Figures and data
Kernel density distributions of voxel-wise coefficients of variation (CV = SD/|mean| across participants) for CBF, CBV, T2*, R2′, CMRO2, and BOLD.
Left and middle panels show CV distributions under baseline [control task] and task [calculation] conditions, respectively. Right panel shows CV distributions of percent signal change (PSC) estimates.
A Cortical surface maps showing the mean change in BOLD signal (ΔBOLD) across participants for all voxels included in the BOLD activation mask. Warm colors (red–yellow) indicate positive ΔBOLD values, whereas cool colors (blue) indicate negative ΔBOLD values. The color bar represents mean ΔBOLD (percent signal change). B Histogram of voxel-wise sign concordance rates across participants within the BOLD activation mask. The concordance rate reflects the proportion of participants showing the same sign (positive or negative) of ΔBOLD and ΔCMRO2 at a given voxel. Vertical dashed lines denote q(FDR)<0.05 significance thresholds for classifying voxels as discordant (sign concordance below chance) or concordant (sign concordance above chance). The numbers above the dashed lines indicate the number of voxels falling beyond each threshold.
A Relationship between median task-evoked changes in cerebral blood flow (ΔCBF) and cerebral metabolic rate of oxygen (ΔCMRO2) across all voxels showing statistically significant ΔBOLD responses. Voxels with statistically reliable ΔCMRO2 are color-coded by ΔBOLD sign and magnitude, whereas voxels with non-significant ΔCMRO2 are shown in light orange. The dashed diagonal indicates equal relative changes in CBF and CMRO2; voxels above the diagonal for negative ΔCMRO2 and below the diagonal for positive ΔCMRO2 correspond to an n-ratio (ΔCBF/ΔCMRO2) < 1. B Distribution of voxels within the BOLD activation mask by CMRO2 reliability and sign concordance. The top bar shows all voxels with significant ΔBOLD responses (n = 19,190), partitioned into voxels with no significant ΔCMRO2 effect (77.2%), concordant voxels (17.4%), and discordant voxels (5.4%). The middle bar shows voxels with positive ΔBOLD, of which 26.0% were classified as concordant, 0.4% as discordant, and 73.6% showed no significant ΔCMRO2 effect. The bottom bar shows voxels with negative ΔBOLD, of which 1.7% were concordant, 14.6% discordant, and 83.7% showed no significant ΔCMRO2 effect. Bar lengths indicate the number of voxels in each category. C Cortical surface maps illustrating the spatial distribution of voxel classifications shown in (B). Left panels display voxels with positive ΔBOLD; right panels display voxels with negative ΔBOLD. Colors correspond to concordant, discordant, and CMRO2 not reliable classifications.
