Brain Stimulation May Enhance Memory
The investigators recruited 25 neurosurgical patients undergoing clinical monitoring for epilepsy to participate in sessions of a delayed free-recall memory task. Subjects completed at least three record-only sessions of free recall with which the researchers trained a system to use intracranial EEG activity during encoding to predict the likelihood of later word recall.
During subsequent sessions, if the system predicted that the probability of recall was less than 0.5, it triggered 500 ms of bipolar stimulation. The researchers found that lateral temporal cortex stimulation increased the relative probability of item recall by 15%.
“By developing patient-specific, personalized, machine-learning models, we could program our stimulator to deliver pulses only when memory was predicted to fail, giving this technology the best chance of restoring memory function,” said Michael Kahana, PhD, Professor of Psychology at the University of Pennsylvania and principal investigator of the Restoring Active Memory program. “This [approach] was important, because we knew from earlier work that stimulating the brain during periods of good function was likely to make memory worse.”
—Jake Remaly
Suggested Reading
Ezzyat Y, Wanda PA, Levy DF, et al. Closed-loop stimulation of temporal cortex rescues functional networks and improves memory. Nat Commun. 2018;9(1):365.
Hampson RE, Song D, Robinson BS, et al. Developing a hippocampal neural prosthetic to facilitate human memory encoding and recall. J Neural Eng. 2018;15(3):036014.
Inman CS, Manns JR, Bijanki KR, et al. Direct electrical stimulation of the amygdala enhances declarative memory in humans. Proc Natl Acad Sci U S A. 2018;115(1):98-103.
Kucewicz MT, Berry BM, Kremen V, et al. Electrical stimulation modulates high γ activity and human memory performance. eNeuro. 2018;5(1).
Kucewicz MT, Berry BM, Miller LR, et al. Evidence for verbal memory enhancement with electrical brain stimulation in the lateral temporal cortex. Brain. 2018;141(4):971-978.
