Scientists have found the precise brain areas that can be electrically stimulated to enhance people's recollection of distinct memories, an advance that may help people with epilepsy improve their ability to recognise faces.
The study, by researchers from the University of California, Los Angeles in the US, builds on previous research which demonstrated that human memory can be strengthened by electrically stimulating the brain's entorhinal cortex.
The ability to recognise faces of specific people improved in eight of nine epilepsy patients after they received 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.
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, published in the New England Journal of Medicine, 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.