| Coma & Chronic Disorders of Consciousness  

Transcutaneous auricular vagal nerve stimulation and disorders of consciousness: a hypothesis for mechanisms of action

The Vagal Cortical Pathways model aims to explain possible mechanisms for the action of transcutaneous auricular vagal nerve stimulation to promote consciousness recovery, describing four pathways and six different mechanisms of action.

Transcutaneous auricular vagal nerve stimulation (taVNS) has recently been explored as a therapy for patients with disorders of consciousness and has shown promising results. However, the role of taVNS in consciousness recovery is not clear.

Therefore, we here propose the Vagal Cortical Pathways model based on consciousness recovery processes and taVNS mechanisms. This model highlights four consecutive pathways (A. Lower brainstem activation, B. Upper brainstem activation, C. Norepinephrine pathway, and D. Serotonin pathway) likely to have an impact on brain-injured patients.

Additionally, we suggest six different mechanisms of action: 1. Activation of the ascending reticular activating system; 2. Activation of the thalamus; 3. Re-establishment of the cortico-striatal-thalamic-cortical loop; 4. Promotion of negative connectivity between external and default mode networks by the activation of the salience network; 5. Increase in  activity and connectivity within the external network through the norepinephrine pathway; and 6. Increase in activity within the default mode network through the serotonin pathway. This model aims to explain the potential therapeutic effects that taVNS has on brain activity in the process of consciousness recovery.


Key Points:

  • Vagal nerve stimulation is a promising therapeutic option for patients with disorders of consciousness.
  • The Vagal Cortical Pathway is a new model designed to explain its action on brain function.
  • The model describes 4 consecutive pathways (lower and upper brainstem, norepinephrine and serotonin)
  • The model further proposes six different mechanisms of action for vagal nerve stimulation to improve recovery.



Briand M-M, Gosseries O, Staumont B, Laureys S and Thibaut A (2020) Transcutaneous Auricular Vagal Nerve Stimulation and Disorders of Consciousness: A Hypothesis for Mechanisms of Action. Front. Neurol. 11:933. doi: 10.3389/fneur.2020.00933