The cognitive and neuroanatomical correlates of multitasking

Patients who show the "strategy application disorder" can show deficits res tricted to situations requiring multitasking, but the precise neuroanatomic al and cognitive correlates of this problem have been rarely investigated. In this study, 60 people with circumscribed cerebral lesions and 60 age- an d IQ-matched controls were given a multitasking procedure which allowed con sideration of the relative contributions of task learning and remembering, planning, plan-following and remembering one's actions to multitasking perf ormance. Lesions to the left posterior cingulate and forceps major legions gave deficits on all measures except planning. Remembering task contingenci es after a delay was also affected by lesions in the region of the left ant erior cingulate, and rule-breaking and failures of task switching were addi tionally found in people with lesions affecting the medial and more polar a spects of Brodmann's areas 8, 9 and especially 10. Planning deficits were a ssociated with lesions to the right dorsolateral prefrontal cortex (RDLPFC) . A theory of the relationships between the cognitive constructs underpinni ng multitasking was tested using structural equation modelling. The results suggest that there are three primary constructs that support multitasking: retrospective memory, prospective memory, and planning, with the second tw o drawing upon the products of the first. It is tentatively suggested that the left anterior and posterior cingulates together play some part in the r etrospective memory demands, while the prospective memory and planning comp onents make demands on processes supported by the left areas 8, 9 and 10 an d the RDLPFC respectively. (C) 2000 Elsevier Science Ltd. All rights reserv ed.