Figure 9.

Male ERK2 CKO mice have deficits in associative learning. Male ERK2 CKO mice displayed deficits in cued and contextual fear conditioning. A, At 24 h after training, CKOs showed significantly less freezing behavior when tested for contextual and cued recall (t₍₁₆₎ = 2.27 and 2.95, respectively; p < 0.05). B, Repeated training, or “overtraining,” did not overcome the deficit seen in cued and contextual fear conditioning. CKOs showed significantly less freezing behavior in both recall tests when tested the next day (t₍₁₆₎ = 3.65 and 3.35, respectively; p < 0.05). *p < 0.05.