An intercept and two direction interactions reproduced context contrasts in ds004562 v1.0.0 erasing designs under the stated mappings

We tested whether the erasing design in OpenNeuro ds004562 version 1.0.0 can separate an additive context response from joint direction responses. An intercept and two functions of intended cursor and hand direction reproduced both context contrasts exactly. The identity held for all 11,730 erasing records in 46 archived event tables from 23 people. It also held in the second-day scope without sub-16. Direction main effects had rank 7. Context contrasts or the two direction interactions increased rank to 9. Including both sets gave rank 9 with 11 columns. A linear decoder using only the synthetic direction features classified all 240 held-out conditions in 120 reconstructed splits. This is a constructed example, not measured brain accuracy. A proposed eight-direction design added four diagonal directions. It made both context contrasts estimable under an additive context model with arbitrary joint direction-pair effects. Independent checks passed. Fresh source retrieval reproduced 14 numerical files byte for byte. The package preserves fixed source files, hashes, exact matrices, proof, code, results, and instructions. The proof uses intended directions inferred from the stated mappings. It does not establish absence of context representations in the brain.

motor adaptation · neural decoding · design identifiability · direction interactions · OpenNeuro ds004562