Low-current electrical pulses delivered to a specific brain area during learning improved recollection of distinct memories, according to a study published online in eLife.
Researchers at the University of California, Los Angeles (UCLA) believe electrical stimulation offers hope for the treatment of memory disorders, such as Alzheimer’s disease.
The study involved 13 patients with epilepsy who had ultrafine wires implanted in their brains to pinpoint the origin of seizures. During a person-recognition task, researchers monitored the wires to record neuronal activity as memories were formed, and then sent a specific pattern of quick pulses to the entorhinal area of the brain, an area critical to learning and memory.
In 8 of 9 patients who received electrical pulses to the right side of the entorhinal area, the ability to recognize specific faces and disregard similar-looking ones improved significantly. However, the 4 patients who received electrical stimulation on the left side of the brain area showed no improvement in recall.
By using the ultrafine wires, researchers were able to precisely target the stimulation while using a voltage that was one-tenth to one-fifth of the strength used in previous studies.
“These results suggest that microstimulation with physiologic level currents—a radical departure from commonly used deep brain stimulation protocols—is sufficient to modulate human behavior,” researchers wrote.
The findings also point to the importance of stimulating the right entorhinal region to promote improved memory recollection.
Titiz AS, Hill MRH, Mankin EA, et al. Theta-burst microstimulation in the human entorhinal area improves memory specificity. eLife. 2017 October 24.