Precise memory, for example, is used to recall specific colors, shapes and locations of buildings, versus just knowing the name of the town that the building is located in. Scientists were able to improve the precision of patients’ memory for identifying locations by stimulating the area of the brain that holds spatial memory.
“We show that it is possible to target the portion of the brain responsible for this type of memory and to improve it,” said Joel Voss, lead author on the study and assistant professor of medical social sciences at Northwestern University. “People with brain injuries have problems with precise memory as do individuals with dementia, and so our findings could be useful in developing new treatments for these conditions.”
Approximately 47.5 million people have dementia worldwide, with an average of 7.7 million new cases each year, according to the World Health Organization. Dementia is usually caused by Alzheimers disease and is characterized by deterioration in memory, thinking, behavior and the ability to perform everyday activities.
Memories are usually stored in the brain and “remembered” through a series of synapses that pass from neuron to neuron. If the strength of these synapses is weak, the brain starts to lose the ability to remember.
Using an MRI, scientists were able to determine where memory-related brain networks were located and stimulated them with non-invasive electromagnetic stimulation. The brain stimulation lasted 24 hours and correlated with brain activity changes.
“We improved people’s memory in a very specific and important way a full day after we stimulated their brains,” said Voss.
Scientists used detailed memory tests to prove that spatial precision memory was improved and an EEG reading showed that brain network function was improved.
Brain stimulation has gotten a bit of a bad rap because of the enthusiasm of amateurs. There was actually a do-it-yourself version of brain stimulation circulating late last year. The neurostimulation included self-administered electrical shocks to the brain for less than $10 using a 9V battery. The shocks lasted for 10 to 20 minutes and people used it just like coffee. Scientists warned about the use of DIY stimulation because it could have a negative effect on neuron transmission.
“It is questionable whether the stimulation (electricity) actually ‘makes it in’ to your brain at all,” Voss said. “If people are working out ways to give themselves high intensities that might actually get into the brain, then they could be doing harm (because they are not necessarily controlling exactly where it will go in their brains, and some areas should not be stimulated), and they are doing it with no medical supervision, in case there is an accident or complication.”
In contrast, Voss and his colleagues use a powerful electromagnetic stimulator that costs around $200,000 to fabricates. It allows them to induce relatively strong electrical pulses in specific brain regions, with targeting based on an individual’s MRI scans, according to Voss.
“For a good comparison, when we aim our stimulator at the part of the brain that controls muscles, we can make specific parts of the body move by stimulating the brain,” Voss said. “In contrast, when you put a DYI battery-based brain stimulator over the same area, absolutely nothing happens whatsoever. Instead of aiming at brain areas that control muscles, we aim at brain areas that control memory, trying to influence them in specific ways. We also perform our studies in a hospital setting with supervision by a neurologist.”
This non-invasive stimulation gives scientists a better understanding of memory improvement. Previous brain stimulation only lasted a short amount of time and have short-lived effects on thinking abilities.
In addition to Voss, the research was performed by Aneesha S. Nilakantan, Donna J. Bridge, Elise P. Gagnon and Stephen A. VanHaerents and was funded by grants from the National Institutes of Health. The report was published online in the Current Biology journal.
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