Neural and behavioral effects of adaptive semantic long-term memory retrieval training: A task fMRI study

Semantic long-term memory retrieval (SLTMR) is a core component of higher-order cognition. Previous studies suggest that targeted cognitive training can enhance SLTMR performance; however, the underlying neural mechanisms remain unclear. In this study, 58 participants were randomly assigned to either an adaptive training group or an active control group. The training group completed 18 sessions of adaptive Posner task-based training, while the control group performed a non-adaptive variant. Pre- and post-session assessments included semantic retrieval tasks (Sort and Posner tasks) and far-transfer tasks (Stroop, switching, updating, reading fluency, and Raven), with functional MRI acquired during the Sort task. Results showed that the training group exhibited significant improvements in both the training and near-transfer tasks, with faster reaction times in the categorization and Posner tasks. Far-transfer tasks showed a main effect of training sessions but no significant group by session interactions. fMRI analyses revealed training-specific increases in activation of the left superior temporal gyrus (temporal pole) during semantic retrieval. These findings indicate that SLTMR training selectively enhances domain-specific semantic retrieval and is associated with training-related functional plasticity in a key semantic region, while evidence for effects on broader cognitive domains was more limited in the present dataset.