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| Name | Class |
|---|---|
| University Ghent | OTHER |
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This experimental study investigated how MRI-compatible transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex (DLPFC) modulates neural and cognitive responses to social criticism in healthy volunteers.
Participants underwent two MRI sessions - one with active and one with sham stimulation - in a randomized, double-blind, cross-over design.
During stimulation, they completed resting-state and task-based fMRI scans including exposure to critical, neutral, and praising auditory comments, followed by behavioral and self-report measures of rumination, mood, and implicit self-esteem.
This study aimed to examine the effects of non-invasive brain stimulation on emotional and self-referential processing. Healthy right-handed female participants completed two identical MRI sessions separated by at least 48 hours and a maximum of 2 weeks. The localization of the left dorsolateral prefrontal cortex (DLPFC) was determined during the first session. Anatomical data were first acquired using a high-resolution T1-weighted structural scan. Participants were then briefly removed from the MRI scanner to define the stimulation target using two complementary methods: (1) the standard scalp position F3 according to the 10-20 international EEG system, and (2) an individualized neuronavigation procedure targeting the mid-center of the left middle frontal gyrus (Brodmann areas 9/46) based on each participant's structural MRI. For the actual tDCS sessions, only the neuronavigation-derived DLPFC target was used for electrode placement.
In each session, participants received either active or sham MRI-compatible tDCS (1.5 mA, 20 minutes) applied over the left DLPFC with the cathode placed over the contralateral supra-orbital region. The order of stimulation (active vs. sham) was randomized and counterbalanced. The location of the DLPFC electrode placement was based During fMRI, participants completed multiple scans: a T1 structural scan, resting-state sequences (pre-, during-, and post-stimulation), resting-state sequences (pre-, during-, and post-auditory criticism task with blocks of critical, neutral, and praising comments), and an arterial spin labeling (ASL) perfusion sequence.
Self-report measures of state rumination (Momentary Ruminative Self-focus Inventory, MRSI) and mood (visual analogue scales) were collected before and after stimulation and after the criticism paradigm. An implicit self-esteem task (Implicit Relational Assessment Procedure, IRAP) followed the MRI session. Trait questionnaires and a blood sample for DNA (e.g. 5-HTTLPR) analysis were collected at baseline only.
The primary goal was to assess whether active tDCS modulates neural and behavioral markers of self-referential processing and emotional regulation compared with sham stimulation.
No serious adverse events occurred during the study. Minor sensations (tingling, mild scalp discomfort) were transient and self-limited.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Active tDCS | Active Comparator | Participants receive MRI-compatible transcranial direct current stimulation (tDCS) using a NeuroConn DC-Stimulator MR. A constant current of 1.5 mA is applied for 20 minutes with the anodal electrode positioned over the left dorsolateral prefrontal cortex (DLPFC) using neuronavigation and the cathodal electrode positioned over the contralateral supra-orbital area. Stimulation is delivered while participants are in the MRI scanner. |
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| Sham tDCS | Placebo Comparator | Participants receive sham MRI-compatible transcranial direct current stimulation using a NeuroConn DC-Stimulator MR. The electrodes are positioned identically to the active condition. The current is ramped up and down during the first 30 seconds to mimic the initial sensation of stimulation, after which no current is delivered for the remainder of the 20-minute session. Stimulation is administered while participants are in the MRI scanner. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| tDCS | Device | Participants are randomized to receive either active or sham tDCS during MRI scanning. Neuroimaging and behavioral outcomes are used to assess the effects of stimulation on emotion-related brain networks. |
| Measure | Description | Time Frame |
|---|---|---|
| Change in perfusion | Cerebral blood flow measured using arterial spin labeling (ASL) functional MRI before and after tDCS and after the criticism paradigm. Unit of Measure: mL/100 g/min | Baseline; during tDCS; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) |
| Neural reactivity to praise and criticism | Blood-oxygen-level dependent (BOLD) signal change during blocks of praising, neutral, and critical comments measured using task-based fMRI. Unit of Measure: Percent signal change (or beta values from the general linear model) | Periprocedural |
| Resting-state functional connectivity within emotion-regulation networks | Functional connectivity strength between prefrontal and limbic regions measured using resting-state fMRI before, during, and after tDCS. Unit of Measure: Fisher-z transformed correlation coefficients | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) |
| Measure | Description | Time Frame |
|---|---|---|
| Change in momentary rumination | Momentary rumination assessed using the Perseverative Thinking Questionnaire (PTQ). Unit of Measure: PTQ total score. A higher score means more rumination. | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) |
| Implicit self-esteem (Implicit Relational Assessment Procedure, IRAP) |
| Measure | Description | Time Frame |
|---|---|---|
| Serotonin transporter genotype | Serotonin transporter promoter polymorphism (5-HTTLPR) determined from baseline DNA samples. Unit of Measure: Genotype category (e.g., LL, LS, SS) | Baseline (prior to any intervention) |
| Temperament and Character Inventory (TCI) |
Inclusion Criteria:
Exclusion Criteria:
Female
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| UZ Gent | Ghent | Oost-Vlaanderen | 9000 | Belgium |
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| ID | Term |
|---|---|
| D065908 | Transcranial Direct Current Stimulation |
| ID | Term |
|---|---|
| D004599 | Electric Stimulation Therapy |
| D013812 | Therapeutics |
| D003295 | Convulsive Therapy |
| D013000 | Psychiatric Somatic Therapies |
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Implicit self-esteem assessed using the Implicit Relational Assessment Procedure (IRAP). Unit of Measure: D-IRAP score (reaction-time-based index): D-IRAP score (typically ranging approximately from -2 to +2) |
| Baseline and post tDCS |
| Spatial deviation between targeting methods | Euclidean distance between the dorsolateral prefrontal cortex (DLPFC) target coordinates derived from EEG 10-20 F3 positioning and MRI-based neuronavigation. Unit of Measure: Millimeters (mm) | Baseline (prior to any intervention) |
| Mood ratings-tension | Self-reported tension measured using a visual analogue scale (VAS) Unit of Measure: Score on a 0-10 scale. A higher score means more tensed. | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) |
| Momentary mood ratings - fatigue | Self-reported fatigue measured using a visual analogue scale (VAS). Unit of Measure:Score on a 0-10 scale. A higher score means more fatigued. | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) |
| Momentary mood ratings - vigor | Self-reported vigor measured using a visual analogue scale (VAS). Unit of Measure: Score on a 0-10 scale. A higher score means more vigor. | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) |
| Momentary mood ratings - anger | Self-reported anger measured using a visual analogue scale (VAS). Unit of Measure: Score on a 0-10 scale. A higher score means more anger. | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) |
| Momentary mood ratings - depressed mood | Self-reported depressed mood measured using a visual analogue scale (VAS). Unit of Measure: Score on a 0-10 scale. A higher score means more depressed mood. | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) |
| Momentary mood ratings - cheerfulness | Self-reported cheerfulness measured using a visual analogue scale (VAS). Unit of Measure: Score on a 0-10 scale. A higher score means more cheerfulness. | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) |
Temperament and character traits assessed using the Temperament and Character Inventory (TCI). Unit of Measure: TCI-240 true/false items. Temperament traits assessed using the TCI (NS, HA, RD, P subscales) and Character traits assessed using the TCI (SD, C, ST subscales). TCI subscale scores (NS 0-40; HA 0-35; RD 0-24; P 0-8; SD 0-44; C 0-42; ST 0-33) Higher scores indicate greater expression of that trait. |
| Baseline (prior to any intervention) |
| Perceived criticism sensitivity | Perceived criticism assessed using the Perceived Criticism Measure (PCM), a single-item rating of how critical a significant other is perceived to be. Unit of Measure: PCM score (range 1-10; higher scores indicate greater perceived criticism) | Baseline (prior to any intervention) |
| Trait anxiety | Trait anxiety assessed using the State-Trait Anxiety Inventory - Trait version (STAI-T). Unit of Measure: STAI-T total score (range 20-80; higher scores indicate greater trait anxiety). | Baseline (prior to any intervention) |
| Explicit self-esteem | Explicit self-esteem assessed using the Rosenberg Self-Esteem Scale (RSES). Unit of Measure: RSES total score (range 10-40; higher scores indicate higher self-esteem). | Baseline (prior to any intervention) |
| Psychological inflexibility | Psychological inflexibility assessed using the Acceptance and Action Questionnaire-II (AAQ-II). Unit of Measure: AAQ-II total score (range 7-49; higher scores indicate greater psychological inflexibility) | Baseline (prior to any intervention) |
| Cognitive emotion regulation strategies | Cognitive emotion regulation strategies assessed using the Cognitive Emotion Regulation Questionnaire (CERQ). Unit of Measure:Cognitive emotion regulation strategies assessed using the CERQ, reported as subscale scores. CERQ subscale scores each ranging 4-20. A higher score means less Cognitive emotion regulation strategies. | Baseline (prior to any intervention) |
| Trait rumination | Trait rumination assessed using the Ruminative Responses Scale (RRS). Unit of Measure: RRS total score (range 22-88; higher scores indicate greater trait rumination). | Baseline (prior to any intervention) |
| D004191 | Behavioral Disciplines and Activities |
| D004597 | Electroshock |
| D011580 | Psychological Techniques |