Magnetic sparks for the brain: A new frontier in the battle against Alzheimer’s

Alzheimer’s disease affects millions worldwide and still lacks a curative treatment. Existing medications mostly target amyloid plaques and tau proteins, but they fail to halt cognitive decline. Neuroscientists now agree that the real casualties of this disease are the synapses the microscopic connections between neurons that gradually vanish, leading to memory loss. Restoring synaptic plasticity the brain’s ability to reshape its neural connections has therefore become a top research priority.

One technique is increasingly gaining attention: repetitive transcranial magnetic stimulation (rTMS). Already in use for psychiatric and certain neurological conditions, this non-invasive method might help rejuvenate brain networks damaged by Alzheimer’s. A study published in Neurophotonics (May 2025) by Barbora Fulopova (Queensland Brain Institute, University of Queensland), William Bennett, and Alison J. Canty (Wicking Dementia Research and Education Centre, University of Tasmania) offers compelling evidence in animal models.

Real-Time imaging of the brain’s response to rTMS

To assess the effects of stimulation, the researchers worked with genetically modified mice that develop amyloid plaques similar to those seen in Alzheimer’s patients. These mice, already in advanced stages of the disease, were compared to healthy controls. Using fluorescent labeling, the team was able to observe synapses in real time under a microscope.

They focused on two types of synaptic connections: “terminal boutons” at the tips of axons, and “en passant boutons,” which appear as small bulges along the nerve fibers. After several days of baseline observation, a single session of magnetic stimulation was delivered using a small coil placed on the skull. This coil emitted brief pulses designed to alter neuronal activity. The goal was clear: to determine whether rTMS could reignite the brain’s capacity for synaptic remodeling.

🔗 Explore further: The eternal memory: When love defies forgetting

Magnetism reawakens dormant synapses

The findings are striking. Before stimulation, the diseased mice had a similar number of synapses as healthy ones, but their synapses were far less dynamic. The connections appeared frozen, unable to adapt a hallmark of impaired plasticity in Alzheimer’s.

After stimulation, changes emerged. The en passant boutons remained stable, but the terminal boutons showed renewed vitality. Their turnover rate measured by the appearance and disappearance of synapses over two days significantly increased. In fact, the diseased mice’s synaptic dynamics returned to levels seen in healthy brains. In short, rTMS temporarily restored flexibility to these neural connections.

This doesn’t mean the total number of synapses increased. Rather, it suggests that their adaptability was reactivated. The selective effect limited to certain synapse types indicates that rTMS may target specific cortical circuits involved in memory and cognition.

🔗 Discover more: Alzheimer’s puzzle through the lens of mathematics

What this means for future treatments

These results are not a cure, but they open an exciting avenue. A single session of rTMS was enough to restore synaptic plasticity, at least briefly, in a diseased brain. Repeated sessions could potentially prolong the effect and even translate into memory improvements over time. The researchers remain cautious: the study involved a small number of animals and focused on one specific brain region. The effect was temporary, and its impact on cognitive function was not directly tested.

Nevertheless, the progress is significant. It demonstrates that the brain retains a capacity for reorganization even in the face of Alzheimer’s and that this potential can be harnessed through a safe and already established technique. For neuroscience, it reinforces the central role of synapses in the disease. For medicine, it suggests a new therapeutic path worth exploring. And for society, it brings a spark of hope: that magnetic stimulation might one day complement current treatments and enhance patients’ quality of life.