Medial frontal cortex (MFC) D1DR blockade impairs timing without changing other aspects of behavior. A, The timing of responses (i.e., when animals pressed the lever) during interval timing for control sessions (blue) versus MFC D1DR blockade sessions (red) in nine animals. B, Average response time was shorter in sessions with MFC D1DR blockade (red) compared with control (blue). *p < 0.05. C, Curvature indices of time–response histograms were less in MFC D1DR sessions (blue) compared with control sessions. *p < 0.05. D–F, MFC D1DR blockade did not change the duration of lever press (i.e., time the lever was held down; D), the number of overall lever presses (E), or the number of overall rewards (F). Additionally, MFC D1DR blockade did not consistently change open-field behavior or othergross motor parameters. All plots are of mean ± SEM.