Biology subjects

Ducourneau, E. G.

Publications and source records attributed to Ducourneau, E. G..

3 recordsLinked to original sources

bioRxiv2024

Time-restricted feeding prevents memory impairments induced by obesogenic diet consumption in mice, in part through hippocampal thyroid hormone signaling.

The consumption of calorie-rich diet has adverse effects on short and long-term memory, especially when introduced early in life when the brain is still maturing. Time-restricted feeding (TRF) without calorie restriction has proven to be an efficient strategy to reduce the deleterious effects of diet-induced obesity on metabolism. TRF was also shown to be beneficial to restore long-term memory in Alzheimer rodent models. Here, we provide evidence that four weeks of TRF restore the rhythmicity of some metabolic parameters together with short and long-term memory in mice fed a high fat-high sucrose (HFS) diet since weaning. Hippocampal translatome analyses indicated that impaired memory of mice under ad libitum HFS diet is accompanied by changes in genes associated with thyroid hormone signaling and astrocytic genes involved in the regulation of glutamate neurotransmission. TRF restored the diurnal expression variation of part of these genes and intra-hippocampal infusion of T3, the active form of thyroid hormone, rescued the memory performances of ad libitum HFS diet-fed mice. Thus, TRF demonstrates positive effects on both metabolism and memory in mice fed an obesogenic diet, highlighting this nutritional approach as a powerful tool in addressing obesity and its related comorbidities in mice. The analogous time-restricted eating in humans is an easy to implement lifestyle intervention that should now be tested in obese adolescents with memory alterations.

neuroscience↗

bioRxiv2023

To deliberate, remember; to anticipate, forget: Cognitive deliberation profiles underpinning active forgetting-dependent everyday-like memory performance in young and aged mice.

Recalling a specific past episode that will enable us to decide which action is suited to a given present situation is a core element of everyday life. A wealth of research has demonstrated that such selective remembering is dependent upon a capacity to inhibit or provisionally forget related yet inappropriate memory episodes which could orient behavior in unwilled directions. Everyday-like memory (EdM) refers to this type of common organizational mnemonic capacity, known to deteriorate significantly with age, putatively as a result of decline in the cognitive capacity for selective inhibition or active forgetting. Moreover, this memory retrieval-concomitant active forgetting comes at the cost of genuine amnesic weakening of the inhibited episodes, a phenomenon referred to as retrieval-induced forgetting (RIF). In the present study, we introduce a novel characterization of our previously validated mouse model of EdM in terms of the existing active forgetting and RIF literature. We also introduce novel behavioral analyses of the deliberation processes elicited by EdM challenge and use detailed multi-factorial explorations to reveal how these processes are impacted by age, temporal retention demand, difficulty of EdM challenge, and anticipation of trial outcome. Our observations indicate that deliberation requires remembering while accurate anticipation--in which a critical age-related deficit is also observed--requires active forgetting. Our results represent a significant advance towards unifying our understanding of the neurocognitive processes underpinning everyday-like memory, RIF, mnemonic deliberation, anticipatory function, and how they all are impacted by the physiological ageing process. In parallel, we present preliminary results using a transgenic mouse model which point to a fundamental role for the endocannabinoid system (eCS) in active forgetting and EdM, thereby demonstrating that deeper investigation of previously characterized age-related decline of the eCS should be a pre-clinical priority with a view to developing treatments for age-related decline of EdM function.

animal behavior and cognition↗

bioRxiv2022

Obesogenic diet induces circuit-specific memory deficits in mice

Obesity is associated with neurocognitive dysfunction, including memory deficits. This is particularly worrisome during adolescence, which represents a crucial period for maturation of brain structures, such as the hippocampus which are crucial for cognition. In rodent models, we recently reported that memory impairments induced by obesogenic high-fat diet (HFD) intake during the periadolescent period can be reversed by chemogenetic manipulation of the ventral hippocampus (vHPC). Here, we used an intersectional viral approach in HFD-fed male mice to chemogenetically inactivate specific vHPC efferent pathways to nucleus accumbens or medial prefrontal cortex during memory tasks. We first demonstrated that HFD enhanced activation of both pathways after training and that our chemogenetic approach was effective in normalising this activation. Inactivation of the vHPC-nucleus accumbens pathway rescued HFD-induced deficits in recognition but not location memory. Conversely, inactivation of the vHPC-medial prefrontal cortex pathway restored location but not recognition memory impairments produced by HFD. Either pathway manipulation did not affect exploration, locomotion or anxiety-like behaviour. These findings suggest that HFD intake throughout adolescence impairs different types of memory through overactivation of specific hippocampal efferent pathways and that targeting these overactive pathways has therapeutic potential.

neuroscience↗