In a recent Nature Neuroscience paper, scientists from Boston University postulated that a specific type of brain stimulation called Transcranial Alternating Current Stimulation (tACS) could enable a path toward achieving long-lasting memory enhancement. They proposed that brain rhythms can be neuro-moderated through repetitive tACS to improve cognitive functions (e.g., auditory–verbal memory) in older adults.

The team of scientists carried out research with two experimental groups, and a control group. Electrical pulse stimulation was conducted on specific brain regions of each group – the prefrontal cortex (associated with long-term memory) for the first group, and the inferior parietal lobe (associated with short-term memory) for the second group. The first group exhibited enhanced long-term memory in terms of recalling lists of words, the second group demonstrated better short-term memory, and the third group (that received no external stimulation) showed no improvement.

The researchers claimed that the brain performance of the experimental groups increased significantly, particularly in those with relatively poorer cognitive capacity. These improvements lasted for at least one month post-stimulation. Note that this enhanced memory was observed only when the stimulation was based on the natural rhythms of the specific brain regions – i.e., high-frequency stimulation for the prefrontal cortex, and low-frequency stimulation for the parietal lobe.

Electric pulses drive the communication between brain cells, and researchers increasingly believe that exposure to external electrical stimulation may strengthen such communication – thus improving attention, cognition, memory, and other brain functions. This particular research appears to be an important breakthrough because sustainable, long-term enhancements in working memory and long-term memory have not been generally observed in previous brain simulation experiments.