Concussion alters how information is transmitted within the brain
December 3, 2019
Science Daily/Radiological Society of North America
Damage from concussion alters the way information is transmitted between the two halves of the brain, according to a new study presented today at the annual meeting of the Radiological Society of North America (RSNA).
Research has shown that the corpus callosum, a bundle of nerve fibers that carries signals between the brain's left and right hemispheres, is vulnerable to damage from mild traumatic brain injury, commonly known as concussion. Less is known about the impact of this damage on cognitive function.
To learn more, researchers at New York University (NYU) School of Medicine in New York City compared the condition of the corpus callosum in 36 patients with recent concussion to that of 27 healthy controls. They studied the participants' brains with two innovative advances, including an MRI technique that uses measures of water diffusion to provide a microscopic view of the brain's signal-carrying white matter.
"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," said study co-author Melanie Wegener, M.D., resident physician at NYU Langone Health in New York City.
Dr. Wegener and colleagues combined the MRI findings with results from the study's second innovative advance, called an Interhemispheric Speed of Processing Task, a test developed at NYU Langone that evaluates how well the two hemispheres in the brain communicate with each other.
For the test, the participants were told to sit in a chair and focus their gaze on the letter X that was displayed on a screen directly in front of them. The researchers then flashed three-letter words to the right or the left of the X and asked the participants to say those words as quickly as possible. When the researchers evaluated this reaction time in both patients with concussion and healthy controls, they noticed an interesting phenomenon.
"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," Dr. Wegener said. "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."
This delay is likely due to the fact that language function is most often located in the brain's left hemisphere. This means that information presented to the left visual field is first transmitted to the right visual cortex in the brain and then has to cross over the corpus callosum to get to the left language center. In contrast, words that are presented to the right visual field do not need to cross the corpus callosum.
Performance on the test correlated with brain findings on MRI. In the healthy controls, reaction time corresponded with several diffusion measures in the splenium, an area of the corpus callosum located between the right visual cortex and the left language center. No such correlation was found in the concussion patients, suggesting microstructural changes relating to injury.
"We saw a correlation between white matter microstructure injury and the clinical status of the patient," Dr. Wegener said. "This information could ultimately help with treatment in patients who have mild traumatic brain injury."
For instance, Dr. Wegener said, patients could undergo MRI immediately after a concussion to see if they experienced any clinically important white matter injury and thus may benefit from early intervention.
"Another thing we can do is use MRI to look at patients' brains during treatment and monitor the microstructure to see if there is a treatment-related response," she said.
https://www.sciencedaily.com/releases/2019/12/191203082910.htm
How playing the drums changes the brain
Many years of playing the instrument leave clear traces
December 9, 2019
Science Daily/Ruhr-University Bochum
People who play drums regularly for years differ from unmusical people in their brain structure and function. The results of a study by researchers from Bochum suggest that they have fewer, but thicker fibres in the main connecting tract between the two halves of the brain. In addition, their motor brain areas are organised more efficiently. This is the conclusion drawn by a research team headed by Dr. Lara Schlaffke from the Bergmannsheil university clinic in Bochum and Associate Professor Dr. Sebastian Ocklenburg from the biopsychology research unit at Ruhr-Universität Bochum following a study with magnetic resonance imaging (MRI). The results have been published in the journal Brain and Behavior, online on 4 December 2019.
Drummers were never previously studied
"It has long been understood that playing a musical instrument can change the brain via neuroplastic processes," says Sarah Friedrich, who wrote her bachelor's thesis on this project. "But no one had previously looked specifically into drummers," she adds.
The researchers from Bochum were interested in this group because their motor coordination far surpasses that of untrained people. "Most people can only perform fine motor tasks with one hand and have problems playing different rhythms with both hands at the same time," explains Lara Schlaffke. "Drummers can do things that are impossible for untrained people."
Drumming first, then brain scans
The team intended to gain new insights into the organisation of complex motor processes in the brain by identifying the changes in the brain caused by this training. The researchers tested 20 professional drummers who have played their instrument for an average of 17 years and currently practice for more than ten hours per week. They examined them using various MRI imaging techniques that provide insights into the structure and function of the brain. They then compared the data with measurements of 24 unmusical control subjects. In the first step, both groups had to play drums to test their abilities and were then examined in the MRI scanner.
More efficient motor processing
Drummers presented clear differences in the front part of the corpus callosum, a brain structure that connects the two hemispheres and whose front part is responsible for motor planning. The data indicated that the drummers had fewer but thicker fibres in this important connecting tract between the brain hemispheres. This allows musicians to exchange information between the hemispheres more quickly than the controls. The structure of the corpus callosum also predicted the performance in the drum test: the higher the measure of the thickness of the fibres in the corpus callosum, the better the drumming performance.
Moreover, the brain of drummers was less active in motor tasks than that of control subjects. This phenomenon is referred to as sparse sampling: a more efficient brain organisation in the areas leads to less activation in professionals.
Older participants wanted for new study
"We would like to thank our highly motivated participants who took part in the study," says Lara Schlaffke. "It was great fun working with you."
https://www.sciencedaily.com/releases/2019/12/191209110513.htm
Train your brain, change your brain
April 14, 2019
Science Daily/D'Or Institute for Research and Education
Less than one hour of brain training with neurofeedback leads to a strengthening of neural connections and communication among brain areas. This is the main finding of a new study conducted at D'Or Institute for Research and Education (IDOR), published today in Neuroimage. According to the authors, the study may pave the way for the optimization and development of therapeutic approaches against stroke and Parkinson's, for example.
"We knew that the brain has an amazing ability to adapt itself, but we were not sure that we could observe these changes so quickly. Understanding of how we can impact on brain wiring and functioning is the key to treat neurological disorders," says Theo Marins, a biomedical scientist from IDOR and the Ph.D. responsible for the study.
Neurofeedback has been considered a promising way to regulate dysfunctional brain areas associated with disorders, such as chronic pain and depression, for example. With this technique, the magnetic resonance equipment helps individuals to have access to their own brain activity in real time and quickly gain control over it.
Thirty-six healthy subjects participated in the study in which the goal was to increase the activity of brain regions involved in hand movements. However, instead of actually move their hand, participants were asked to only imagine the movement, in total rest. Nineteen of them received the real brain training and the remaining seventeen were trained with placebo neurofeedback, for comparisons purposes. Immediately before and after the brain training, which lasted around 30 minutes, their neural networks were scanned in order to investigate the impact of the neurofeedback (or placebo) on brain wiring and communication, also known as structural and functional connectivity, respectively.
The results show that the corpus callosum -- the major cerebral bridge that connects the right and left hemispheres -- exhibited increased integrity, and the neural network controlling the movements of the body became strengthened. It seems that the whole system became more robust. Likewise, the training also had a positive impact on the default mode network, a brain network which is impaired after stroke, Parkinson's and depression, for example. These changes were not observed in the control group.
"We showed that the neurofeedback can be considered a powerful tool to induce brain changes at record speed. Now, our goal is to develop new studies to test whether patients with neurological disorders can also benefit from it," concludes Fernanda Tovar Moll, president of IDOR and leader of the study.
https://www.sciencedaily.com/releases/2019/04/190414111449.htm