Altered activity in two brain regions could explain why older animals struggle to adapt to changes in their environment.
Previous research has shown that a circuit connecting the thalamus and striatum helps animals to adapt their previous learning to a change in conditions. Jesus Bertran-Gonzalez at the University of Queensland in Brisbane, Australia, and his colleagues found that old mice showed weaker connections from the thalamus to the striatum, and had altered electrical properties in certain striatal neurons, compared with young mice. The team trained mice to press one lever to receive a preferred food and another for a non-preferred food; when researchers reversed these associations, old mice, as well as young mice with damage to this circuit, had trouble adapting their actions to the new rules.
The authors suggest that defects in this pathway impair an ageing animal's ability to integrate new and existing information when deciding how to act.
Neuron http://dx.doi.org/10.1016/j.neuron.2016.03.006 (2016)