GDF11 and memory impairment: In the Y-maze test (used to assess recognition memory), young and GDF11-treated aged mice spent significantly more time investigating the novel arm of the maze than aged mice (aged, 24.4 ± 2.7%; young, 36.1 ± 2.9%; GDF11 = 36.9 ± 3.7%), confirming the effect of GDF11 in improving age-related memory impairments (Fig. 1d).