The vagus nerve as a neurovisceral interface: a comprehensive review

Figures

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  Figure 1. Anatomy of the sensory vagus nerve. It depicts the vagus nerve and its major distribution from the medulla oblongata through the head and neck into the thorax and abdomen, showing branches to the ear, larynx, heart, lungs, esophagus, liver, stomach, intestine, and pancreas.

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  Figure 2. Structural and functional organization of the heart-brain circuit. The Heart-Brain circuit functions as an integrated hub where sympathetic and vagal pathways converge to pre-process cardiac signals. Spinal afferents (dense in the anterior wall of the left ventricle) and vagal afferents (dense in the infero-posterior wall of the left ventricle) relay to the central nervous system, while the intrinsic cardiac nervous system (ICNS) serves as a “little brain” within the epicardial plexus to fine-tune autonomic output. The RA and LA means the right and left atrium. This figure is modified from Mohanta et al. (2023). Source: Figure 3. License: American Heart Association (permission not yet obtained). Material: Adapted (redrawn with additional original content).

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  Figure 3. Mechanisms of gut-brain communication via the vagus nerve. The vagus nerve serves as a bidirectional conduit linking the gut to the brain, modulating systemic metabolism, inflammation, and mental health. Within the intestinal mucosa, enteroendocrine cells (EECs) respond to luminal stimuli and signals from the gut microbiota by releasing mediators such as serotonin and glutamate. These substances communicate with neighboring vagal afferent endings through paracrine, rather than synaptic, mechanisms, thereby contributing to gut–brain signaling and central autonomic responses. The figure is modified from Cryan and Dinan (2012). Source: Figure 1. License: Springer Nature (permission not yet obtained). Material: Adapted (redrawn with additional original content).