Article 16
The 2D nerve cross-section sandbox (electrodes, fields, constraints)
A 2D cross-section model is the highest-leverage starting point for the simulation roadmap. It is simple enough to run in the browser and intuitive enough to teach. It also captures the first-order truth: in many regimes, selectivity and recruitment are geometry problems.
What the sandbox should let you do
At minimum:
- choose a nerve cross-section with fascicle layout,
- place electrode geometries (cuff, FINE-like, intrafascicular, “regenerative zone”),
- set stimulation parameters,
- see field/recruitment proxies,
- export/import settings.
What we can measure (early proxies)
We won’t claim perfect biophysics at v1. But we can compute useful proxies:
- distance-weighted field magnitude within fascicles,
- overlap metrics (how selectively are we targeting one fascicle vs others?),
- threshold-like contours (relative, not absolute),
- safety bounds (charge per phase and charge density estimates).
Why 2D is not “fake”
2D cross-sections are a legitimate way to build intuition and to test design strategies quickly. As we add complexity later, the 2D sandbox becomes the conceptual map.
References (starter)
- Basic nerve anatomy overview: https://en.wikipedia.org/wiki/Peripheral_nervous_system