Transcranial Magnetic Stimulation
Conditions
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 (T-A-B-L-E-T) and spatial sequence (Top-Bottom Right-Left-Right-Bottom Left-Top) 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 previously described in published work. The focus in this study will be comparison of MFG-TMS, IPL-TMS, and S1-TMS in an interleaved fMRI-TMS-fMRI design. The logic is to test the apical status of the MFG/IPL through the extent to which TMS impacts other PFC/PPC areas and behavior. Each experiment will begin with 1 session of the CCT with fMRI to localize TMS 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.
Interventions
DEVICEtranscranial magnetic stimulation
Transcranial magnetic stimulation delivered to the scalp targeting specific brain structures via stereotactic guidance.
Sponsors
Florida State University
National Institute of Mental Health (NIMH)
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
* Between the ages of 18 and 30 * Right-handed * Native English speaker or fluent by the age of 6
Exclusion criteria
* 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 * Tinnitus * Women who are pregnant
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in 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) \[note, this measure has no units\] |
| Change in 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
| Measure | Time frame | Description |
|---|---|---|
| Change in contextual control speed | baseline, pre-intervention and immediately after intervention | behavioral performance (reaction time in milliseconds) on conditions involving contextual control in the comprehensive control task |
| Change in contextual control accuracy | baseline, pre-intervention and immediately after intervention | behavioral performance (reaction time in milliseconds) on conditions involving contextual control in the comprehensive control task |
| Change in temporal control speed | baseline, pre-intervention and immediately after intervention | behavioral performance (reaction time in milliseconds) on conditions involving temporal control in the comprehensive control task |
| Change in temporal control accuracy | baseline, pre-intervention and immediately after intervention | behavioral performance (percent correct) on conditions involving temporal control in the comprehensive control task |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORDerek Nee, PhD
Florida State University
Outcome results
None listed