by Jennifer Bolton and Serena Smith, TMS Clinicians at SeattleNTC
Transcranial magnetic stimulation (TMS), a noninvasive method of brain stimulation, has recently been shown to enhance neural pathways in the brain that are associated with memory function. In memory processing, superficial regions of the brain, such as the lateral-parietal cortex, connect to deeper memory control centers, such as the hippocampus. Because TMS can stimulate only the outer few centimeters of the human cortex, the lateral-parietal cortex has been identified as a target area over which TMS could be used to affect deeper brain structures or regions involved in memory.
In a study by Wang et. al, healthy subjects receiving rTMS to the lateral-parietal region of the brain were compared to subjects receiving sham treatments. Sham treatment mimics the feeling of rTMS without stimulating the brain. After 5 consecutive days of rTMS, functional magnetic resonance imaging (fMRI) of the group receiving “real” rTMS indicated increased connectivity between the lateral-parietal region and the hippocampus. This increased regional brain connectivity correlated with improvements on associative memory tests. Differences in regional brain connectivity or associative memory test scores were not seen in the sham group. These results support the theory that rTMS given over superficial brain regions can have downstream effects on deeper regions of the brain more directly involved in memory funtions, resulting in significant improvements in memory testing. rTMS shows much promise as a future treatment of memory dysfunction, however, further studies involving patients with disease pathology are needed.
Wang JX, Rogers LM, Gross EZ, et al. Targeted enhancement of cortical-hippocampal brain networks and associative memory. Science. Published online August 29 2014
Links To news articles about the study:
Magnetic brain stimulation treatment shown to boost memory. The Guardian, August 28 2014
Electrical brain stimulation ‘boosts memory’. BBC News, August 29 2014
Magnetic pulse to head could improve memory of dementia sufferers. The Daily Telegraph, August 28 2014