This gene codes for a protein called Brain-Derived Neurotrophic Factor, which strengthens memory by facilitating communication amongst brain cells. In people who carry this variant, the protein is not produced in sufficient amounts, hindering learning and memory.
Dr. Steven Cramer, associate professor in the Department of Neurology, authored this study along with graduate student Stephanie McHughen. Their research involved finding various ways to heal the brain after suffering conditions such as a stroke.
The BDNF protein is important to the healing process because it is the most abundant growth factor in the brain. People with this gene variant do not recover well after a stroke.
A driving test study was conducted to compare the motor behavior in people with and without the variant.
The driving test was administered with the help of the Engineering Department. A focus group of 29 people, with seven amongst the group carrying the variant gene, were asked to drive on a simulator pre-programmed to have difficult turns and slippery roads. The subjects were asked to drive with a line in the center.
Their performance was recorded by a computer installed in the steering wheel, which measured how much the subject deviated from the black line. The test was repeated four days later.
According to the results, people with the variant gene performed worse compared to people with the normal BDNF gene. The participants with the variant remembered less the second time they were ask to drive on the same track.
“There were people with the variant who did well and some people without it who did not perform so well,” McHughen said.
No conclusions regarding this gene being the direct cause of bad driving can be drawn at the moment. However, the driving test did show that people with the variant performed poorly in learning and retaining environment.
The gene variant does not always have a negative effect.
“It exists in a third of the population. It can’t be totally bad, since it hasn’t been eliminated by evolutionary forces,” McHughen said.
In fact, the gene variant is said to be helpful in people with diseases such as Parkinson’s, Huntington’s and Multiple Sclerosis.
“The lack of communication in the brain leads to stability and plasticity which is helpful in patients with such diseases because their cognitive function deteriorates more slowly,” McHughen said.
Therefore, a Huntington’s patient with this variant will have more time to fight the disease than a person with the normal BDNF gene.
Further study of the BDNF gene may lead to improved methods of rehabilitation after stroke as patients with this variant may require special techniques.
In the future, Dr. Cramer hopes to give a similar test specifically to stroke patients.
“Next time the two tests will be over a longer period of time because the change in learning and memory generally happens over two weeks,” Cramer said.
Cramer is also involved in an ongoing NIH funded study called Stroke Robot. This study gives eligible stroke patients a Hand and Wrist Assisting Robotic Device (HWARD) for free.
“It helps you gain a better arm after a stroke,” Cramer said.
This robot senses when the patient is trying to move his/her hand and facilitates movement. When these patients come for therapy, their brain function is monitored further for changes and improvement.
The results of the driving test neither prove nor disprove any racial, gender-based or age-based stereotypes regarding bad driving.
As Dr. Cramer said, “It is simply not what we were looking for.”
Having the variant BDNF gene does not guarantee bad driving.
“It is always situation specific,” McHughen said.
Hopefully, this study will lead to more discoveries that help patients with brain injuries return to their normal lives sooner.