New research has discovered that well-timed pulses from electrodes implanted in the brain can enhance memory in some people. This is potentially a huge breakthrough in the treatment of dementia, head injuries and other memory-related maladies. Previous attempts to stimulate human memory with implanted electrodes had produced mixed results: some experiments seemed to sharpen memory, but others muddled it. This new study shows that it is the timing of the stimulation which is crucial to its success. Stimulating memory areas when they are functioning poorly improves the brain’s encoding of new information. However, doing it to areas of the brain that are already operating well impairs their effectiveness.

“We all have times when we’re foggy, and others when we’re sharp,” said Michael Kahana, who led the research team. “We found that jostling the system when it’s in a low functioning state can jump it to a high functioning state.” This study was focused on epilepsy patients, so further research is needed to determine whether the procedure will work on people with other conditions. But in establishing the importance of timing, the field seems to have turned a corner. “The cool thing about this research is that it shows why stimulation works in some conditions, and why it doesn’t work in others,” said Bradley Voytek, professor of neuroscience at the University of California (US). “It gives us a blueprint for moving forward.”