FYN and drug-induced dyskinesia: The role of D2-expressing indirect MSN (iMSN) in LID is still controversial and its specific chemogenetic stimulation reduces dyskinesia (Alcacer et al., 2017), it is then tempting to speculate that stimulation of iMSN may have an opposite functional role than on dMSN and therefore the effect of silencing Fyn in these two neuronal types could not be necessarily additive, contrariwise, they could be opposite.