Data and code from: Towards optimizing target engagement in non-invasive trigeminal nerve stimulation: Anatomical characterization of the human trigeminal nerve

Microdissections quantified nerve circumference and depth relative to the skin surface. Histological analysis described the number of fascicles and fascicular tissue area. Nerve depths were incorporated into an illustrative finite element model to assess the effect of interface properties on activation of on- and off-target neural pathways.

Main Results: Cadaveric measurements, histological analyses, and imaging outline the depths, branching patterns, and fascicular organization within the trigeminal nerve branches. The SON was found to be significantly more superficial than the ION and MN with a higher nerve-to-connective tissue ratio compared to the MN. Our illustrative modeling demonstrated that depth was a driving factor for neural activation and sensitivity to skin impedance properties.

Significance: The SON presents the most accessible and anatomically favorable target for transcutaneous trigeminal nerve stimulation among the branches examined due to its superficial location. Consistent with our previous work, however, preferential activation of low-threshold nociceptors compared to nerve trunks may lead to treatment-limiting off-target side effects. These findings offer an anatomically informed framework to guide further modeling, electrode design, and in situ imaging of nerve branching patterns to better estimate activation of on- and off- target pathways.