cTBS/fMRI Study of Hierarchical Control in the PFC
- Conditions
- Transcranial Magnetic Stimulation
- Interventions
- Device: transcranial magnetic stimulation
- Registration Number
- NCT04464473
- Lead Sponsor
- Florida State University
- Brief Summary
The objective of this study is to examine the effect of transcranial magnetic stimulation (TMS) on the prefrontal cortex and posterior parietal cortex.
- Detailed Description
The Comprehensive Control Task (CCT) was designed to examine hierarchical control in a single, well-controlled factorial task. On each trial, participants view a letter surrounded by a colored shape at a particular screen location. Color cues the relevant feature, letter or location, for a block of trials. The first trial of a block requires a decision of whether the stimulus is the first position of a circular sequence (sequence start). Subsequent trials require a decision of whether the viewed stimulus follows the previous stimulus in a circular sequence (sequence 1-back). The letter sequence (C-O-M-I-C) and spatial sequence (Top Left-Top Right-Bottom Left-Bottom Right-Top Left) are difficulty-matched.
Shape cues the task to perform. Squares indicate the standard baseline task, and each block begins and ends with baseline trials. Different shapes indicate sub-tasks. In Switching blocks, shape-switches (e.g. from square to circle or circle to square) cue the sequence start task. Shape-repeats cue the sequence 1-back task. In Planning blocks, triangle shapes indicate that the stimulus can be ignored (automatic "no" response). All the while, the last square-shaped stimulus must be retained as a reference for the next square-shaped stimulus. Finally, in Dual blocks, diamond shapes indicate switching (sequence start) and also planning. The reversion back to square shapes requires sequence matching to the distal, previous square.
The design is factorial with stimulus-domain x contextual control x temporal control orthogonally manipulated. Full details of the CCT have been previous described in Nee \& D'Esposito, 2016; 2017.
The focus in this study will be comparison of FPl-TMS, MFG-TMS, and S1-TMS in an interleaved fMRI-TMS-fMRI design. The logic is to test the apical status of the FPl/MFG through the extent to which TMS impacts other PFC areas and behavior.
Each experiment will begin with 1 session of the CCT with fMRI to localize PFC targets. Each participant will then perform 3 counter-balanced sessions wherein a different site will be targeted by TMS followed immediately by fMRI on the CCT.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 50
- Between the ages of 18 and 30
- Right-handed
- Native English speaker or fluent by the age of 6
- History of psychiatric disorders
- History of neurological disorders
- Receiving medications for psychiatric or neurological disorders
- Familial history of epilepsy
- Taking any drugs or medications that are pro-epileptic
- Metal anywhere in the head excluding the mouth
- Tinnitus
- Women who are pregnant
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description MFG-TMS transcranial magnetic stimulation Transcranial magnetic stimulation to the middle frontal gyrus. 600 pulses delivered in 50 Hz bursts every 5 Hz for 40 seconds at 80% of active motor threshold.. S1-TMS transcranial magnetic stimulation Transcranial magnetic stimulation to primary somatosensory cortex. 600 pulses delivered in 50 Hz bursts every 5 Hz for 40 seconds at 80% of active motor threshold.. FPl-TMS transcranial magnetic stimulation Transcranial magnetic stimulation to the lateral frontal pole. 600 pulses delivered in 50 Hz bursts every 5 Hz for 40 seconds at 80% of active motor threshold.
- Primary Outcome Measures
Name Time Method PFC-PPC activation baseline, pre-intervention and immediately after intervention blood oxygenation level dependent (BOLD) signal in areas of the prefrontal and posterior parietal cortex assessed with functional magnetic resonance imaging (fMRI) \[note, this measure has no units\]
PFC-PPC effective connectivity baseline, pre-intervention and immediately after intervention effective connectivity among areas of the prefrontal and posterior parietal cortex in the blood oxygenation level dependent (BOLD) signal assessed with functional magnetic resonance imaging (fMRI) \[note, this measure has no units\]
- Secondary Outcome Measures
Name Time Method temporal control performance baseline, pre-intervention and immediately after intervention behavioral performance (reaction time in milliseconds, and percent correct) on conditions involving temporal control in the comprehensive control task
contextual control performance baseline, pre-intervention and immediately after intervention behavioral performance (reaction time in milliseconds, and percent correct) on conditions involving contextual control in the comprehensive control task
Trial Locations
- Locations (2)
Florida State University Psychology Department Building
🇺🇸Tallahassee, Florida, United States
FSU MRI Facility
🇺🇸Tallahassee, Florida, United States