PDK4 and Cognitive impairment: While a similar profile was observed in hAPPWT mice at early and advanced ages, a 2- to 5-fold decrease in Ppara, Acox1, Cpt1a, and Pdk4 mRNA levels was observed (0.46 ± 0.04, 0.58 ± 0.06, 0.50 ± 0.10, 0.91 ± 0.06, respectively) in 11- to 12-month-old hAPPWT mice compared with WT littermates at the same age (Figure 2, C–F), an age at which severe cognitive deficits are detected (32, 35).