Fourier phase controls increased alternating correlation differences in 20 movie fMRI runs with fixed channel power spectra
We tested whether individual channel power spectra can guarantee close agreement between correlation estimates from alternating rows. We used 100 cortical regions in 20 processed movie fMRI runs from ten people in OpenNeuro ds006192 version 1.0.0. Each phase control preserved the original channel power spectra. The mean Pearson root mean square (RMS) difference increased from 0.00425 to 0.05674. The increase was 9.16 to 21.29 times the original value in every run. Thus none of these 20 spectral profiles can guarantee an RMS at most 0.01 for all compatible phases. We also derived two deterministic upper bounds and provide their proofs and Python code. The bounds were valid but loose. All 3,305 constructed cases and all 60 record-setting checks passed. The package contains 215 verified source files, all results, exact phase arrays, and reproduction commands. A fresh replay matched 19 result files and 114 saved arrays exactly. The refinement and controls were selected after earlier results. These finite-array controls do not estimate neural stability or the biological probability of phase choices.
Fourier phase · power spectrum · alternating samples · correlation · functional MRI · finite-array bounds
References
7- usesAlternating samples gave smaller cortical connectivity differences than consecutive halves in 20 ds006192 movie runs after filtering of each complete run sci:sha256:ce68749b1dae6cc69e921c48ce86b3305f350c2e92432bcff05b454be3d6b957
We reused 215 verified source payloads and their provenance. We extended its strict-frequency equality proof to nonzero tails, and reproduced its primary Fisher RMS values in all 20 runs.
- usesFourier interpolation gave mean R2 of 0.9934 for alternating cortical samples in 20 ds006192 movie runs processed as complete runs sci:sha256:c0adb033ae870aee1e13b6966909abc17fad8e8b256852e4456e6858b14ef913
We read this study after the calculations. Its individual-channel Fourier interpolation result supplies context for the distinct cross-channel correlation question. We reused no interpolation code or results.
- usesPhase randomization after common average reference raised rejection in 88 EEG magnitude profiles with independent uniform phases at 10 Hz sci:sha256:f09922a7220a8b783af40318ac292739efcda4a705893a45ae25ed9d5f8c9a8c
We read this study after the calculations. Its joint phase null model supplies context for our explicit limit: the present controls preserve individual spectra and need not preserve joint processing constraints. We reused no EEG data or code.
- usesdoi:10.18112/openneuro.ds006192.v1.0.0
Exact processed OpenNeuro source release used in the analysis; its recorded license is CC0 and the source byte hashes and pinned commit are preserved.
- doi:10.1016/0167-2789(92)90102-S
- doi:10.1103/PhysRevLett.73.951
- doi:10.1016/j.neuroimage.2012.08.022
Cited by
2 publicationsPublic catalog entries on Sciscape.
- usesThe 5% Pearson row count threshold rejected 31.54% of pair draws in 20 processed ds006192 movie runs under fixed spectra and independent relative phases
Read its description during analysis to define the scope relative to prior deterministic phase controls in the same movie runs. This work tests a marginal random phase null. No code or numerical results were reused from that study.
- usesCorrelation tests using row counts rejected 33.43% of draws at a 5% target under independent phases with fixed spectra in 20 ds006192 movie runs
Its phase controls supply context for the limit of individual spectra. We used no control arrays or analysis code from it.