Meal scheduling corrects obesogenic diet induced-uncoupling of cortico-hippocampal activities supporting memory.

BACKGROUND

Highly caloric food consumed around the clock perturbs the metabolism and cognitive functioning. We hypothesised that obesogenic food could alter neuronal representations of memory depending on the feeding-fasting cycle.

METHODS

We tracked memory performance, dendritic spine dynamics and neuronal representations of memory in C57Bl6J mice fed obesogenic food ad libitum from peri-adolescence. We aimed to correct energy rich diet-induced plasticity deficits and cognitive impairment with time-restricted feeding in males and females. We further used chemogenetics, pharmacology and knock-in mice to investigate functional correlates underlying diet-induced neurocognitive impairments.

FINDINGS: We found that changes in the feeding-fasting cycle reverted the effects of ad libitum obesogenic food on memory impairment in both sexes (n = 55, p = 0.003). Concurrently, it also corrected the increased dendritic spine maintenance and neuroactivity in hippocampus and the decreased spine maintenance and activity in parietal cortex (n = 48, p < 0.005). Bi-directional effects in cortex and hippocampus mediated by glucocorticoid signalling are causal to behavioural changes (n = 91, p = 0.0008), and scaling hippocampal with cortical activities restored memory in mice fed obesogenic food (n = 44, p = 0.02).

INTERPRETATION: These results indicate that meal scheduling is a promising approach to confront glucocorticoid signalling bias and memory deficits caused by obesogenic food.

FUNDING: Agence Nationale de la Recherche (ANR-21-CE14-0086), Fondation pour la Recherche sur le Cerveau (FRC).