Novel object recognition is not affected by age despite age-related brain changes

Abstract

Age-related memory impairments show a progressive decline across lifespan. Studies have demonstrated equivocal results in biological and behavioral outcomes of aging. Thus, in the present study we examined the novel object recognition task at a delay period that has been shown to be impaired in aged rats of two different strains. Moreover, we used a strain of rats, Fisher 344XBrown Norway, which have published age-related biological changes in the brain. Young (10 months old) and aged (28 months old) rats were tested on a standard novel object recognition task with a 50 minutes delay period. The data showed that young and aged rats in the strain we used performed equally well on the novel object recognition task and that both young and old rats demonstrated a righthanded side preference for the novel object. Our data suggested that novel object recognition is not impaired in aged rats although both young and old rats have a demonstrated side preference. Thus, it may be that genetic differences across strains contribute to the equivocal results in behavior, and genetic variance likely influences the course of cognitive aging.

Individual differences in age-related neurocognitive outcomes: within-subject assessment of memory for odors

“…It has been demonstrated that aged rodents are not impaired in their ability to recognize and preferentially explore novel objects when delays between sampling and testing are short (2–15 min) ( Burke et al, 2010 ; Bergado et al, 2011 ; Arias-Cavieres et al, 2017 ) but are impaired relative to young adult animals with long-term delays ( Cavoy and Delacour, 1993 ; Lukaszewska and Radulska, 1994 ; Pietá Dias et al, 2007 ; Burke et al, 2010 ; Aktoprak et al, 2013 ; Arias-Cavieres et al, 2017 ; Weiler et al, 2021 ), similar to animals with hippocampal inactivation ( Hammond et al, 2004 ), perirhinal lesions ( Ennaceur and Aggleton, 1997 ; Kesner et al, 2001 ), and aged human subjects ( Davis et al, 2003 ). This suggests that the observed age-related memory impairment is due to memory load rather than impaired ability to perceive differences between objects.…”