, these sympathetic systems inhibit Parasympathetic I, the old parasympathetic systems.”

Polyvagal Theory helps provide a framework for understanding that the mammalian nervous system not only responds to environmental demands and perceived stresses/threats, but it will also rapidly reorganize, in a predictable order, to different neural-mediated states. The phylogenetically-based hierarchy of autonomic states, as well as the specific triggers that cause a dissolution of this hierarchy, provide a new way of investigating atypical behavior.[16] Polyvagal Theory offers insight for clinical applications of respective neuro-auricular reflex zones on the outer ear related to these autonomic states.


How to prime the nervous system to overcome challenges in therapy via the auricular microsystem:

Training in neuro-auricular modulation for mental health professionals interested in applying direct access to the poly-aspects of the vagus nerve is available at the Canadian Institute of Auricular Medicine (CIAM). In an EMDR related course, part of a bundle of INTRO courses on Auricular Methods in Psychology, mental health professionals apply neuromodulation techniques as a window to the brain — and help prime the nervous system to overcome challenges with dual attention, resourcing and processing.

CIAM | Editor’s note: The Canadian Institute of Auricular Medicine, a leader of continuing education in the field of applied neuro-auricular modulation for assessment and treatment, is the only program of its kind to connect its CORE training to the respective challenges in specific fields of healthcare and wellness practice — including psychotherapy:


*Footnote: The continuing science around safety and trauma is exemplified through projects such as the collaboration between Spencer Psychology and the Traumatic Stress Research Consortium at Indiana University’s Kinsey Institute


[1] Badran B, Dowdle L, Mithoefer O, Austelle C, McTeague L, George M. Neurophysiologic effects of transcutaneous auricular vagus nerve stimulation (taVNS) via electrical stimulation of the tragus: A concurrent taVNS/fMRI study and review. Brain Stimulation. 2017; 11(3):492-500. DOI:

[2] Hays SA. Enhancing Rehabilitative Therapies with Vagus Nerve Stimulation. Neurotherapeutics. 2016;13(2):382-394. doi:10.1007/s13311-015-0417-z

[3] Edgerton R., Gad P. Spinal Cord Injury: Is the vagus nerve our neural connectome? eLife 2018;7:e35592 DOI: 10.7554/eLife.35592

[4] Shiozawa P, Silva ME, Carvalho TC, et al. Transcutaneous vagus and trigeminal nerve stimulation for neuropsychiatric disorders: a systematic review. Arq Neuropsiquiatr. 2014; 72: 542-7.

[5] Badran BW, Brown JC, Dowdle LT, et al. Tragus or cymba conchae? Investigating the anatomical foundation of transcutaneous auricular vagus nerve stimulation (taVNS). Brain Stimul. 2018;11(4):947-948. doi:10.1016/j.brs.2018.06.003 

[6] Kong J, Fang J, Park J, et al. Treating Depression with Transcutaneous Auricular Vagus Nerve Stimulation: State of the Art and Future Perspectives. Front Psychiatry. 2018; 9: 20.

[7] Redgrave JN, Moore L, Oyekunle T, et al. Transcutaneous Auricular Vagus Nerve Stimulation with Concurrent Upper Limb Repetitive Task Practice for Poststroke Motor Recovery: A Pilot Study. J Stroke Cerebrovasc Dis. 2018; 27: 1998-2005.

[8] Fang J, Rong P, Hong Y, Fan Y, Liu J, Wang H, Zhang G, Chen X, Shi S, Wang L, Liu R, Hwang J, Li Z, Tao J, Wang Y, Zhu B, Kong J. Transcutaneous Vagus Nerve Stimulation Modulates Default Mode Network in Major Depressive Disorder. Biological Psychiatry. 2016 Feb 15;79(4):266-73. 

[9] McLeod M. Advanced taVNS Conference Archived Presentations: Advanced Transcutaneous Auricular Vagus Nerve Stimulation.College of Health Professions, Medical University of South Carolina website. 2020. Accessed November 2021.

[10] Biksom M. CCNY Neural Engineering Group: Selected Publications of Marom Biksom, PhD. The Neural Engineering Group at The City College of New York website. 2021. Accessed November 2021.

[11] Hoffmann D. FDA Clearances of Auricular, Cranial and Other Forms of Neuromodulation. Ear to the Ground: News and ideas that integrate auricular from the Canadian Institute of Auricular Medicine website. January 31, 2021. Accessed November 16, 2021.

[12] Porges SW. The polyvagal theory: new insights into adaptive reactions of the autonomic nervous system. Cleve Clin J Med. 2009;76 Suppl 2(Suppl 2):S86-S90. doi:10.3949/ccjm.76.s2.17]

[13] Siegel DJ (1999) The Developing Mind. New York: Guilford.

[14] Levine, P. (2010). In an unspoken voice: How the body releases trauma and restores goodness. Berkeley, California: North Atlantic Books. 102.

[15] Godoy L., Rossignoli, M., Delfino-Pereira, P., Garcia-Cairasco, N., de Lima Umeoka, E. A Comprehensive Overview on Stress Neurobiology: Basic Concepts and Clinical Implications. Front. Behav. Neurosci. 2018;12(127):3-4.

[16] Porges, S. W. (2001). The polyvagal theory: phylogenetic substrates of a social nervous system. International journal of psychophysiology42(2), 123-146.


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