Frequency-specific modulations for subcomponents of executive functions in the infra-slow frequency range -A combined O-tDCS and fNIRS study.

BACKGROUNDING: The executive functions (EFs) involve multiple subcomponents including inhibition, updating, and shifting. These subcomponents are mediated by distinct brain networks, each linked to specific neural oscillations. Frequency-specific stimulation is a key approach to achieving precise intervention on different cognitive functions through affecting specific spatiotemporal organizations of brain networks.

OBJECTIVE

We aimed to explore the modulation of different brain networks and EFs' subcomponents by stimulation at frequencies of 0.02 Hz and 0.05 Hz, which are closely linked to whole-brain dynamics.

METHOD: In a randomized, placebo-controlled, cross-over study, we applied anodal oscillatory transcranial direct current stimulation (O-tDCS) to the left DLPFC to investigate the frequency-specific modulation on oxy-hemoglobin (HbO) and offline EF scores (Experiment 1, N = 54), as well as online EF scores (Experiment 2, N = 48).

RESULT: Near the stimulation frequency, brain signals were significantly enhanced. Specifically, an increase in power at 0.02 Hz was associated with enhanced inhibitory function, while an increase in power at 0.05 Hz was linked to decreased updating function. Compared to the sham condition, 0.02 Hz stimulation increases PLV within the frontal lobe, whereas 0.05 Hz increases PLV between the frontal and parietal lobes, indicating the presence of distinct spatiotemporal structures within cognitive-related brain networks.

CONCLUSION

The frequency-specific modulation of O-tDCS on brain networks and EF subcomponents suggests that different EFs are supported by brain networks with specific spatiotemporal architectures, bolstering the spectral fingerprint hypothesis of cognition. The spatiotemporal structure of cognitive-specific brain networks offers novel insights and targets for non-invasive interventions targeting diverse cognitive functions.