Discussion
affective disorders, overdose, cognitive impairment, depressive symptoms, mania/hypomania, depression, MDD, depressive disorders
DISEASE PROGRESSION, CORTEX
It was found that rTMS targeting of the visual cortex functionally connected to the ACC led to a significant improvement in the accuracy of Symbol Check in the THINC-it tests, reflecting working memory, executive function, and attention. However, targeting of the VC functionally anti-correlated with the DLPFC did not have a significant effect, nor were any significant within-group changes in the FC between DLPFC/ACC and the whole brain observed between the baseline and after active treatment in any group. One participant in the ACC active-sham group experienced an SAE, specifically, disease progression and an overdose of medication after ten active and two sham rTMS sessions. Otherwise, active rTMS targeting of V1 was well-tolerated by the rest of the subjects with reports of SAEs. A series of case reports have shown a link between rTMS and the development of treatment-induced mania/hypomania [Previous data have demonstrated that some medications may provide potential benefits to cognitive impairment in euthymic BD patients (e.g., cholinesterase inhibitors [Several researchers have recently focused on the visual cortex and studied its potential role in the development of the depression phenotype in depressive disorders. A recent study using fMRI-based neuro-navigated rTMS administered to 74 patients with depression showed that five days of active rTMS positioned over the VC was superior to sham stimulation in mitigating depressive symptoms, supporting the use of the VC as a stimulation target for effective rTMS treatment in MDD [Notably, there is also mounting evidence of the importance of the early VC (V1–V3) in working memory, through the maintenance of information associated with specific cognitive functions such as spatial orientation [Additionally, neuroimaging studies have emphasized the association of ACC with affective disorders [Furthermore, research on rodents has demonstrated that the ACC receives anatomical input from the VC [Although the FC between DLPFC/ACC and the whole brain did not show significant within-group changes, the results indicated the presence of stronger FC between the ACC and the left hippocampus after active rTMS treatment if the images were not corrected by multiple comparisons. Previous evidence indicated that active rTMS could induce significant changes not only in regions close to the stimulation site but also in more distal regions that are anatomically or functionally interconnected with the stimulation site [There were some limitations to the present study. First, the experimental design using the time to acquire the second fMRI data after active treatment did not allow a comparison of the difference between the effects on FC between active and sham rTMS. Second, the stimulating coordinate in the V1 was calculated based on the group level, instead of individually targeting regions functionally relevant to the DLPFC or ACC, and the coordinates of the DLPFC and ACC were selected according to two previous studies instead of our own dataset of the subjects enrolled in the study. Third, there were deficiencies in data in terms of follow-up with no rTMS sessions; further studies are required to verify long-term effects after the completion of the rTMS treatment. Fourth, the sample size was fairly small, and the numbers of participants in four groups were unsymmetrical. Fifth, there was a lack of control groups. Sixth, medications that may have influenced the cognitive function of the participants in each group were not the same. Finally, the cognitive test inevitably confronts the challenge of practice effects, and longer follow-up times are needed to avoid this problem in future research.