One gene influences recovery from traumatic brain injury

February 26, 2014

Researchers report that one change in the sequence of the BDNF gene causes some people to be more impaired by traumatic brain injury (TBI) than others with comparable wounds.

The study, described in the journal PLOS ONE, measured general in a group of 156 Vietnam War veterans who suffered penetrating head wounds during the war. All of the study subjects had damage to the prefrontal cortex, a brain region behind the forehead that is important to cognitive tasks such as planning, problem-solving, self-restraint and complex thought.

The researchers controlled for the size and location of subjects' brain injuries and other factors, such as intelligence prior to injury, which might have contributed to differences in cognitive function. (Prior to combat, the veterans had completed the Armed Forces Qualifications Test, which included measures of intelligence that provided a baseline for the new analysis.)

"We administered a large, cognitive battery of tests to investigate how they performed after their injury," said study leader Aron Barbey, a professor of speech and hearing science, of psychology and of neuroscience at the University of Illinois. "And we had a team of neurologists who helped characterize the nature and scope of the patients' brain injuries."

The researchers also collected blood for a genetic analysis, focusing on a gene known as BDNF (brain-derived neurotrophic factor).

The team found that a single polymorphism (a difference in one "letter" of the sequence) in the BDNF gene accounted for significant differences in intelligence among those with similar injuries and comparable intelligence before being injured.

"BDNF is a basic growth factor and it's related to neurogenesis, the production of new neurons," Barbey said. "What we found is that if people have a specific polymorphism in the BDNF gene, they recovered to a greater extent than those with a different variant of the gene."

The change in the gene alters the BDNF protein: The amino acid methionine (Met) is incorporated at a specific site in the protein instead of valine (Val). Since people inherit two versions of each gene, one from each parent, they have either Val/Val, Val/Met or Met/Met variants of the gene.

"The effects of this difference were large – very large," Barbey said. "If an individual had the Val/Val combination, then their performance on a battery of cognitive tests (conducted long after the injury occurred) was remarkably lower than that of individuals who had the Val/Met or Met/Met combination."

On average, those with the Val/Val polymorphism scored about eight IQ points lower on tests of general intelligence than those with the Val/Met or Met/Met variants, Barbey said. Those with the Val/Val variant also were significantly more impaired in "specific competencies for intelligence like verbal comprehension, perceptual organization, working memory and processing speed," he said.

To test these results, the researchers did the analysis over again "in a subset of individuals who had very similar (brain injuries) to the other group," Barbey said. "We found the same kind of effects, suggesting that lesion location isn't a factor influencing the difference between the groups."

The finding opens a new avenue of exploration for treatments to aid the process of recovery from TBI, Barbey said.

Explore further: Is multitasking mastery in the genes?

Related Stories

Is multitasking mastery in the genes?

January 7, 2014

Human factors/ergonomics researchers have long studied the connection between cognitive function and the ability to perform well on multiple simultaneous tasks, and recently a group of neuroergonomics researchers went a step ...

Researchers map emotional intelligence in the brain

January 22, 2013

A new study of 152 Vietnam veterans with combat-related brain injuries offers the first detailed map of the brain regions that contribute to emotional intelligence – the ability to process emotional information and navigate ...

Researchers map brain areas vital to understanding language

November 21, 2013

When reading text or listening to someone speak, we construct rich mental models that allow us to draw conclusions about other people, objects, actions, events, mental states and contexts. This ability to understand written ...

Recommended for you

Neuro chip records brain cell activity

October 26, 2016

Brain functions are controlled by millions of brain cells. However, in order to understand how the brain controls functions, such as simple reflexes or learning and memory, we must be able to record the activity of large ...

Can a brain-computer interface convert your thoughts to text?

October 25, 2016

Ever wonder what it would be like if a device could decode your thoughts into actual speech or written words? While this might enhance the capabilities of already existing speech interfaces with devices, it could be a potential ...

The current state of psychobiotics

October 25, 2016

Now that we know that gut bacteria can speak to the brain—in ways that affect our mood, our appetite, and even our circadian rhythms—the next challenge for scientists is to control this communication. The science of psychobiotics, ...

After blindness, the adult brain can learn to see again

October 25, 2016

More than 40 million people worldwide are blind, and many of them reach this condition after many years of slow and progressive retinal degeneration. The development of sophisticated prostheses or new light-responsive elements, ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.