TRAINING NON-HARMONIC ALPHA–THETA DYNAMICS VIA EEG NEUROFEEDBACK ENGAGES NEURAL AND NEUROENDOCRINE MECHANISMS OF STRESS REGULATION

Chronic stress is a major risk factor for stress-related psychopathology. Electroencephalography-based neurofeedback training (EEG-NFT) offers an experiential approach to training self-regulation, yet most protocols target isolated oscillatory features and neglect cross-frequency brain dynamics. Emerging evidence suggests that non-harmonic alpha–theta interactions may support decoupled neural states associated with restfulness and stress recovery. Training these dynamics may therefore enhance stress regulation beyond single-frequency approaches. This study examined whether EEG-NFT targeting non-harmonic alpha–theta interactions modulates neural dynamics linked to stress regulation and improves stress-related outcomes.
Eighty healthy adults with mild-to-severe stress were randomly assigned to EEG-NFT or sham training. They completed ten NFT sessions (25 minutes/session) over five weeks while engaging in focused attention mindfulness meditation. Auditory feedback was contingent on non-harmonic alpha–theta ratios in the EEG-NFT group and delivered randomly in the sham training. Outcomes included EEG-based alpha–theta dynamics, self-reported stress-related measures, and salivary oxytocin as a neuroendocrine index of stress-regulatory homeostasis.
Within, but not across, sessions, only the EEG-NFT group showed increases in non-harmonic alpha–theta ratios (p = 0.03). Although questionnaire outcomes showed no robust group-by-time interaction effects, higher trainability led to greater improvements in perseverative thinking and mindfulness skills. Additionally, upon receiving the training, the EEG-NFT group exhibited elevated post-intervention morning oxytocin levels, a hormone implicated in stress buffering. Furthermore, higher baseline mindfulness facilitated learning, whereas greater stress, perseverative thinking, and depressive symptoms impeded learning.
Together, these findings suggest that targeting non-harmonic alpha–theta dynamics via EEG-NFT may engage neurophysiological mechanisms relevant to stress resilience.