136. Region-specific differences of high-fat diet induced cognitive impairments between the amygdala and hippocampus

Increased dietary intake of fat is linked with obesity and obesity-associated comorbidities including cognitive and behavioral impairments. We examined the impact of a high-fat diet (HFD) feeding (60% kcals from fat) versus a low-fat diet (LFD) feeding (10% kcals from fat) using novel object location (NOL), a hippocampal-sensitive task, and novel object recognition (NOR) and elevated zero maze, amygdala-sensitive tasks. Mice were fed a LFD or HFD for 6 weeks starting at 3–4 weeks of age. Cohorts were trained for a 24-h period in both memory tasks. NOR was impacted after 1 week on HFD but was recovered after 6 weeks on diet. In the elevated zero maze, 3 weeks of HFD caused impaired open arm exploration that was recovered by 6 weeks. Conversely, NOL was not impacted at 1 week on diet but showed sustained impairment thereafter. The observed NOR and elevated zero maze recovery after 6 weeks on diet suggests that the amygdala can overcome high-fat diet associated impairments. However, the hippocampus appears susceptible to prolonged HFD induced cognitive impairment. These results demonstrate region-specific differences of HFD feeding on cognition.