Left Dorsolateral Prefrontal Cortex - Accelerated Intermittent Theta Burst, Left Primary Somatosensory Cortex - Accelerated Intermittent Theta Burst, Left Rostromedial Prefrontal Cortex - Accelerated Intermittent Theta Burst
Conditions
Keywords
Transcranial Magnetic Stimulation, Major Depressive Disorder, Positive Affect, Anhedonia, Savoring
Brief summary
This is a non-invasive brain stimulation and neuroimaging study that will examine how activity in the medial prefrontal cortex influences reward processing, particularly positive savoring, in individuals with depression. The central question is whether modulating medial prefrontal brain regions using transcranial magnetic stimulation (TMS) alters neural and behavioral responses to rewards. Brain activity will be recorded using both electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) while participants perform reward tasks. The primary objectives are to (1) identify patterns of brain activity linked to impaired reward processing in depression using EEG and fMRI, and (2) determine the causal role of specific prefrontal areas in these processes through targeted TMS. The methods include four sessions over four weeks: a clinical assessment, EEG recording during reward tasks after participants learn/practice positive savoring, an fMRI session, and a TMS session combined with EEG while participants practice positive savoring and perform reward tasks during EEG.
Interventions
DEVICEAccelerated Intermittent Theta Burst Transcranial Magnetic Stimulation
For accelerated intermittent theta burst stimulation (aiTBS), stimulation intensity will be set at 80% resting motor threshold (rMT), a level that has been established to be safe and effective. aiTBS will consist of bursts containing 3 pulses at 50 Hz. Bursts will be delivered at 5 Hz for 2 seconds at 80% of rMT, followed by 8 seconds without stimulation. This pattern will continue for 60 cycles (1800 pulses), for a total elapsed time of 10 minutes. Participants will be randomized to receive aiTBS to their mPFC, dlPFC, or primary somatosensory cortex (S1) a total of two times in a single session for 10 minutes each (spaced 50 minutes apart) before/after EEG preparation and practicing a positive affect technique (i.e., savoring), and before performing a positive savoring and reward responsivity task during EEG.
Sponsors
Florida State University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Intervention model description
Parallel randomized and active controlled study. Participants will be randomized to receive accelerated intermittent theta burst stimulation to one of three target brain regions (left rostromedial PFC, left dorsolateral PFC, or left primary somatosensory cortex).
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Between the ages of 18 and 65 * Able to provide informed consent * Have normal or corrected vision * Right handed * Willing to comply with all study procedures and be available for the duration of the study * Speak and understand English * Not color blind * Acceptable suicide risk as determined by less than 5 on the Depression Symptom Index Suicidality Subscale (DSI-SS) * A diagnosis of major depressive disorder (current episode) on the Structured Clinical Interview for the DSM-5 (SCID-5) * Between the ages of 18 and 65
Exclusion criteria
* ADHD (currently under treatment) * Neurological disorders and conditions. Including but not limited to: history of epilepsy, seizures (except childhood febrile seizures), dementia, history of stroke, Parkindon's disease, multiple sclerosis, cerebral aneurysm, brain tumors * Medical or neurological illness or treatment for a medical disorder that could interfere with study participation. For example, unstable cardiac disease, HIV/AIDS, malignancy, liver or renal impairment * Prior brain surgery * Any brain devices/implants, including cochlear implants and aneurysm clips, cardiac pacemaker, or any other implanted electronic device * History of current traumatic brain injury * Pregnancy (for females) * Claustrophobia * DSM-5 diagnosis of present moderate or severe substance use disorder or alcohol use disorder, and past severe substance use disorder or alcohol use disorder, bipolar disorder, or psychotic disorder * Based on the use of MRI, additional
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Late Positive Potential during Positive Savoring | From baseline EEG to post-stimulation EEG approximately 2 weeks apart | The late positive potential (LPP) is an established event-related potential that has been shown to be higher when savoring positive feelings elicited by positive images compared to neutral images. Changes in the LPP will be assessed from baseline EEG to post-stimulation EEG and compared between stimulation sites (left rostromedial PFC, left dorsolateral PFC, left primary somatosensory cortex). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Positive Affect Ratings on the Positive and Negative Affect Schedule (PANAS) | From the start to the end of a 3 hour study visit | Positive Affect subscale ratings on the Positive and Negative Affect Schedule (PANAS) self-report measure will be collected at the start and end of the stimulation visit, which will be used to assess the secondary outcome of acute positive affect change. The full PANAS measure includes 20 items with Negative Affect (NA) and Positive Affect (PA) subscales of 10 items each. Scores can range from 10-50, with higher scores representing higher levels of either NA or PA. This will be compared across the three stimulation sites. |
Countries
United States
Outcome results
None listed