Ketamine affected the directional connectivity between the lPFC and PPC in the time domain (Granger prediction). A, In Monkey A, Granger prediction is overall stronger in the lPFC-lead than the PPC-lead model (left vs right set of bars). Ketamine significantly reduced their connectivity in both RV and RM tasks and under both prosaccade (light vs dark red) and antisaccade (light vs dark blue) rules. B, In Monkey C, ketamine induced the same set of changes in Granger prediction. *p < 0.05, **p < 0.005, ***p < 0.0005.