Abstract
Humans show striking limitations in information processing when multitasking, yet can modify these limits with practice. Such limitations have been attributed to the capacity of a frontal-parietal network, but recent models of decision-making implicate a striatal-cortical network. We adjudicated these accounts by implementing a dynamic causal modelling (DCM) analysis of a functional magnetic resonance imaging (fMRI) dataset, where 100 participants completed a multitasking paradigm in the scanner, before and after engaging in a multitasking (N=50) or an active control (N=50) practice regimen. We observed that multitasking costs, and their practice related remediation, are best explained by modulations in information transfer between the striatum and the cortical areas that represent stimulus-response mappings. Neither multitasking nor practice modulated direct frontal-parietal connectivity. Our results support the view that limits in cognitive capacity are striatally driven, and moderated by the interplay of information exchange from the putamen to the pre-supplementary motor area.
