Submission
| Title: | Targeting Negative-Self Referential Processing with Transcranial Magnetic Stimulation: Feasibility Studies |
| Presenter: | Susan Conroy |
| Institution: | Indiana University School of Medicine |
| Authors: | Susan K. Conroy1, Ho-Ching (Shawn) Wang1, Yu-Chien Wu1, Stephen Strakowski1, Paul Holtzheimer2 1: Indiana University School of Medicine 2: Geisel School of Medicine at Dartmouth and National Center for PTSD |
Abstract
| Background/Significance/Rationale: | Major Depressive Disorder (MDD) is common, debilitating, and often difficult to treat. Neuromodulation strategies such as Transcranial Magnetic Stimulation (TMS) can target specific neural circuits underlying particular symptoms, potentially 1) enhancing our understanding of neural mechanisms of illness and recovery, and 2) acting as novel therapeutics. We hypothesize that targeting the ventromedial prefrontal cortex (VMPFC) in the brain’s Default-Mode Network may normalize aberrant VMPFC activity seen in MDD, thereby improving excessive negative self-referential processing. Several methods needed to test such hypotheses, including an fMRI task and image guided TMS to VMPFC had not been used previously at IUSM. |
| Methods: | Four healthy volunteers completed structural and functional MRI (fMRI). fMRI included a Trait-Adjective Task, a negative self-referential processing task known to activate VMPFC. During the task, participants respond on a task pad whether they feel that each of a series of displayed adjectives (positive, negative, or neutral) applies to them. Three participants then participated in a simulated image-guided TMS session using their structural MRI data. Three-dimensional tracking of the participant’s head and the TMS coil were used to position the coil for peak stimulation of the targeted brain region. |
| Results/Findings: | Our team collected quality neural and behavioral data on the fMRI task; participants reported a tolerable experience. Simulated neuronavigated TMS showed feasibility and tolerability of positioning the device to stimulate VMPFC. |
| Conclusions/Discussion: | The fMRI task activated the VMPFC as predicted. The MRI and TMS protocols were replicable and tolerable. These procedures can now be used experimentally by our team with confidence. |
| Translational/Human Health Impact: | This project lays essential groundwork for my K12 project, “Targeting Negative-Self Referential Processing in Depression with TMS,” a longitudinal neuroimaging and behavioral study using these methods in the MDD population. We are hopeful that targeting aberrant VMPFC activity underlying excessive self-referential processing seen in MDD will result in symptom improvement. |
