PSEN1 and Alzheimer disease: Notably, no significant behavioral differences were found between the APP/PS1 and APP/PS1 + HFD groups (Figures 2A–E) in this study, suggesting that feeding a diet at a level of 45% calorie from fat for as long as 6 months does not lead to a detriment of exploration ability, spatial learning and memory in the female transgenic mouse model of AD.