Neural Noise- Functional anatomy of autonomic nerve fascicles is poorly understood; organotopic organization has been suggested in animal vagus nerve.1
- In human cadaver vagus nerves, microCT segmentation and histology of thoracic branches (cardiac, recurrent laryngeal, pulmonary) characterize fascicular anatomy relevant to targeted cardiac stimulation.1 1
Weekly enrichment (2026-07-20)
- This is a pilot anatomical study: both left and right vagus nerves were dissected from 5 human cadavers (n = 10 nerves, 5 left and 5 right) with cardiac, recurrent laryngeal, and pulmonary branches preserved; microCT fascicle tracing was performed on 5 nerves (3 left, 2 right) and histology/immunohistochemistry on all 10.2
- MicroCT used Lugol’s iodine staining (~120 h) and a Nikon XT H 225 scanner at 7 μm isotropic voxel resolution, with fascicles segmented and traced in Vesselucida 360 and validated against histology at the level of the stimulation cuff and along the trunk.2
- Cardiac, pulmonary, and recurrent laryngeal fascicles preserved partial organotopic organization near their entry points but merged further along the nerve; in left nerves cardiac and pulmonary fascicles merged while recurrent laryngeal fascicles stayed separate, whereas in right nerves cardiac fascicles merged with both pulmonary and recurrent laryngeal groups.2
- Right vagus nerves had a larger diameter and more fascicles, with counts varying along the length reflecting anastomoses (merging and splitting events).2
- Critically, the superior cardiac branch on both sides remained distinct near the typical VNS cuff site, supporting the feasibility of selective cardiac neuromodulation.2
- The work builds on Thompson et al. (2023), which used fast neural electrical impedance tomography (fnEIT), selective stimulation, and microCT to demonstrate organotopic cardiac, pulmonary, and laryngeal fascicles in the porcine mid-cervical vagus nerve (N = 4).3
- In the porcine model, cardiac afferent and efferent fibers were spatially separated by 179 ± 55° (microCT) and 200 ± 137° (selective VNS) across the nerve cross-section (p < 0.05), with roughly 47% of fascicles afferent/sensory and 36% efferent/motor, enabling scalable heart-rate modulation without triggering afferent reflexes.4
- Clinical/BCI implications: fascicle-level maps support spatially selective VNS that could reduce off-target effects and extend therapy beyond currently approved epilepsy and depression toward cardiac indications such as myocardial infarction, heart failure, and atrial fibrillation; the authors note the human results are preliminary, constrained by COVID-era access and by ChAT immunohistochemistry that could not be optimized on human tissue.2 4