Acceleration-Dependent Effects of Vibrotactile Gamma Stimulation on Cognitive Recovery and Cholinergic Function in a Scopolamine-Induced Neurotoxicity Mouse Model

Abstract

Background: Alzheimer's disease is a progressive neurodegenerative disorder characterized by cognitive decline and memory loss. Gamma (gamma) oscillations are closely linked to learning and memory, and recent interest has grown around Gamma ENtrainment Using Sensory stimulation (GENUS) as a non-invasive neuromodulation strategy. However, the therapeutic impact of vibrotactile gamma stimulation under varying physical parameters such as acceleration remains underexplored. Methods: Differentiated SH-SY5Y cells were treated with amyloid-beta (A beta) and exposed to vibrotactile stimulation at 2.2 or 4.0 m/s2. In vivo, male C57BL/6N mice (7 weeks old, 35 g) were administered scopolamine to induce neurotoxicity and randomly assigned to sham, scopolamine, donepezil, or vibrotactile stimulation groups (n = 10 each). Behavioral tests, biochemical assays, Western blotting, and immunohistochemistry were performed to evaluate cognitive function, oxidative stress, cholinergic activity, synaptic plasticity, and neuroinflammation. Results: In vitro, SH-SY5Y cells exposed to amyloid-beta (A beta) were treated with vibrotactile stimulation, resulting in enhanced neuronal marker expression at 2.2 m/s2. In vivo, mice receiving stimulation at 2.2 m/s2 showed improved cognitive performance, reduced oxidative stress, restored cholinergic function, suppressed neuroinflammation, and enhanced synaptic plasticity. Mechanistically, these effects were associated with activation of the AKT/GSK3 beta/beta-catenin pathway. Conclusions: Our findings demonstrate that vibrotactile gamma stimulation at 2.2 m/s2 exerts greater therapeutic efficacy than higher acceleration, highlighting the importance of optimizing stimulation parameters. This work supports the potential of acceleration-tuned, non-invasive GENUS-based therapies as effective strategies for cognitive recovery in neurodegenerative conditions.