Individuals with epilepsy who received electrical microstimulation pulses showed a significant improvement in their ability to recognize specific faces and ignore similar ones, new UCLA research reports.
Eight of nine patients’ ability to recognize the faces of specific people improved after receiving low-current electrical pulses to the right side of the brain’s entorhinal area, which is critical to learning and memory. However, electrical stimulation delivered to the left side of the region, tested on four other people, resulted in no improvement in the patient’s recall.
The study builds on 2012 UCLA research demonstrating that human memory can be strengthened by electrically stimulating the brain’s entorhinal cortex.
Ultrafine Wire Implants
Researchers followed 13 people with epilepsy who had ultrafine wires implanted in their brains to pinpoint the origin of their seizures. The team monitored the wires to record neuron activity as memories were formed, then sent a specific pattern of quick pulses back into the entorhinal area.
Using the ultrafine wires allowed researchers to precisely target the stimulation but use a voltage as low as one-tenth to one-fifth as strong as had been used in previous studies.
The study suggests that even low currents of electricity can affect the brain circuits that control memory and human learning. It also illustrates the importance of precisely targeting the stimulation to the right entorhinal region. Other studies that applied stimulation over a wide swath of brain tissue have produce conflicting results.
Electrical stimulation could offer promise for treating memory disorders like Alzheimer’s disease.
The study was funded by the National Institute of Neurological Disorders and Stroke, the A.P. Giannini Foundation, the Defense Advanced Research Projects Agency, the G. Harold and Leila Y. Mathers Charitable Foundation and the Swiss National Science Foundation.
Ali S Titiz, Michael R H Hill, Emily A Mankin, Zahra M Aghajan, Dawn Eliashiv , Natalia Tchemodano, Uri Maoz, John Stern, Michelle E Tran, Peter Schuette, Eric Behnke, Nanthia A Suthana, Itzhak Fried
Theta-burst microstimulation in the human entorhinal area improves memory specificity
eLife 2017;6:e29515