Auricular branch of the vagus nerve (ABVN) (ABVN)

The auricular branch of the vagus nerve (ABVN), commonly referred to as Arnold's nerve, is a specialized sensory branch of the tenth cranial nerve that provides cutaneous innervation to the concha and external auditory canal (Butt et al., 2020). It represents a significant therapeutic target in bioelectronic medicine because it is the only peripheral vagal branch accessible for non-invasive stimulation, providing a direct neural pathway to the brainstem (Badran et al., 2018). Afferent fibers within the ABVN project primarily to the nucleus tractus solitarius (NTS), which serves as a relay station to modulate autonomic, emotional, and inflammatory processes via the locus coeruleus and the cholinergic anti-inflammatory pathway (Yakunina et al., 2017). Clinically, transcutaneous auricular vagus nerve stimulation (taVNS) is utilized to treat refractory epilepsy and depression, and is being investigated for its efficacy in managing chronic pain, migraines, and systemic inflammatory disorders (StatPearls, 2023). While the nerve is primarily a target for electrical modulation, its activity can be influenced by pharmacological agents that alter sensory fiber excitability or synaptic transmission (Farmer et al., 2021).

Other names

Arnold's nerveAlderman's nerveAuricular vagus nerve afferent fibersRamus auricularis nervi vagi

The primary mechanism involves the electrical activation of myelinated Aβ afferent fibers, which transmit signals to the nucleus tractus solitarius (NTS) in the medulla (Butt et al., 2020). From the NTS, signals are relayed to the locus coeruleus and raphe nuclei, leading to the modulation of norepinephrine and serotonin levels throughout the central nervous system (Yakunina et al., 2017). Additionally, stimulation activates the cholinergic anti-inflammatory pathway, which inhibits the release of pro-inflammatory cytokines via the splenic nerve and α7 nicotinic acetylcholine receptors on macrophages (Badran et al., 2018).