Impact of dopamine to serotonin cell ratio in transplants on behavioral recovery and L-DOPA-induced dyskinesia

► Graft-derived improvements are correlated with dopamine but not serotonin cells. ► Grafted dopamine cells prevent negative effects of serotonin neurons on dyskinesia. ► Grafted serotonin neurons may aggravate L-DOPA-induced dysregulation of presynaptic activity.