Characterisation of behaviours relevant to apathy syndrome in the aged male rat

Behav Brain Res. 2024 Apr 1:114977. doi: 10.1016/j.bbr.2024.114977. Online ahead of print.ABSTRACTApathy is a complex psychiatric syndrome characterised by motivational deficit, emotional blunting and cognitive changes. It occurs alongside a broad range of neurological disorders, but also occurs in otherwise healthy ageing. Despite its clinical prevalence, apathy does not yet have a designated treatment strategy. Generation of a translational animal model of apathy syndrome would facilitate the development of novel treatments. Given the multidimensional nature of apathy, a model cannot be achieved with a single behavioural test. Using a battery of behavioural tests we investigated whether aged rats exhibit behavioural deficits across different domains relevant to apathy. Using the effort for reward and progressive ratio tasks we found that aged male rats (21-27 months) show intact reward motivation. Using the novelty supressed feeding test and position-based object exploration we found aged rats showed increased anxiety-like behaviour inconsistent with emotional blunting. The sucrose preference test and reward learning assay showed intact reward sensitivity and reward-related cognition in aged rats. However, using a bowl-digging version of the probabilistic reversal learning task, we found a deficit in cognitive flexibility in aged rats that did not translate across to a touchscreen version of the task. While these data reveal important changes in cognitive flexibility and an...
Source: Brain Research - Category: Neurology Authors: Source Type: research