Fig. 5.

Mean lever-press responses during tests of the sensitivity of the animals to the selective degradation of one instrumental action–outcome contingency in each of the lesioned groups. A, Sham. B, Shell.C, Core. For A–C, the left panel displays mean lever presses per minute across days of contingency degradation training, and the right paneldisplays the mean responses per minute on the two levers in an extinction test.