Although it has been known that electrical stimulation to the brain can improve memory, neuroscientists at David Geffen School of Medicine at UCLA have pinpointed exactly where to direct the electric impulse as well as discovered that a weaker signal will do the trick.
The 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.
Eight of nine patients’ ability to recognize the faces of specific people improved after receiving 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.
Noting that other studies have resulted in less consistent results, the authors show that it is both where and how the charge is applied, and express the capacity this treatment has for tackling memory disorders like Alzheimer’s disease.
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.