Task-dependent cognitive effects of intermittent theta-burst stimulation across the adult lifespan

Intermittent Theta-Burst Stimulation (iTBS) of the Dorsolateral Prefrontal Cortex (DLPFC) has the potential to enhance cognitive function by inducing long-term potentiation-like effects, modulating cortical excitability and network plasticity. However, the precise effects of iTBS across specific cognitive domains, age groups, and hemispheres remains unclear. Fifty-three adults aged 19-73 years, participated in a within-subject crossover designed study, receiving iTBS to the left and right DLPFC across two sessions, spaced one week apart. Cognitive tasks assessed four cognitive domains of attention, working memory, sequence learning, and inhibition. Processing speed and accuracy were assessed using time and hemisphere as fixed effects and age as a continuous variable in linear mixed effects and Bayesian models. There was an overall slowing of reaction time with age across all tasks. Brain stimulation reduced reaction times in attention and working memory tasks in all participants. Accuracy improved for working memory following iTBS, with a right hemisphere advantage. ITBS of the DLPFC influences cognition in a task-dependent manner. Improvements in attention were not influenced by hemisphere, suggesting a facilitation of top-up processing after DLPFC stimulation. Working memory enhancements were a dominant effect, especially following right hemisphere iTBS stimulation supporting lateralized optimization of visuospatial storage. These findings highlight iTBS as a potential noninvasive tool for cognitive enhancement. Future research should explore the longevity of these effects and their applicability in clinical populations.