Abstract
BACKGROUND: Conventional 40 Hz gamma stimulation is applied across individuals, potentially overlooking inter-individual neural variability. OBJECTIVE: This study evaluated conversation gamma frequency (CGF)-a personalized gamma frequency derived from task engagement-against the fixed 40 Hz and individual gamma frequency (IGF) derived from auditory responses. METHODS: In Experiment 1, gamma center frequencies were measured under resting, reading, and conversation conditions. In Experiment 2, EEG was used to compare neural entrainment effects across CGF, 40 Hz, and IGF conditions. RESULTS: Conversation gamma frequency stimulation induced stronger neural activation and functional connectivity in the frontal, temporal, and parietal cortices compared to 40 Hz or IGF. Theta-gamma coupling analysis revealed significantly increased phase synchronization under CGF compared to 40 Hz with enhanced connectivity. However, entrainment declined as the frequency difference between CGF, and 40 Hz increased, emphasizing the limitation of fixed-frequency stimulation. CONCLUSION: These findings provide EEG-based mechanistic evidence that individualized gamma stimulation may represent a hypothesis-generating strategy for future neurorehabilitation research in aging and neurodegenerative conditions.