Enhancing Agency in Individuals with Depressive Symptoms: The Roles of Effort, Outcome Valence, and Its Underlying Cognitive Mechanisms and Neural Basis

Abstract

Background: Agency, a sense of control over one's actions and outcomes, is crucial for recovery from depressive symptoms. However, the mechanisms that enhance agency in individuals with depressive symptoms remain poorly understood. This study endeavors to elucidate these fundamental processes.

Materials and methods: We recruited 52 participants exhibiting depressive symptoms to participate in a novel Judgment of Agency (JoA) task. This task was structured with a 3 (effort: high load, medium load, low load) × 2 (outcome: win, miss) within-subject design to assess the impact of effort and outcome valence on agency. Throughout the task, we utilized functional near-infrared spectroscopy (fNIRS) to explore the neural mechanisms underlying agency. Furthermore, we conducted a randomized, sham-controlled, pre-post-test trial involving intermittent theta-burst stimulation (iTBS) targeted at the left dorsolateral prefrontal cortex (DLPFC) to investigate its potential to enhance agency. Participants were randomly allocated to either an active iTBS group or a sham group, with each receiving a single session of stimulation (600 pulses). The JoA task was conducted both before and after the stimulation.

Results: Effort significantly influenced agency in individuals with depressive symptoms, with this effect being moderated by the outcomes' valences. Agency was positively correlated with self-efficacy (r = 0.28, P < 0.05) when goals were achieved with effort, and with anxiety severity (r = 0.29, P < 0.05) when goals were not achieved. Additionally, it was associated with the activation of several frontal brain regions (all P values < 0.01), including the left DLPFC, right premotor and supplementary motor areas, and the left inferior frontal gyrus (IFG). Application of iTBS over the left DLPFC significantly enhanced self-attributed agency, particularly when the outcomes were achieved under conditions of low-load effort.

Conclusions: Our study highlights the critical role of effort in enhancing agency for individuals with depressive symptoms, with iTBS applied to the left DLPFC showing potential to enhance agency postgoal achievement. Moreover, the activation of the left IFG and the presence of anxiety are associated with maladaptive self-attributed agency, offering potential targets for therapeutic intervention.

Figure 1

Outline of experimental settings. (a) Flowchart of the experiment. BDI-II = Beck Depression Inventory-II, GAD-7 = Generalized Anxiety Disorder-7, DHS = Dispositional Hope Scale, GSES = General Self-efficacy Scale. (b) Timeline of an example trial of three-load effort blocks in the judgment of agency task (golden miner task). (c) Sources (pink), channels (green with channel numbers), and detectors (blue) were used in the functional near-infrared spectroscopy (fNIRS) recording. (d) Intermittent theta burst stimulation (iTBS) protocol.

Figure 2

Manipulation test of effort. (a) Self-reported engagement in the three-load effort condition. (b) Self-reported liking of the three-load effort condition. ⁣^∗∗P < 0.01, ⁣^∗∗∗P < 0.001.

Figure 3

The effect of effort and outcome on judgment of agency and behavioral correlation analysis. (a) The interaction effects of effort loads and outcome valences on agency rating. (b) Scatterplots of the positive correlation between anxiety and agency in the high-load effort with miss outcome condition. The blue dotted line represents the 95% confidence interval. (c) Scatterplots of the positive correlation between self-efficacy and agency in the medium-load effort with win outcome condition. The blue dotted line represents the 95% confidence interval. (d) The Pearson correlation analysis matrix of the participants' characteristics and agency ratings during the pre-iTBS test. HE = high-load effort, ME = medium-load effort, LE = low-load effort. ⁣^∗P < 0.05; ⁣^∗∗P < 0.01; ⁣^∗∗∗P < 0.001.

Figure 4

fNIRS results of effort and outcome processing during the judgment of agency task. (a) The observed activated channels in the high-load effort condition. ch1 (x = 73, y = −23, z = 8) corresponds to BA22-superior temporal gyrus (STG); ch6 (x = 64, y = −13, z = 24) corresponds to BA6-pre-motor and supplementary motor area (pre-SMA); ch7 (x = 55, y = −20, z = −9) and ch37 (x = −54, y = −17, z = −9) correspond to BA38-temporopolar area (TP); ch34 (x = −54, y = 40, z = −9) corresponds to BA47-inferior frontal gyrus (IFG). (b) Main effect of effort load on β-value (block based). (c) The observed activated channels in the medium-load effort with positive outcome conditions. ch19 (x = 12, y = 44, z = 45), ch20 (x = 0, y = 53, z = 43), ch21 (x = −11, y = 44, z = 54) and ch26 (x = −22, y = 51, z = 43) correspond to BA9-DLPFC. (d) The main effect of effort load on β-value in the win and miss outcome condition (trial based). ⁣^∗P < 0.05; ⁣^∗∗P < 0.01.

Figure 5

Network plot based on partial correlation estimator. Network plot of the activated channels and agency ratings in the high-load effort condition. Only significant correlation edges (P < 0.05) are displayed.

Figure 6

Behavioral and fNIRS results of iTBS over the left DLPFC on the judgment of agency rating in the win outcome condition. (a) The main effect of pre- and post-test on agency. (b) The main effect of effort loads on agency. (c) The activated channels were observed by comparing the posttest and pretest in the iTBS and sham groups. ch22 (x = 16, y = 72, z = 18) corresponds to BA11-orbitofrontal cortex (OFC); ch27 (x = −27, y = 67, z = 14) corresponds to BA10-frontopolar cortex (FPC); ch28 (x = −39, y = 53, z = 27) corresponds to left BA46-DLPFC; ch30 (x = −46, y = 35, z = 35) corresponds to BA45-pars triangularis Broca's area (PTB). ⁣^∗P < 0.05, ⁣^∗∗∗P < 0.001.