Katharina Buczek
“In one patient, who was being treated for obesity, deep brain stimulation caused flashbacks– sudden memories of their childhood and adolescence,” explained Dr. Ana Sofía Ríos, the study’s lead author.
“This led the Canadian researchers to suspect that stimulating this brain region, which was located in the fornix, might also be suitable for treating Alzheimer’s.”
Afterward, scientists from seven international institutions began collaborating on this multicenter study to implant electrodes in patients with AD– specifically in that fornix region.
According to Dr. Ríos, the majority of these patients actually showed no symptom improvement. However, a handful of patients did see considerable benefits.
This ultimately inspired the current research team to conduct this study in hopes of determining the root cause of these benefit variations.
And to do so, the researchers actually compared the exact position of each patient’s implanted electrodes.
More specifically, Professor Horn’s research team specializes in the analysis of high-resolution magnetic resonance brain images, as well as combining these images with computer models in order to pinpoint optimal DBS implantation locations.
The largest obstacle with this stimulation technique, though, lies in the variation of human brains.
“One of the main challenges is that every brain is different– and that’s really important for accurately planting electrodes. When electrodes are placed even a few millimeters off target, it could lead to a lack of benefit for the patient,” Prof. Horn detailed.
This is essentially what occurred for most of the study’s participants. However, using the brain imaging data, the research team was still able to determine the precise location of electrode implantation among the patients that benefited from the therapy.
It was discovered that the optimal stimulation site lies at the intersection of the fornix and stria terminalis– two brain fiber bundles that connect to deeper regions within the brain. Both of these fibers have also been linked to memory function.
