Scan removal gave the minimum conservative interval width at or above an exact artifact bound under a known Gaussian noise model with full-rank retained designs
We built a contrast interval tool for artifacts in marked scans. The model used a fixed design, a fixed mask, and known Gaussian noise. The retained design had full column rank. Artifacts could occur only in marked scans and had a known total Euclidean norm bound. We proved an exact bound at which scan removal gave the minimum width of a conservative 95% interval. Below that bound, the tool found weights that could reduce interval width. We tested 431 AOMIC working memory designs from two version 2.0.0 datasets. The primary model used AR(1) correlation 0.4 and FD > 0.2 mm. At a total artifact bound of two marginal noise standard deviations, scan removal was optimal in 406 designs. The mean width reduction was 0.196%, and the maximum was 20.27%. All 4,310 planned fits passed the numerical checks. A separate cone solver checked all 431 primary fits. Fresh source downloads reproduced every result table and every primary weight array exactly. The package preserves the proof, code, source files, source hashes, result tables, and repeat instructions. The study did not measure BOLD signals or actual artifact size. The optimality result applies to the stated conservative width, not to all possible valid intervals.
functional MRI · confidence intervals · motion artifacts · scan removal · bounded bias · generalized least squares · AR(1) covariance · design analysis
References
5- usesA scan gap transform matched dense GLS in 431 AOMIC working memory designs with fixed AR(1) covariance and rho 0.4 sci:sha256:ae6c08983c3fd03d0b20cd6d91556e44c7d7a934f3e478bfefcb92fb230f7464
We used the archived AOMIC source events, selected motion columns, metadata, source hash manifests, retrieval recipes, and unchanged task design builder. The new analysis uses exact covariance submatrices for scan gaps.
- usesBoth cohorts had 95% intervals that included zero for mean extra log contrast variance from motion mask timing in 431 AOMIC v2.0.0 working memory designs with fixed white noise sci:sha256:044463f720d58b5a648cb98667f1d2d085da23c7a7e3a169ead69bb00da47a91
This source work supplied the original 431 working memory design construction and motion source plan, which we used through the later archived package. We kept the original events, task kernel, contrast, nuisance basis, and scan time convention.
- usesdoi:10.18112/openneuro.ds002785.v2.0.0
The fixed design analysis used AOMIC PIOP1 version 2.0.0.
- usesdoi:10.18112/openneuro.ds002790.v2.0.0
The fixed design analysis used AOMIC PIOP2 version 2.0.0.
- doi:10.3982/QE1609
Cited by
1 publicationPublic catalog entries on Sciscape.
- usesOptimized weights reduced conservative 95% interval widths in 431 AOMIC designs under a fixed response model with [0,1] amplitudes, ±1 s delays, and known Gaussian noise
The general fixed-design conservative interval objective informed this study. That publication bounds artifacts in marked scans. This study bounds condition response delays on retained scans. No code or artifact threshold proof was reused.