Discussion
This study evaluated the effects of lithium on ER in healthy participants. Neural effects of reappraisal, compared to naturally experiencing the negative stimuli, were seen, as expected, in frontal, temporal, parietal, and occipital regions, alongside lower self-reported negative affect ratings. Lithium’s effect on active reappraisal and emotional processing of negative images was seen in areas of the fronto-parietal and limbic network, and in superior and medial temporal structures. Within the fronto-parietal network, during reappraisal compared to maintain, lithium decreased activation in prefrontal areas (left anterior PFC or rostra-lateral PFC, and right superior frontal gyrus) and posterior parietal areas (left AG). In addition, exploratory PPI analyses revealed connectivity changes within prefrontal and limbic areas following lithium administration. These results show that lithium can affect the neural underpinnings of emotional regulation, though not in line with our a priori hypothesis, which may be useful for future neuropsychological models of mood stabilising action.