D2 transmission and sequential working memory
sleepiness, behavioral deficits
A second novel finding is that D2 receptor activation can negatively affect sequential working memory. Pramipexole can impair sequence maintenance by inhibiting maintenance-related STN activity and impair sequence manipulation by enhancing manipulation-related STN activity. Another possibility is that pramipexole slowed down information processing in general, although sleepiness and other side effects of pramipexole have been minimized. Additionally, despite no direct correlation, pramipexole-induced dlPFC activity pattern similarity or fronto-subthalamic functional connectivity change might produce behavioral deficits.This finding is not entirely consistent with previous pharmacological studies and dopaminergic models of visuospatial working memory. For example, the D2 receptor agonist bromocriptine and the partial agonist aripiprazole can increase the dlPFC activity for maintaining visual objects or spatial locations [The inconsistency between our observation and previous studies is not unexpected. The cognitive and neural mechanisms that encode and retrieve sequential information may differ from those that encode and retrieve visuospatial information. For example, Ranganath and colleagues found that frontal theta power was enhanced for maintaining serial positions over visual features of the same item in healthy adults [