Modulating Mind and Body: Effects of tDCS and Probiotics on Cognitive-Behavioral and Autonomic Outcomes in Overweight Adults

This study investigates the comparative effects of transcranial direct current stimulation (tDCS) targeting the ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC), alongside probiotic supplementation, on cognitive-behavioral and autonomic outcomes in 58 overweight adults (BMI ≥ 25 kg/m²). Conducted over a controlled intervention period, participants were randomized into four groups: vmPFC tDCS (n = 14), dlPFC tDCS (n = 14), probiotics (n = 15), and sham control (n = 15). Primary outcomes included impulsivity (UPPS-P), nutritional attitudes (EAT-26), self-control (Tanji), general health (GHQ-28), food choice, risky decision-making (BART), and heart rate variability (HRV) components (e.g., HF_power, RMSSD). Results revealed that vmPFC tDCS significantly reduced impulsivity (p = 0.019, η² = 0.170) and improved nutritional attitudes (p = 0.031, η² = 0.152), while enhancing parasympathetic activity (HF_power, p = 0.010). Probiotic supplementation increased RMSSD (p = 0.013), indicating improved autonomic balance, but showed no cognitive-behavioral effects. In contrast, dlPFC tDCS and the control group exhibited no notable changes (p > 0.05). These findings highlight vmPFC tDCS as a promising intervention for modulating reward-related behaviors and autonomic function in obesity, with probiotics offering potential physiological benefits. The study bridges neuromodulation and gut-brain axis research, suggesting tailored approaches for managing obesity’s cognitive and physiological underpinnings.