TMS improves memory. According to a study published in the Aug. 29 issue of the journal Science, “electrically stimulating a portion of the brain that coordinates the way the mind works can enhance memory and improve learning.”
The researchers used Transcranial Magnetic Stimulation (TMS) to indirectly stimulate activity in the hippocampus, a key part of the brain involved in the storage of memory.
Those of you who have some understanding of how TMS works may be surprised that TMS stimulation can affect function of the hippocampus. After all, TMS stimulation affects only the superficial part of the brain (the neocortex) and the hippocampus is part of the limbic brain, the deepest part of the brain.
The authors hypothesized that stimulation of the lateral parietal cortex would affect the function of the hippocampus, “on the basis of hypothesized interactions between hippocampus and lateral parietal cortex in memory as well as robust functional connectivity between these regions …”
The authors then demonstrated that this hypothesized connection between the lateral parietal cortex and the hippocampus was real by using functional MRI scanning to show that stimulation of the lateral parietal cortex specifically enhanced activity in circuits in the hippocampus.
Then they tested whether this allowed them to affect hippocampal function by stimulating the parietal cortex.
The study of transcranial magnetic stimulation (TMS) performed on 16 people found that “five days of stimulation for 20 minutes improved their performance on a memory test, while no benefit was seen after they got a sham stimulation.”
“After about three days, the stimulation resulted in improved memory, and [participants] got about 30% more associations right with stimulation than without.” In addition, “the MRIs showed that the brain regions became more synchronized by the TMS.”
Researchers are now “planning a study of TMS in older adults in the early stages of memory loss.”
This study not only shows that the hippocampus plays a central role in human memory but opens a window on an exciting new approach to enhancing memory in humans using a safe and non-invasive brain stimulation technique.
- J. X. Wang, L. M. Rogers, E. Z. Gross, A. J. Ryals, M. E. Dokucu, K. L. Brandstatt, M. S. Hermiller, J. L. Voss. Targeted enhancement of cortical-hippocampal brain networks and associative memory. Science, 2014; 345 (6200): 1054 DOI:10.1126/science.1252900