With the possible exception of those affected by hyperthylmesia - a rare condition where a person has an extraordinary capability to recall events from their past - most of us wouldn't mind having our memory enhanced. That's just what appears to have happened to a group of mice when targeted areas of their brains were electrically stimulated. The treatment triggered an increase in the creation of new cells in the hippocampus, with experiment results suggesting the mice's spatial learning improved. The researchers responsible say the results could have implications for the treatment of memory disorders in humans.
A clinical treatment known as deep brain stimulation (DBS), which delivers electrical pulses to targeted areas of the brain, has been used with some success in the treatment of movement and affective disorders, such as Parkinson's disease, and has also been recently explored for treatment of a range of neurologic and psychiatric conditions, including major depression and Tourette syndrome. The findings of this new study led by Paul Frankland, PhD, of The Hospital for Sick Children (SickKids), suggests the treatment could also have applications for memory disorders.
Throughout our lives, new cells are born in parts of the hippocampus - an area of the brain that plays important roles in spatial navigation and the consolidation of information from short-term to long-term memory. It is one of the first regions of the brain to suffer damage in Alzheimer's disease, with memory problems and disorientation among the first symptoms.
Frankland and his colleagues found that subjecting the entorhinal cortex - a region of the brain that directly communicates with the hippocampus - of adult mice to one hour of electrical stimulation led to a two-fold increase in new cells in the hippocampus. Although the burst of new cells lasted for only about one week, the cells produced during this time developed normally and made connections with nearby brain cells.
To test whether the newly integrated cells produced changes in memory, six weeks later the researchers tested how well the mice learned to navigate onto a landing submerged in a small pool of water. Compared with mice that didn't receive the therapy, the DBS-treated mice spent more time swimming near the landing, which the researchers say suggests improved spatial learning.
The results of the study echo a previous study that saw patients receive a boost in math skills lasting up to six months after an electrical current was applied to their parietal lobe - a region of the brain crucial for numerical understanding.
The findings of this new DBS study are published in the September 21 issue of The Journal of Neuroscience.