Foreign language learning in older adults modifies the pattern of resting-state activity in the medial prefrontal cortex

Background: Foreign language learning (FLL) enhances cognitive functions in older adults, improving memory, attention, and executive functions and potentially delaying cognitive decline. However, the neural mechanisms underlying FLL's benefit on cognition remain unclear, and current methods for studying changes in brain activity are often operator-dependent, potentially missing important effects. This highlights the need for using data-driven techniques. Methods: Resting-state functional Magnetic Resonance Imaging (rs-fMRI) data from 27 older adults (FLL: n = 14; Control: n = 13) were analyzed using a voxel-wise, operator-independent approach, known as fractional Fractional Amplitude of Low-Frequency Fluctuations (fALFF), to identify the FLL-induced longitudinal changes in resting-state neocortical activity. Linear regression analyses further explored links between the longitudinal changes in fALFF and behavioral measures. Results: The between-groups analysis showed that FLL modified the resting-state activity in the medial prefrontal cortex (mPFC), with bilateral increases in the dorsomedial and orbitofrontal regions, overlapping with the medial anterior part of the DMN. A significant correlation was found between the FLL-related changes of fALFF in the mPFC and performance in semantic verbal long-term memory, as assessed by the Babcock Memory Recall Test. Conclusions: FLL alters cortical neural organization by increasing mPFC activity, a putative compensatory phenomenon that counteracts aging-related cognitive decline.