Chemogenetic silencing of hippocampus and amygdala reveals a double dissociation in periadolescent obesogenic diet-induced memory alterations
Neurobiology of Learning and Memory. 2021-02-01; 178: 107354
DOI: 10.1016/j.nlm.2020.107354
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Naneix F(1), Bakoyiannis I(2), Santoyo-Zedillo M(3), Bosch-Bouju C(2), Pacheco-Lopez G(4), Coutureau E(5), Ferreira G(6); OBETEEN Consortium.
Author information:
(1)Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33077, Bordeaux, France; Univ. Bordeaux, CNRS, INCIA, UMR 5287, 33077 Bordeaux, France.
(2)Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33077, Bordeaux, France.
(3)Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33077, Bordeaux, France; Department of Health Sciences, Metropolitan Autonomous University (UAM), Campus Lerma, Mexico.
(4)Department of Health Sciences, Metropolitan Autonomous University (UAM), Campus Lerma, Mexico.
(5)Univ. Bordeaux, CNRS, INCIA, UMR 5287, 33077 Bordeaux, France.
(6)Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33077, Bordeaux, France. Electronic address: .
In addition to numerous metabolic comorbidities, obesity is associated with several adverse neurobiological outcomes, especially learning and memory alterations. Obesity prevalence is rising dramatically in youth and is persisting in adulthood. This is especially worrying since adolescence is a crucial period for the maturation of certain brain regions playing a central role in memory processes such as the hippocampus and the amygdala. We previously showed that periadolescent, but not adult, exposure to obesogenic high-fat diet (HFD) had opposite effects on hippocampus- and amygdala-dependent memory, impairing the former and enhancing the latter. However, the causal role of these two brain regions in periadolescent HFD-induced memory alterations remains unclear. Here, we first showed that periadolescent HFD induced long-term, but not short-term, object recognition memory deficits, specifically when rats were exposed to a novel context. Using chemogenetic approaches to inhibit targeted brain regions, we then demonstrated that recognition memory deficits are dependent on the
activity of the ventral hippocampus, but not the basolateral amygdala. On the contrary, the HFD- induced enhancement of conditioned odor aversion specifically requires amygdala activity. Taken together, these findings suggest that HFD consumption throughout adolescence impairs long-term object recognition memory through alterations of ventral hippocampal activity during memory acquisition. Moreover, these results further highlight the bidirectional effects of adolescent HFD on hippocampal and amygdala functions.