Effects of Repetitive TMS on Cognition in Depression

According to the World Health Organization, MDD is attributed as the leading cause of disability worldwide, leaving 300 million individuals affected. Despite the efficacy of pharmacotherapy, a subset of MDD patients, classified as TRD, exhibit suboptimal response and thus require alternative treatment options such as rTMS. Emotional-laden "hot"and Neutral "cold" cognitions are shown to be dysfunctional in depression. Potential pro-cognitive effects remain inconclusive. In this study the investigators seek to investigate whether visual scanning patterns of emotionally laden images may be a biological marker and predictor of rTMS antidepressant efficacy. If so, then changes in visual scanning patterns are expected to precede clinical symptom improvement. Furthermore, changes in visual scanning patterns (which characterizes the state of hot cognition) are compared simultaneously to changes in cold cognition in order to elucidate the neural mechanisms underlying rTMS-induced changes in cognition. It is hypothesized that participants who are responders to rTMS will exhibit a decrease in the amount of time spent looking at dysphoric images will precede clinically detectable changes in mood as measured by a reduction in the scores on the 17-item Hamilton Depression Rating Scale (HDRS-17). The hypothesis for this study corresponds to the alleviation of the dysfunction within the hot cognitive system as a result of rTMS and a potential compensatory effect of cold cognition as a natural reaction of resetting the allocation of cognitive resources.