Neuromodulation and Attention Deficits in MDD

University of Electronic Science and Technology of China60 enrolled

Overview

Multimodal study (Behavior, TMS, EEG) combining a sham-controlled intermittent theta burst stimulation (iTBS) intervention with an additional-singleton task and EEG to evaluate whether left dorsolateral prefrontal cortex (DLPFC) stimulation enhances cognitive control and modulates maladaptive attention processes in MDD and whether the effects are influenced by neuronavigated versus manual (Beam F3 method) localization of the stimulation site.

Major Depressive Disorder (MDD) is associated with impaired selective attention and disrupted top-down control, yet the underlying neurophysiological mechanisms remain poorly understood. The present double-blind, sham-controlled trial will test whether iTBS over the left DLPFC, an FDA-approved rTMS site, can restore top-down distractor suppression in MDD (active-iTBS: n = 30; sham-iTBS: n = 30). Neuronavigated iTBS will be delivered across sessions, and effects will be assessed on the behavioral level (additional singleton paradigm) and the neurophysiological level (using concomitant EEG). Key aim of the project is to compare neuronavigated (active-iTBS) versus manual (Beam F3 method, sham-iTBS group) localization of the stimulation site.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Enrollment

Conditions

Major Depression Disorder Cognitive Deficits

Interventions

intermittent theta burst stimulation (iTBS) interventionDEVICE

iTBS protocol: Intervention with an 80-120% resting threshold was used. In the active group, the left dlPFC was selected as the stimulation site and a stimulation protocol with iTBS parameters was given. This was a neuro-modulation protocol of excitatory sequences, with theta burst stimulation at 50 Hz, repeated at 5 Hz, stimulation for 2 s with an interval of 8 s, for a total of 1,800 pulses, with a treatment time of about 20 min/session, two sessions per day, with a15-30 min rest between sessions, and five consecutive days of treatment per week, with a rest of 2 days, and two weeks of treatment.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 55 Years

Medical Language ↔ Plain English

Inclusion Criteria: * 18-55 years * Right-handed * Normal or corrected normal visual acuity * MDD: meet the proposed DSM-5 MDD criteria, unmedicated or stable medicated within the last one month. Healthy subjects without any past or present psychiatric or neurological disorders. Exclusion Criteria: * Diagnosis of other severe mental disorders, such as schizophrenia, bipolar disorder, neurodevelopmental disorder, etc. * high suicidal risk * Unnormal intellectual functioning, auditory impairments, * Have received neuromodulation, such as Modified Electroconvulsive Therapy (MECT), or any psychotherapy within the past 6 months. * Only for the active-iTBS group: have a contraindication to MRI scanning (e.g., metal implants, claustrophobia or other conditions that make them inappropriate for MRI scanning).

Outcomes

Primary Outcomes

Depression severity following two weeks of iTBS treatment.

Depression severity will be assessed, using 24-item Hamilton Depression Scale (HAMD-24) before and after the iTBS intervention. Changes will be computed as (pre-treatment score - post-treatment score)/pre-treatment score × 100%). We hypothesize that the neuronaviogated group has a better treatment effect indexed by the mean HAMD subtraction rate than the sham-control group.

Time frame: 60-90 minutes before the first iTBS treatment and 60-90 minutes after last iTBS treatment.

Secondary Outcomes

Intervention-related ERPs changes in the additional singleton task after 2 weeks of active/sham iTBS treatment.

Neuromodulation-induced iTBS changes will be measured by the probability cueing effects in the additional singleton task with ERP effects. N2pc and Pd components will be used to quantify attentional selection and distractor suppression. These ERP components reflect the neural mechanisms of spatial attention in MDD.

Time frame: 30-60 minutes before the first iTBS treatment and 30-60 minutes after last iTBS treatment.

Intervention-related brain connectivity after 2 weeks of active/sham iTBS treatment.

During the additional singleton task, we will measure network-level connectivity patterns between attention-related brain regions (e.g., fronto-parietal and sensory integration systems). Directed or undirected EEG connectivity methods (e.g., phase synchronization, Granger causality, or sPDC) will be applied to assess iTBS-induced changes in intrinsic attentional network architecture in MDD.

Time frame: 30-60 minutes before the first iTBS treatment and 30-60 minutes after last iTBS treatment.

Intervention-related behavior changes in the additional singleton task after 2 weeks of active/sham iTBS treatment.

Neuromodulation-induced iTBS changes will also be measured in RTs. We aim to examine whether the different RT effects in both groups occur between the pre-iTBS and post-iTBS conditions. For the between-group effect, compared to the sham-iTBS group, the active-iTBS group has faster RTs and statistical learning effects (e.g., subtraction RTs from the low-minus-high-probability distractor locations).

Time frame: 30-60 minutes before the first iTBS treatment and 30-60 minutes after the last iTBS treatment.