Cammarata C, DeRosa ED, Anderson AK (2018) Lifespan and cholinergic changes in cognitive flexibility in rats. Neuroscience 2018 Abstracts 512.05 / GGG8. Society for Neuroscience, San Diego, CA.
Summary: The ability to update one’s mental schemas in order respond flexibly and adaptably – i.e. cognitive flexibility – is crucial to navigating a dynamic environment. Proactive interference (PI) is a phenomenon wherein prior memory impedes the formation of new memories for similar information, biasing behavior toward no-longer-relevant schemas. Thus, overcoming PI is an important aspect of cognitive flexibility. PI is exacerbated during aging, and in turn contributes to age-related deficits in cognitive flexibility. In young animals and young adult humans, resolution of PI has been found to rely on neuromodulatory activity via Acetylcholine (ACh), and ACh levels are known to decline in aging, however it has yet to be demonstrated whether these age-related changes in ACh directly contribute to age-related increase in PI. Here, we first compared PI resolution in middle-aged (13 months, n = 8) and old (23 months, n= 11) male Long Evans rats, finding that old animals were more inefficient in resolving PI when compared to the middle-aged animals. Furthermore we performed cholinergic deafferentation, with the immunotoxin 192-IgG saporin (SAP; 0.2 µl of 0.3 µg/µl dissolved in sterile phosphate buffered sale in each of four locations targeting bilateral anterior and posterior basal forebrain), in our older rats (N= 5 SAP and N=6 Sham) which had no effect on the floor performance of older rats. This suggests that the inability to resolve PI seen in the aged rats may be due to already-depleted levels of ACh. We are currently collecting local field potential data in the prelimbic and posterior parietal cortices in behaving older and younger rats and will combine this with central administration of muscarinic cholinergic pharmacology to continue to examine age-related changes in the cortical dynamics that support cognitive flexibility. Based on prior findings in our laboratory examining similar attentional flexibility, we predict the young animals will demonstrate increased beta band LFP activity in the posterior parietal cortex, and potentially increased beta coherence between prefrontal and posterior parietal cortices, related to successful resolution of PI. We expect such activity to be mitigated by cholinergic antagonists and in the older animals.
Related Products: 192-IgG-SAP (Cat. #IT-01)