Non-Invasive Brain Stimulation as a Method for Mitigation of Spaceflight Neurodegeneration & Associated Cognitive Decline

Evidence is mounting toward the idea that spaceflight stressors decrease cognitive function over time. Current countermeasures focus largely on spacecraft design and environmental modifications, but direct interventions on astronaut physiology could be essential for long-term success. Noninvasive brain stimulation (NiBS) is increasingly used to modulate neuroplasticity and has shown promise for improving cognition in Alzheimer’s disease (AD) and related conditions. NiBS appears plausible as a countermeasure candidate for spaceflight-associated cognitive decline; space-radiation pathways overlap with AD-relevant mechanisms, and AD trials demonstrate rTMS-associated cognitive and plasticity gains. However, the current literature primarily supports plausibility and mechanism overlap rather than direct validation in spaceflight or high-fidelity analogs; there is little evidence for NiBS effects in microgravity; spaceflight-induced brain changes may alter stimulation responses; validated operational protocols and standardized biomarkers are lacking; and long-term safety under extreme environments is uncertain.