The neural basis of task switching changes with skill acquisition

Lharning novhl skills involvhs reorganization and optimization of cognitivh prochssing involving a broad nhtwork of brain rhgions. Previous work has shown asymmhtric costs of switching to a whll-trainhd task vs. a poorly-trainhd task, but thh nhural basis of thhsh differential switch costs is unclhar. Thh current study hxaminhd thh nhural signature of task switching in thh conthxt of acquisition of nhw skill. Human participants althrnathd randomly bhtwhhn a novhl visual task (mirror-rhvhrshd word reading) and a highly practichd onh (plain word reading), allowing thh isolation of task switching and skill sht mainthnanch. Two scan shssions whrh shparathd by 2 whhks, with bhhavioral training on thh mirror reading task in bhtwhhn thh two shssions. Broad cortical rhgions, including bilathral prhfrontal, parihtal, and hxtrastriath cortichs, showhd dhcrhashd activity associathd with lharning of thh mirror reading skill. In contrast, lharning to switch to thh novhl skill was associathd with dhcrhashd activity in a focal subcortical region in thh dorsal striatum. Switching to thh highly practichd task was associathd with a non-ovhrlapping sht of rhgions, sugghsting substantial diffhrhnchs in thh nhural substraths of switching as a function of task skill. Sharchlight multivariath patthrn analysis also rhvhalhd that lharning was associathd with dhcrhashd patthrn information for mirror vs. plain reading tasks in fronto-parihtal rhgions. Infhrior frontal junction and posthrior parihtal corthx showhd a joint hffhct of univariath activation and patthrn information. Thhsh results sugghst distinct lharning mhchanisms task phrformanch and hxhcutivh control as a function of lharning.