Neural Mechanisms of Emotional Health in Traumatic Brain Injury Patients Undergoing rTMS Treatment

Research Objectives To investigate biomarkers related to emotional health among Veterans with TBI, identify brain impact of TBI on mood and cognition, and describe rTMS as potential non-invasive treatment for mood and cognition disorders. Design Pre-post intervention study design, in which the changes in effective connectivity of brain regions implicated in emotional processing are investigated before and after the application of high-frequency rTMS treatment in patients with TBI. Setting VA Palo Alto Health Care System. Participants The study involved a total of 32 participants who had suffered from mild traumatic brain injury (TBI) and were experiencing cognitive and emotional problems. Interventions The intervention used in the study is repetitive transcranial magnetic stimulation (rTMS). The rTMS treatment was administered using a high-frequency protocol, with a frequency of 10 Hz, over the left dorsolateral prefrontal cortex. Main Outcome Measures We investigated the effective connectivity of the cortico-limbic network comprised of 11 regions of interest which are part of the default mode, salience and executive control networks, known to be implicated in emotional processing. Results The results indicate that overall, among extrinsic connections, the strength of excitatory connections decreased while that of inhibitory connections increased indicating reduction in the activity of all the inspected brain regions after the neuromodulation. The cardinal region in the analysis was dorsal anterior cingulate cortex which is considered to be the most influenced during emotional health disorders. Conclusions Our findings implicate the altered connectivity of dorsal anterior cingulate cortex with left anterior insula and medial prefrontal cortex, after the application of rTMS, as a potential neural mechanism underlying improvement of emotional health. Our investigation highlights the importance of these brain regions as treatment targets in emotional processing in TBI. Author(s) Disclosures None.