Altered intertemporal choice with age is only partially mediated by prefrontal cortex Decline of prefrontal cortical-mediated executive functions but attenuated delay discounting in aged Fischer 344 x Brown Norway hybrid rats

Publication date: Available online 5 September 2017
Source:Neurobiology of Aging
Author(s): Caesar M. Hernandez, Lauren M. Vetere, Caitlin A. Orsini, Joseph A. McQuail, Andrew P. Maurer, Sara N. Burke, Barry Setlow, Jennifer L. Bizon
Despite the fact that prefrontal cortex (PFC) function declines with age, aged individuals generally show an enhanced ability to delay gratification, as evident by less discounting of delayed rewards in intertemporal choice tasks. The current study was designed to evaluate relationships between two aspects of PFC-dependent cognition (working memory and cognitive flexibility) and intertemporal choice in young (6 mo.) and aged (24 mo.) Fischer 344 x Brown-Norway F1 hybrid rats. Rats were also evaluated for motivation to earn rewards using a progressive ratio task. As previously reported, aged rats showed attenuated discounting of delayed rewards, impaired working memory, and impaired cognitive flexibility compared to young. Among aged rats, greater choice of delayed reward was associated with preserved working memory, impaired cognitive flexibility, and less motivation to work for food. These relationships suggest that age-related changes in PFC and incentive motivation contribute to variance in intertemporal choice within the aged population. Cognitive impairments mediated by PFC are unlikely, however, to fully account for the enhanced ability to delay gratification that accompanies aging.



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