Open idea/brainstorming for an architecture to address the "long-ranging axon problem" in gradual brain replacement theory: separate local cortical replacement from tract-level continuity.
In A, macrocolumn-scale grafts are inserted into grey matter (geometry tbd), integrating vertically through cortical layers and horizontally with neighbouring grafts/native cortical tissue. At their basal surface, each graft interfaces with a Watanabe-style DAB-BMI (see Masa's "From Biological to Artificial Consciousness", ch. 6, pp. 143-153, or read our "Death is an Engineering Challenge" essay from last year for more info): a thin, double-sided two-dimensional electrode sheet inserted as a slice into directionally organised white-matter fibres, including U-fibres and longer projection tracts.
In B, the DAB-BMI preserves access to long-ranging axonal input/output channels that would otherwise be severed or left unmapped during gradual replacement. In C, the interface is shown as a tract-aligned, biomaterial-coated sheet placed between cut axonal bundle faces, allowing axon tips on both sides to reconnect near electrode sites