Abstract
In the present study, we aimed at examining selective neural changes after task-switching training in old age by not only considering the spatial location but also the timescale of brain activation changes (i.e., sustained/block-related or transient/trial-related timescales). We assigned a sample of 50 older adults to a task-switching training or an active single-task control group. We administered two task paradigms, either sensitive to transient (i.e., a context-updating task) or sustained (i.e., a delayed-recognition working-memory task) dynamics of cognitive control. These dynamics were captured by utilizing an appropriate event-related or block-related functional magnetic resonance imaging design. We captured selective changes in task activation during the untrained tasks after task-switching training compared to an active control group. Results revealed changes at the neural level that were not evident from only behavioral data. Importantly, neural changes in the transient-sensitive context updating task were found on the same timescale but in a different region (i.e., in the left inferior parietal lobule) than in the task-switching training task (i.e., ventrolateral PFC, inferior frontal junction, superior parietal lobule), only pointing to temporal overlap, while neural changes in the sustained-sensitive delayed-recognition task overlapped in both timescale and region with the task-switching training task (i.e., in the basal ganglia), pointing to spatio-temporal overlap. These results suggest that neural changes after task-switching training seem to be critically supported by the temporal organization of neural processing.
Highlights
One core component of executive control is the ability to schedule and sustain multiple goals at the same time or in rapid alternation
Neural overlap of training group differences in trained and untrained tasks Importantly, for both transient and sustained changes, we further aimed to examine whether any selective changes would be based on spatial, temporal, or spatio-temporal overlap with activation changes found previously in the task-switching training task
For the delayed-recognition task, we obtained a similar pattern of results: We found significant changes in behavioral performance from pre- to posttest on the level of error rates (F(2,80) = 8.02, p = 0.00, ηp2 = 0.17; not on the level of latencies, p = 0.47) indicating a decrease of WM maintenance error costs (F(1,40) = 20.05, p = 0.00, ηp2 = 0.33), albeit not of WM scheduling error costs (p = 0.31)
Summary
One core component of executive control is the ability to schedule and sustain multiple goals at the same time or in rapid alternation. Recent neuroimaging studies suggest fundamental changes at the neural level underlying this age-related decline in executive control. In our recent study (Dörrenbächer et al, 2017a,b), we already examined such neural plasticity in brain activity dynamics after task-switching training in older adults during the task-switching task. We applied a hybrid event-related-/block fMRI design (Visscher et al, 2003) to investigate spatial and temporal dynamics of neural mechanisms underlying changes after training in task switching compared to a singletask active control regime in older adults. Our results revealed spatio-temporal interactions in training-induced neural changes These spatially dissociable changes of trial- versus block-related brain activation were both related to improvement of task switching behavior. A second important insight of that study was that neural mechanisms might reveal more subtle training-induced effects that we may not become aware of from only examining the behavioral data
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
