Figure 3.

Disruptive phase shift (DPS) in entrained Siberian hamsters induced by exposure to an extra 5 hours of light on one day produces permanent arrhythmia and eliminates the capacity for memory formation as measured by the novel object recognition test (long-term memory) and the spontaneous alternation test (working memory). Arrhythmia induced by SCN lesions does not disrupt these forms of recognition memory. In animals made arrhythmic by the DPS, complete SCN lesion restores their capacity to form object memories. Open circles represent sham-operated animals, gray circles represent animals with partial SCN lesions, and black circles represent the behavior of animals with complete SCN lesions. The first data set in part C is entrained animals, the second data set comes from arrhythmic DPS animals, and the third data set is animals that received complete SCN lesions (black), partial SCN lesions (gray), or sham lesion operations (white; from Fernandez et al. 2014, Science).