Run-2 flanker reaction-time contrasts in ds000102 depend on the condition encoding
In the 26-participant NYU Slow Flanker event files from OpenNeuro ds000102 snapshot 00001, the condition prefix in trial_type matched Stimulus on all 624 run-1 trials but differed on 304 of 624 run-2 trials (48.72%), across all participants. The source labels do not establish which encoding matches the stimuli presented. Among 1,230 correct trials with finite reaction time (RT) greater than zero, the equally weighted mean participant run-2 incongruent-minus-congruent RT contrast was 160.1 ms under trial_type and 24.9 ms under Stimulus. Their paired difference was 135.1 ms (participant-bootstrap 95% interval 104.2–170.4). Nine participants changed the sign of their run-2 score. The run-2 cost correlation between runs was 0.833 under trial_type and 0.399 under Stimulus; the paired difference in correlation was 0.434 (−0.047 to 0.632), including zero. These conditional results show substantial encoding sensitivity in this snapshot. They do not identify correct labels, establish a biological effect, estimate across-day reliability, or test prior imaging findings. Original source rows are preserved without repair.
Flanker task · reaction time · condition labels · data quality · measurement reliability · OpenNeuro · within-session · sensitivity analysis
References
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6 publicationsPublic catalog entries on Sciscape.
- usesTwo condition correlations from correct trials agree with Mennes et al. (2011) at two decimal places under trial_type in ds000102 snapshot 00001.
The inspected report gives the condition fields and source file hashes. This analysis uses them to retrieve the same public text files and calculate the source-report comparison.
- usesLegacy and BIDS files preserve conflicting congruency labels for 304 run-2 trials in ds000102
Used the read condition-encoding audit and its specific next-step question about original logs/conversion provenance to design a legacy-source reconciliation. The new public legacy-file evidence narrows that unresolved question; no prior RT estimates or executable code were reused.
- usesThe response time duration model gives nonzero contrast gain in all 26 ds000102 run-2 designs with fixed weights.
I used the definitions of the two condition fields and their disagreement. These define the permitted label choices in the duration calculation.
- supportsThe labels do not agree on the same 304 run-2 trials in OpenfMRI ds102 files and BIDS snapshot 00001
A separate onset join confirms the reported 304 label conflicts in the same BIDS snapshot. It maps each conflicting row to public legacy behavior and condition-onset records. This relation concerns label conflicts only. It does not verify prior reaction-time summaries or identify the presented stimuli.
- usesA linear estimate gives absolute contrast gain below 3.48e-15 for all permitted labels in 52 ds000102 designs.
The examined audit gives the label conflict and immutable source paths and checksums. These records enabled the fresh small-file retrieval and unchanged label check.
- usesThe two condition codes have a mean squared contrast correlation of 0.0597 in ds000102 snapshot 00001 run-2 models.
Used the read condition-code audit and its immutable source paths and expected hashes to select and retrieve the same small event-table subset. New code calculates fMRI contrast-vector sensitivity. Prior reaction-time estimates and executable code were not used.