The corpus callosum is a bundle of nerve fibers that is responsible for carrying signals between the left and right hemispheres of the brain. Research conducted on this area of the brain has revealed that it is particularly vulnerable to damage from concussion.
However, how this type of damage impacts cognitive function is still being further investigated. That is why researchers at New York University (NYU) School of Medicine in New York City conducted new research that compares the corpus callosum in 36 patients with recent concussions to that of 27 healthy controls. The participants underwent an innovative brain MRI technique that uses measures of water diffusion to provide a microscopic view of the brain's signal-carrying white matter.
Melanie Wegener, M.D., one of the co-authors of the study, said, “Looking at how water molecules are diffusing in the nerve fibers in the corpus callosum and within the microenvironment around the nerve fibers allows us to better understand the white matter microstructural injury that occurs.”
The second innovative advance researchers came up with is called an Interhemispheric Speed of Processing Task. This test gauges how well the two hemispheres in the brain communicate back and forth. Participants in the study are asked it in a chair and focus their eyes on the letter X that can be seen on a screen in front of them. Three-letter words are then flashed to the right or the left of the X. The participants have to say the word they see as fast as they can. Researchers uncovered an interesting phenomenon when they tested the reaction time in both patients with concussion and healthy controls.
According to Dr. Wegener, “There is a definite and reproducible delay in reaction time to the words presented to the left of the X compared with words presented to the right visual field. This shows it takes time for information to cross the corpus callosum from one hemisphere to the other, which is measured by the difference in response time between words presented to different sides of our visual field.”
Researchers say the delay is most likely attributed to the fact that the left hemisphere of the brain is where language function is found. This means the information in the left visual field is first transmitted to the right visual cortex in the brain and then sent over the corpus callosum to reach the left language center. On the other hand, words that appear in the right visual field do not need to cross the corpus callosum.
The participants’ performance on the test was in line with findings on the brain MRI. The healthy controls’ reaction time corresponded with several diffusion measures in the splenium, which is an area of the corpus callosum found between the right visual cortex and the left language center. A similar correlation couldn’t be found in patients who suffered concussions. According to researchers, this is indicative of microstructural changes relating to the injury.
Talking about the significance of the findings, Dr. Wegener said, “We saw a correlation between white matter microstructure injury and the clinical status of the patient. This information could ultimately help with treatment in patients who have mild traumatic brain injury."Are you or someone you know dealing with a traumatic brain injury caused by an accident? If so, call Scarlett Law Group today at (415) 688-2176 to set up your consultation with our dedicated legal team.