Could magnets make the mind grow stronger? In mice at least, stimulating the brain with a magnetic coil appears to promote the growth of new neurons in areas associated with learning and memory. If the effect is confirmed in humans, it might open up new ways of treating age-related memory decline and diseases like Alzheimer’s.
Transcranial magnetic stimulation (TMS) has been used experimentally to treat a range of brain disorders, including depression and schizophrenia, and to rehabilitate people after a stroke. TMS uses a magnetic coil to induce electric fields in the brain tissue – activating or deactivating groups of neurons, although the exact mechanism has remained unknown. One theory was that it aided learning and memory by strengthening brain circuits through a process called long-term potentiation (LTP).
To investigate, Fortunato Battaglia at the City University of New York and his colleagues gave mice TMS for five days, then analysed their brains for evidence of LTP or cell proliferation.
They confirmed that TMS enhanced LTP in all areas of the brain tested, by modifying key glutamate receptors so that they stayed active for longer. The team also saw large increases in the proliferation of stem cells in the dentate gyrus hippocampus. These cells divide throughout life and are now believed to play a crucial role in memory and mood regulation.