Investigations indicate that selective serotonin reuptake inhibitors (SSRIs) reorganize neural networks via a short window of neuroplasticity. Although previous findings support the effect of SSRIs on intrinsic functional connectivity, the influence of SSRI administration on connectivity during sequence motor learning remains unclear. Thus, the present study administered 20 mg escitalopram or placebo for 1-week to 60 healthy females experiencing simultaneous functional magnetic resonance imaging and sequence motor training. 

It assessed task-modulated functional connectivity with a psycho-physiological interaction (PPI) analysis in the thalamus, putamen, cerebellum, dorsal premotor, primary motor, supplementary motor, and dorsolateral prefrontal cortices. On comparing an implicit sequence learning condition to a control learning condition, it found a decrease in connectivity between the thalamus and bilateral motor regions after seven days of escitalopram intake. It also found a negative correlation between plasma escitalopram levels and PPI connectivity changes, with higher escitalopram levels associated with greater thalamo-cortico decrease. 

These findings indicate that escitalopram improves network-level processing efficiency during sequence motor learning, despite no behavioral changes. 

Sci Rep.2021;11. https://doi.org/10.1038/s41598-021-94009-7