Computational model showed categorization system-switching deficits in typical aging and Parkinson's disease

Past research had shown that older adults are often worse at adapting to shifting situational demands when compared to younger adults. The work from Hélie and Fansher (2018) explored the deficits in categorization system-switching in older adults and patients with Parkinson's disease to see if they can switch between different categorization systems flexibly on a trial-by-trial basis. We fitted a computational model that focuses on the switching mechanism with spiking neurons to simulate neuronal activity of the hyperdirect pathway of the basal ganglia to the data from Hélie and Fansher (2018) to determine the possible factors contributing to the deficits in system switching. The model simulates the gating of the response transmission from the modelfree learning system (in the striatum) for action selection. The simulation results suggest that poor system-switching capability may be related to lower tonic dopamine level, and higher susceptibility to proactive interference.