University of Pennsylvania researchers have found that electrical stimulation, given just when memory is expected to fail, can improve this function in the human brain. The same stimulation usually becomes disruptive when electrical pulses are delivered during periods of effective memory function.
The UPenn research team included Michael Kahana, professor of psychology, Youssef Ezzyat, a senior data scientist in Kahana's lab and Daniel Rizzuto, director of cognitive neuromodulation at the university. Their findings were published in the journal "Current Biology."
In a post on the University of Pennsylvania's official website, the study provides a significant step toward the long-term goal of Restoring Active Memory. It is a four-year Department of Defense project which focuses on developing next-generation technologies that aims to improve memory function in people who suffer from memory loss.
Ezzyat, who is the lead author of the paper, said that they applied machine-learning methods to electrical signals measured at widespread locations across the brain. They were able to identify neural activity that indicated when a patient will have lapses of memory encoding.
With the model, the team investigated how the effects of stimulation differ with poor and effective memory function. The study was conducted on neurosurgical patients who received treatment for epilepsy at various hospitals.
The patients were asked to study and recall lists of common words while they received safe levels of brain stimulation. The researchers recorded electrical activity from electrodes that were implanted in the brains of the patients as part of routine clinical care.
They found that memory worsens when electrical stimulation was delivered during periods of effective memory. On the other hand, when the brain was stimulated at times of poor function, the patients' memories significantly improved.
Kahana added that this was just like traffic patterns in the brain. When the brain was stimulated during a backup, it restores the normal flow of traffic.
More understanding of this process is expected to improve the lives of several patients especially those who had suffered traumatic brain injury or neurological diseases. It could also produce significant gains in memory performance.
