Because the outcome of the PLS analysis might vary with the valence of our materials, we conducted separate analyses for Negative and Neutral scenes. For Negative scenes, the first LV accounted for 76% and 79% of the covariance between intrusion control activations and behavioral measures of intrusion proportion and affect suppression within the frontoparietal retrieval suppression network and the MTL mask, respectively (p < 0.05). The first LV was significantly different from random noise as assessed by permutation testing (p < 0.05). For Neutral scenes, the first LV accounted for 73% and 68% of the covariance between behavioral measurements and the prefrontal retrieval suppression network and the MTL mask, respectively (p < 0.05). A second LV was not significant for either Negative or Neutral scenes.
B, Scatter plots present in suitable MFG demonstrating the partnership grabbed by PLS investigation between the upregulation (Intrusion ? Non-Intrusion) and you may behavioural results for Negative and Natural moments
The clear presence of a critical LV one makes up about a large part of the brand new covariance between invasion-handle activations and all of our very own behavioural procedures implies that particular voxels when you look at the prefrontal cortex and you may MTL try connected with mnemonic and/or affective command over offending memory. They don’t, however, establish how head activation relates to men and women steps. To allow for alot more obvious interpretation of one’s role of those voxels, we 2nd calculated “voxel salience” (new voxels that led to our very own key LV) and you can a mind get per participant (find Product and methods). A mind get indicates just how much certain participant expresses new multivariate spatial trend out-of relationship anywhere between intrusion handle activations and you may behavioral measures off mnemonic and affective manage caught because of the an enthusiastic LV.
For this reason, correlations anywhere between notice ratings and you may behavioral dimensions assist to select the new guidance together with fuel of matchmaking captured because of the a given LV (which means the latest related voxel salience more than one LV)
Critically, within the frontoparietal control network, we found that, for negative scenes, participants’ brain scores for the first LV correlated positively with their affect suppression scores (r = 0.60 p < 0.05, [0.35, 0.79] bootstrapped 95% CI) and negatively with intrusion proportion (r = ?0.79, p < 0.05, [?0.91, ?0.60] bootstrapped 95% CI; Fig. 5A). Importantly, this finding indicates that for those voxels having a positive salience, upregulation during Intrusions (vs Non-intrusions) negatively correlated with intrusion frequency (i.e., better mnemonic suppression), and additionally positively correlated with affect suppression score (i.e., better affective suppression) for Negative scenes (for an illustration of this pattern, see Fig. 5B). These patterns are inverted for voxels associated with a negative salience. Voxels within our retrieval suppression mask associated with a significantly positive salience (using a bootstrapping procedure; see Materials and Methods) were localized across the entire control network, including left and right MFG, dorsal portion of the anterior cingulate cortex, superior frontal medial gyrus, inferior frontal gyrus, insula, and inferior parietal cortex (Fig. 5A; Table 3). For Neutral scenes, participants' brain scores for the first LV also correlated negatively with intrusion proportion (r = ?0.72, p < 0.05, [?0.87, ?0.54] bootstrapped 95% CI) but, in contrast to findings with negative scenes, showed no significant correlation with their affect suppression scores (r = ?0.16, [?0.54, 0.19] bootstrapped 95% CI; Fig. 5A).
Outcome of the PLS analysis for both Negative and Neutral scenes (conducted within the retrieval suppression network; see Materials and Methods) between intrusion-related upregulation (Intrusion ? Non-Intrusion) and behavioral measures (intrusion proportion and affect suppression score). A, Voxels showing a significant pattern of brain/behavior correlations as revealed by the first (significant) LV were identified using a BSR threshold higher/lower than 1.96/?1.96, respectively (i.e., p < 0.05). Correlations between participants' brain scores and behavioral measures for the first significant LV are also reported in A. Error bars indicate bootstrapped 95% CI. Brain scores reflect the contribution of each participant to a given LV. The correlation between brain scores and behaviors thus reveals the meaning of the LV. These findings reveal voxels whose upregulation is associated with reduced intrusion frequency for both Negative and Neutral scenes and also with increased affect suppression score only in the case of Negative scenes (reduced negative affect for suppressed images). BSR maps were rendered on the top of the PALS human surface using Caret software (Van Essen et al., 2001) (RRID:SCR_006260).