Wednesday, July 13th, 2011
Transcranial magnetic stimulation (TMS) is able to minimize forgetfulness by disrupting targeted brain regions as they compete between memories, according to a new study at Beth Israel Deaconess Medical Center.
“For the last 100 years, it has been appreciated that trying to learn facts and skills in quick succession can be a frustrating exercise,” explains Edwin Robertson, MD, DPhil, an Associate Professor of Neurology at Harvard Medical School. “Because no sooner has a new memory been acquired than its retention is jeopardized by learning another fact or skill.”
Robertson, along with neurologist and co-author Daniel Cohen, MD, observed 120 college-age students who participated in two memory tests.
The first was a finger-tapping motor skills task, and the second was a memory test in which volunteers had to remember a series of words. Half of the participants performed the tasks in this order, while the other half learned these same two tasks in reverse order.
“The study subjects performed these back-to-back exercises in the morning,” he explains. “They then returned 12 hours later and re-performed the tests. As predicted, their recall for either the word list or the motor-skill task had decreased when they were re-tested.”
Just after the initial testing, the researchers administered TMS which is a noninvasive procedure that uses a magnetic simulator that can create a current in the brain through a magnetic field.
“Because brain cells communicate through a process of chemical and electrical signals, applying a mild electrical current to the brain can influence the signals,” Robertson explains.
The researchers focused on two specific brain areas: the dorsolateral prefrontal cortex and the primary motor cortex. They found that when they applied TMS to these specific regions, they could diminish the interference and competition between the motor skill and word tasks and both memories remained intact.
“This elegant study provides fundamental new insights into the way our brain copes with the challenge of learning multiple skills and making multiple memories,” says Alvaro Pascual-Leone, MD, PhD, Director of the Berenson-Allen Center for Noninvasive Brain Stimulation.
“Specific brain structures seem to carefully balance how much we retain and how much we forget. Learning and remembering is a dynamic process and our brain devotes resources to keep the process flexible. By better understanding this process, we may be able to find novel approaches to help enhance learning and treat patients with memory problems and learning disabilities.”
“Our observations suggest that distinct mechanisms support the communication between different types of memory processing,” adds Robertson.
“This provides a more dynamic and flexible account of memory organization than was previously believed. We’ve demonstrated that the interference between memories is actively mediated by brain areas and so may serve an important function that has previously been overlooked.”
The findings are described in the June 26 Advance Online issue of Nature Neuroscience.
Thursday, July 7th, 2011
Every year, 1.7 million Americans sustain a traumatic brain injury, nearly one in five as the result of a war injury.
While medicine can help keep many of the most severe cases alive after a coma, giving them back function is something science has been unable to do.
However, now a promising study that utilizes electromagnetic stimulation could help those cases wake up.
Life for Josh Villa changed in an instant as the result of a car accident six years ago. The once active father of three was left in a coma-like state with his mother providing him with constant care.
“Everybody says, ‘How can you do it?’,” said Laurie McAndrews. “You just do what you need to do when is put before you.”
The year after the accident, McAndrews enrolled her son into a first-of-its-kind study that used magnetic therapy known as transcranial magnetic stimulation.
The therapy, brain child of doctor Theresa Pape, uses a coil creates a magnetic field that stimulates the brain.
“If we can get these neurons up here to activate and eventually descend down here to the brain stem and then ascend back up to the cortex, we should be able to facilitate the repair of the brain,” said Pape, clinical neuroscientist at the United States Department of Veteran Affairs.
With more than 300,000 sustaining a brain injury in Iraq and Afghanistan, 2,500 severe like Villa’s, the work is especially important for injured troops.
Although two-thirds of those sustaining brain injuries regain full consciousness, there are no treatments available to get them beyond that. Results of the study are promising and after 15 sessions, Villa went from not responding at all to holding his head up and occasionally following commands.
Pape has observed Villa even speaking a few words like “Mom”, “Help me” and “Pain.”
“Our mouths kind of hung open,” said Pape. “We thought, ‘Whoa,’ and we said, ‘Let’s see if we can repeat this.’”
Further magnetic stimulation therapy did not help Villa, but Pape treated a second patient that showed even better results.
“He was fully conscious,” said Pape. “He started talking to us, basically, and his sister and his brother and answering commands consistently, answering yes/no questions and initiating conversation.”
“I guess I hoped for that,” said McAndrews. “It didn’t happen, but a new study is always hope.”
About four more people will be studied over the next three years. The next patient is set to be a veteran.
Once the safety trial is over, Pape and her team will run a randomized clinical trial using both newly-injured patients and those living with older severe traumatic brain injuries.
Villa, who is in a minimally-conscious state, could be a candidate for that trial.