Neural Sources of Multitasking Interference Revealed in a Complex Continuous Multitasking Environment

Our brains are limited in their ability to process all information it receives thus requiring cognitive control mechanisms to modulate information and responses. Previous attempts to characterize multitasking costs in the neuropsychological literature largely study two-discrete-task paradigms. For my project, we studied the use of a complex continuous task punctuated by a second discrete task, more comparable to real-world tasks as well as the possibility that these well-characterized discrete approaches may be missing neural mechanisms critical to multitasking costs. In the first study, we use this paradigm's advantages to study embedded stimuli whose inter-task timing of stimuli are jittered in a controlled way to replicate many of the effects studied in previously the multitasking literature to demonstrate a novel perceptual bottleneck of interference in addition to the well-characterized response bottleneck. In the second study, this task was taken into the scanner to study the multitasking versus single-tasking differences, using a perceptually identical environment to control for potential perceptual sources of dual-tasking. This study demonstrated the superior parietal lobule, a region previously characterized for cognitive control over motor preparation as well as multitasking to not only show differential activity between the conditions, but to demonstrate individual activity differences correlating with individual multitasking performance costs. The significance of this finding is that we identified a specific control region relevant to individual multitasking costs in our complex continuous tracking paradigm. The studies above (in combination with its validation as a training platform (Anguera et al., 2013)) identifies our novel task as a robust, complex neurocognitive platform to study human performance deficits. We replicate previously characterized timing-dependent phenomena (i.e. PRP effect) and dual-tasking neural control centers (superior parietal lobule) without the need for the traditionally constrictive laboratory demands of response ordering and with a higher user engagement in a more real-world relevant task