Analysis of Temporal and Spatial Reliability of fMRI Signals in Emotion Regulation Task

Abstract

Recent research (Fröhner et al., 2019; Hajcak et al., 2017) raises serious concerns regarding the reliability of task-based functional magnetic resonance imaging (fMRI) metrics. Establishing the reliability of fMRI-based measurements is crucial for their clinical use, particularly in identifying meaningful biomarkers, tailoring personalized treatments, and guiding future research directions. Therefore, we evaluated three forms of reliability of a widely used emotion regulation fMRI task: split-half, test-retest, and spatial reliability. Our sample consisted of forty adult participants with no history of psychiatric or neurologic illness that underwent two fMRI scans 12 weeks apart. During both scans, participants completed an emotion regulation task instructing them to view neutral or distressing images from the International Affective Picture System (IAPS). In the (1) “Look Neutral” and the (2) “Look Negative” (i.e., Maintain) conditions, participants naturally viewed neutral or negative images, respectively, without attempting to change their emotional response. In the (3) “Reappraise Negative” participants were asked to change their thoughts about the image to alter their emotional response. Between each image, a fixation cross was shown. We extracted BOLD signal from a group of ROIs (10 ROIs) from a meta-analysis (Morawetz et al., 2020) of emotion regulation brain activation. From these ROIs, we then calculated split-half reliability at time 1, test-retest reliability (intraclass correlation between time 1 and 2), Euclidean distance between peak voxels (from time 1 and 2), and cluster overlap (dice coefficients). We found that split half reliability was highest for modelling Conditions alone, with the average falling in the “fair” range (average r=0.55, range= [-0.25, 0.82]). Both Condition-Fixation contrasts (average r =0.38, range= [-0.44, 0.74]) and the Condition-Look contrasts (average r =0.24, range= [-1.216, 0.616]) fell into the “poor” range (F (2,78) =13.66, p<0.001). Test-retest reliabilities showed a different pattern, such that the ICC for contrasts between active conditions – fixation were the highest (F(2,78)=20.51, p<0.001); average ICC = 0.40, range =[-0.26, 0.74]), followed by conditions alone (average ICC = 0.24, range =[-0.33, 0.54]), and active condition – look contrasts (average ICC = 0.07, range =[-0.31, 0.38]). We found higher spatial reliability when modelling Conditions alone, such that distances between peak activations during time 1 and 2 were shorter than for Contrasts (b = 2.01, SE = .37, t(704) = 5.45, p < 0.001). Reliability of the BOLD signal from task Conditions alone showed higher internal consistency across condition/contrast comparisons within a given scan whereas contrasts between active conditions – fixation had greatest test-retest reliability. Euclidean distance results show that conditions alone hold higher spatial consistency values at the group level from time 1 to time 2. These results suggest that future research using this task should be careful to select the most appropriate and reliable measures (conditions vs contrasts) based on their question of interest. Additionally, task-based fMRI researchers should consistently evaluate the psychometric properties of their data.No embargoAcademic Major: Psycholog