ANDRZEJ KRAUZEWhen something goes wrong with neurons located deep in the brain, options for treatment are limited. Directly stimulating the neurons can be effective, but cutting through brain tissue to implant the necessary electrodes is risky. And magnetic or electrical pulses applied to the skull only reach the brain’s outermost regions. But the highly networked nature of the brain presents another possibility: noninvasively alter the activity of the neurons at the brain’s surface to indirectly affect the deeper brain regions they’re connected to.
Following this logic, neuroscientist Joel Voss’s group at the Northwestern University Feinberg School of Medicine and colleagues performed repetitive transcranial magnetic stimulation (rTMS) on subjects who then underwent memory testing. The researchers targeted rTMS to an area at the surface of each participant’s brain that they had determined to have rich and active connections to the more deeply positioned left hippocampus, which is known to be necessary for associative memory. For five days in a row, participants received 1,600 magnetic pulses to the left side of the head, a process that took 20 minutes and produced only a mild tapping sensation on the scalp. Before, during, and after the week of rTMS, the researchers tested the participants’ ability to recall a word paired with a ...
