High-Fat Diet Impairs Tactile Discrimination Memory in the Mouse.

Research on the impact of diet and memory has garnered considerable attention while exploring the link between obesity and cognitive impairment. High-fat diet (HFD) rodent models recapitulate the obesity phenotype and subsequent cognitive impairments. While it is known that HFD is associated with sensory impairment, little attention has been given to the potential role these sensory deficits may play in recognition memory testing, one of the most commonly used cognitive tests. Because mice utilize their facial whiskers as their primary sensory apparatus, we modified a common recognition test, the novel object recognition task, by replacing objects with sandpaper grits at ground level, herein referred to as the novel tactile recognition task (NTR). First, we tested whisker-manipulated mice in this task to determine its reliance on intact whiskers. Then, we tested the HFD mouse in the NTR. Finally, to ensure that deficits in the NTR are due to cognitive impairment and not HFD-induced sensory deficiencies, we tested the whisker sensitivity of HFD mice via the corner test. Our results indicate that the NTR is a whisker dependent task, and that HFD mice exhibit tactile recognition memory impairment, not accompanied by whisker sensory deficits.