Imagine you’re juggling two different tasks – switching between them quickly can be challenging, especially as you get older. In a study, researchers examined how aging affects the ability to switch between tasks with different rules. They found that older adults faced more difficulties when the context changed from performing just one task to performing multiple tasks without requiring a trial-level switch. This difference in performance was observed as mixing costs. However, when it came to switch costs – rapidly switching back and forth between two simple tasks – older adults were able to compensate for the impairments through enhanced neural activity in certain brain regions. The study involved 71 younger adults and 175 older adults who completed a task-switching experiment while undergoing brain imaging. The findings suggest that aging impacts the specific executive components involved in task switching differently. To delve deeper into this fascinating research, check out the full article!

Aging negatively impacts the ability to rapidly and successfully switch between two or more tasks that have different rules or objectives. However, previous work has shown that the context impacts the extent of this age-related impairment: while there is relative age-related invariance when participants must rapidly switch back and forth between two simple tasks (often called “switch costs”), age-related differences emerge when the contexts changes from one in which only task must be performed to one in which multiple tasks must be performed, but a trial-level switch isn’t required (e.g, task repeat trials within dual task blocks, often called “mixing costs”). Here, we explored these two kinds of costs behaviorally, and also investigated the neural correlates of these effects. Seventy-one younger adults and 175 older adults completed a task-switching experiment while they underwent fMRI brain imaging. We investigated the impact of age on behavioral performance and neural activity considering two types of potential costs: switch costs (dual-task switch trials minus dual-task non-switch trials), and mixing costs (dual-task non-switch minus single-task trials). We replicated previous behavioral findings, with greater age associated with mixing, but not switch costs. Neurally, we found age-related compensatory activations for switch costs in the dorsal lateral prefrontal cortex, pars opercularis, superior temporal gyrus, and the posterior and anterior cingulate, but age-related under recruitment for mixing costs in fronto-parietal areas including the supramarginal gyrus and pre and supplemental motor areas. These results suggest an age-based dissociation between executive components that contribute to task switching.

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