Healthy Participant Study
Conditions
Keywords
tDCS, Criticism, neuronavigation, DLPFC, fMRI, MRI, DNA, ASL
Brief summary
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.
Detailed description
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.
Interventions
DEVICEtDCS
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.
Sponsors
Universitair Ziekenhuis Brussel
University Ghent
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* Female participants aged 18-35 years. * Right-handed, healthy volunteers. * No current or past psychiatric or neurological disorder as assessed by structured clinical interview (M.I.N.I.). * MRI-compatible (no metal implants, pacemaker, or contraindications for MRI scanning). * Not taking psychotropic medication. * Fluent in Dutch. * Provided written informed consent.
Exclusion criteria
* Current or past major depressive episode or any other psychiatric disorder. * History of epilepsy or seizures in participant * History of neurological illness or neurosurgical intervention. * Pregnancy. * Claustrophobia or inability to tolerate MRI environment. * Metal implants or other MRI-incompatible devices. * Skin lesions or dermatological conditions at electrode sites. * Unstable medical condition. * Use of medication that could influence brain activity or mood.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in perfusion | Baseline; during tDCS; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) | 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 |
| Neural reactivity to praise and criticism | Periprocedural | 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) |
| Resting-state functional connectivity within emotion-regulation networks | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) | 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 |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in momentary rumination | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) | Momentary rumination assessed using the Perseverative Thinking Questionnaire (PTQ). Unit of Measure: PTQ total score. A higher score means more rumination. |
| Implicit self-esteem (Implicit Relational Assessment Procedure, IRAP) | Baseline and post tDCS | 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) |
| Spatial deviation between targeting methods | Baseline (prior to any intervention) | 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) |
| Mood ratings-tension | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) | 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. |
| Momentary mood ratings - fatigue | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) | 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. |
| Momentary mood ratings - vigor | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) | 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. |
| Momentary mood ratings - anger | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) | 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. |
| Momentary mood ratings - depressed mood | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) | 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. |
| Momentary mood ratings - cheerfulness | Baseline; immediately post-tDCS; and immediately post-criticism paradigm (single study visit) | 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. |
Countries
Belgium
Outcome results
None listed