Task-dependent Effects of TMS on the Neural Biomarkers of Episodic Memory
- Conditions
- Normal Physiology
- Interventions
- Device: TMS
- Registration Number
- NCT04694131
- Brief Summary
Background:
Transcranial magnetic stimulation (TMS) of the brain has been used to change the activity and
connections in the brain to improve memory. Researchers are interested in how these brain changes cause memory improvements and how activity at the time of stimulation may change the effects of TMS.
Objective:
To learn how brain stimulation can be used to improve memory.
Eligibility:
Healthy adults ages 18-40
Design:
Participants will be screened with a medical record review.
Participants will have 3 study visits.
At visit 1, participants will have a physical exam and will talk about their health. They will have magnetic resonance imaging (MRI). The MRI scanner is a metal cylinder surrounded by a strong magnetic field. During the MRI, participants will lie on a table that can slide in and out of the scanner. A coil will be placed over the head. Participants will be asked to keep their eyes focused on a small cross on a computer screen inside the scanner. The scanner makes loud noises. Participants will get earplugs.
At visits 2 and 3, participants will have TMS and perform tasks. For TMS, a wire coil encased in plastic is held on the scalp. When the coil is triggered, a brief electrical current passes through the coil and creates a magnetic pulse that stimulates the brain. During TMS, an electroencephalogram (EEG) will record brain activity. For the EEG, a cloth cap with electrodes is fitted on the participant s head. Participants will complete a memory task and a spatial processing task. They will also complete surveys about their mental state.
Participation will last 2-3 weeks.
...
- Detailed Description
Study Description:
The Behavioral Neurology Unit studies the human brain systems underlying learning and adaptation with the goal of finding interventions to make these processes more efficient. In this study, we are interested in examining how the task state of the episodic memory network influences the effect of faciliatory TMS on memory and its EEG neural correlates. It is hypothesized that Network-targeted parietal-TMS will improve memory performance and enhance EEG biomarkers of successful memory performance, but that these changes will be modulated by the ongoing task activity
during stimulation.
Objectives:
Primary Objectives:
* Investigate how TMS modulates EEG neural measures of successful memory and the association of this modulation with behavioral performance
* Examine how memory task state influences susceptibility to plasticity via TMS and determine the optimal neural state for improving memory
Exploratory Objectives:
-Search for MRI predictors of the effects of TMS
Endpoints:
* Primary Endpoints: Memory performance, Late Positive Posterior ERP, evoked theta/alpha power (secondary), EEG functional connectivity (secondary)
* Exploratory Endpoints: fMRI resting state functional connectivity, fractional anisotropy
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 33
Not provided
Not provided
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- SINGLE_GROUP
- Arm && Interventions
Group Intervention Description MS TMS All participants will receive all conditions and the order of all conditions will be counterbalanced across participants. Statistical comparisons will be within-subjects. There will be two experiment days, during which TMS will be delivered during the behavioral tasks (spatial task trials and encoding phase of the memory task). Participants will receive TMS delivered to parietal cortex on one day and vertex stimulation on the other day. Each experiment day will include one block of TMS delivered prior to task trial onsets and one block delivered simultaneously with trial onsets.
- Primary Outcome Measures
Name Time Method Late Positive Posterior ERP Immediate ERP amplitude 500-700 ms after trial onset (encoding and retrieval) over parietal and occipital electrodes
Memory performance 1 hour Accuracy: Percentage of successful (later remembered hit and correct rejection) vs unsuccessful (forgotten miss and false alarm) trials for item recognition (remember /familiar/new) and context recollection (spatial location): Analysis of hits (correctly remembered as encoded) relative to false alarms (new objects labelled as encoded) for item recognition
- Secondary Outcome Measures
Name Time Method Theta/Alpha power Immediate Power in the 4-13 Hz band 0-1000 ms after trial onset (encoding and retrieval)
DTI structural connectivity 1-7 days before intervention Fractional anisotropy (FA) at baseline between the hippocampus and cortical regions
fMRI functional connectivity 1-7 days before intervention Resting state functional connectivity at baseline between the hippocampus and cortical regions
EEG functional connectivity Immediate Pearson correlation coefficients (r) between electrode time courses after trial onset (encoding and retrieval)
Trial Locations
- Locations (1)
National Institutes of Health Clinical Center
🇺🇸Bethesda, Maryland, United States