Researchers at University of Iowa Health Care reported in Nature Communications that noninvasive transcranial magnetic stimulation can reliably engage and modulate activity in the hippocampus, a deep brain region central to memory and emotion that has generally been considered beyond the reach of surface coils.
The critical variable was personalization. In four neurosurgical patients with implanted electrodes whose stimulation sites were tailored using their own resting-state functional MRI connectivity patterns, the team observed clear activity changes in the hippocampus. In four patients stimulated without that personalized targeting, no robust changes appeared. A larger arm of the study using concurrent TMS-fMRI in 79 healthy participants found that stronger connectivity between the stimulation site and the hippocampus predicted stronger responses.
The work was led by Jing Jiang, PhD, assistant professor of pediatrics at the University of Iowa.
The clinical implication is less about reaching new brain regions than about how targeting is chosen. Most TMS delivered in clinics today is aimed using scalp measurements rather than individual imaging. This study adds to a growing body of evidence — alongside connectivity-guided protocols such as SAINT — that personalized targeting materially changes what stimulation actually does in the brain, and it opens a plausible path toward noninvasive treatment of conditions involving deeper structures, including Alzheimer’s disease, PTSD, and anxiety.
Source
Reporting based on coverage from Medical Xpress / Nature Communications. This article is editorial summary intended for general information; it is not medical advice.
