Experimental and computational study of 40 Hz low-field magnetic stimulation modulating neural activity and pathology...

Low-field magnetic stimulation (LFMS) is a non-invasive, subthreshold neuromodulation technique that has demonstrated rapid mood-enhancing effects in depression. Given that depression often presents as an early symptom of Alzheimer's disease (AD), and both conditions are classified as neuropsychiatric disorders, the potential of LFMS as an intervention for AD and its underlying mechanisms remains underexplored.

This study employed a randomized controlled design using 7-month-old APP/PS1 transgenic Alzheimer's disease mice and C57BL/6 J wild-type mice. The stimulation group received low-field magnetic stimulation at 40 Hz and 10 mT twice daily for 0.5 h each session, while the sham group was exposed to the same conditions without activation. The intervention lasted for 14 consecutive days. Electrophysiological activity and Aβ₄₂ deposition were assessed via local field potential recordings and immunofluorescence. Additionally, finite element simulations and computational neural network modeling were performed to analyze the relationship between LFMS-induced electric fields and neuronal responses.

The results showed that 40 Hz LFMS significantly enhanced gamma oscillations during sharp-wave ripples in the AD mouse model and reduced hippocampal Aβ₄₂ deposition by 2.7 %. Finite element simulations indicated that under experimental conditions, LFMS induced a peak electric field of approximately 0.3 V/m in the mouse brain. Computational modeling further demonstrated that this subthreshold pulsed electric field modulated neuronal spike timing, increasing the phase-locking value by 0.044, thereby regulating neuronal activity.

40 Hz LFMS entrained endogenous gamma oscillations, significantly enhanced gamma power and reduced Aβ₄₂ pathological deposition, offering a safe and effective neuromodulation strategy for Alzheimer's disease.