Human life expectancy is gradually increasing while healthy life expectancy tends to stagnate. Aging is accompanied by a multitude of impairments of brain functions such as attention, memory and all the executive functions that guarantee the person’s cognitive autonomy. Among the struggles against degenerative diseases, those against Alzheimer’s disease are becoming a real social challenge, particularly through early detection of its pre-symptomatic manifestations. With this in mind, the development of preclinical animal models on which therapeutic strategies can be developed is becoming a crucial objective of research on ageing. The team led by P. Girard at CerCo

was able to highlight that a small South American monkey, the marmosets (or white tailed marmosets), is an extremely relevant model of non-human primate for studying brain aging. Indeed, this small monkey has the advantage of having a short lifespan of about ten years, thus constituting an accelerated model of human ageing and providing a time scale adapted to laboratory studies. While the marmosets have become a model of choice for the study of perceptual or motor functions, to date no French team has addressed the cognitive abilities of this primate and its alterations over the course of a lifetime and none in the world has determined the key periods of its cognitive decline. The work of Amirouche Sadoun and Pascal Girard has consisted in testing the abilities of monkeys of different ages in several tasks that are affected in humans in the event of pathological cognitive aging. The monkeys, tested without capture or constraint in their social group, were confronted with tests of shape memorization and short-term spatial working memory. The researchers were able to demonstrate very marked deficits in elderly monkeys and, above all, they were able to show, in a manner similar to that observed in humans, the presence of individuals who, although not yet considered to be aging, have abnormal deficits, signs of pathological aging. These results, recently published in a leading journal in the field, highlight the marmoset model in the study of brain aging and open up promising investigative horizons in which all preclinical research tools can be used, from molecular imaging for the development of prognostic markers to therapeutic trials. http://www4.cnrs-dir.fr/insb/recherche/parutions/articles2018/p-girard.html