In this study, we explored to what extent the hippocampus is altered in middle-aged (6–12 month old) transgenic mice that lack functional leptin receptors and become morbidly obese in adulthood (V-Lep○b-/- mice), corresponding to an animal model of T2D (Wasim et al., 2016; Kleinert et al., 2018). Here, LEPR is linked to type 2 diabetes mellitus.