1. Study examines relationship between traumatic brain injury and alcohol use

    November 27, 2017 by Ashley

    From the Elsevier press release:

    Head injury, which often damages brain regions overlapping with those involved in addictive behaviors, does not worsen drinking behavior in people with heavy alcohol use, according to a new study published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. The study, led by Dr. Andrew Mayer of the Mind Research Network and University of New Mexico in Albuquerque, New Mexico, also found that combining head injury with heavy alcohol use did not further alter the structure or function of the brain.

    “Individuals who consume too much alcohol are prone to experience more accidents as a result of their intoxication,” said Dr. Mayer. Importantly, he added, heavy alcohol use and traumatic brain injury (TBI) affect similar regions of the brain. This has led researchers to think that the common combination of head injury and heavy drinking may interact to worsen the brain damage already caused by chronic alcohol exposure.

    The study compared people with a recent history of heavy alcohol use and TBI with a control group carefully matched on lifetime history of alcohol exposure. Mayer and colleagues found the opposite of what they expected — heavy drinkers with a history of a TBI did not have worse drinking behavior, such as how often and how much they drank, compared with drinkers without a history of TBI.

    The researchers also used imaging techniques to measure the structure of the brain and its activity when the participants were given a taste of their favorite drink. “On average, the brains of the two groups were similar both in terms of the amount of lost tissue, as well as how each person’s brain responded to their favorite drink,” said Dr. Mayer, suggesting that TBI does not further damage brain circuitry in heavy drinkers.

    “The observation that the participants with TBI did not have greater neurocircuitry dysfunction than those without TBI might translate into greater therapeutic optimism for the treatment of individuals with a combination of TBI plus heavy drinking histories,” said Dr. Cameron Carter, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.


  2. Injury from contact sport has harmful, though temporary effect on memory

    November 22, 2017 by Ashley

    From the McMaster University press release:

    McMaster University neuroscientists studying sports-related head injuries have found that it takes less than a full concussion to cause memory loss, possibly because even mild trauma can interrupt the production of new neurons in a region of the brain responsible for memory.

    Though such losses are temporary, the findings raise questions about the long-term effects of repeated injuries and the academic performance of student athletes.

    The researchers spent months following dozens of athletes involved in high-contact sports such as rugby and football, and believe that concussions and repetitive impact can interrupt neurogenesis — or the creation of new neurons — in the hippocampus, a vulnerable region of the brain critical to memory.

    The findings were presented today (Tuesday, November 14th) at the Society for Neuroscience’s annual conference, Neuroscience 2017, in Washington D.C.

    “Not only are newborn neurons critical for memory, but they are also involved in mood and anxiety,” explains Melissa McCradden, a neuroscience postdoctoral fellow at McMaster University who conducted the work. “We believe these results may help explain why so many athletes experience difficulties with mood and anxiety in addition to memory problems.”

    For the study, researchers administered memory tests and assessed different types of athletes in two blocks over the course of two years. In the first block, they compared athletes who had suffered a concussion, uninjured athletes who played the same sport, same-sport athletes with musculoskeletal injuries, and healthy athletes who acted as a control group.

    Concussed athletes performed worse on the memory assessment called a mnemonic similarity test (MST), which evaluates a person’s ability to distinguish between images that are new, previously presented, or very similar to images previously presented.

    In the second study, rugby players were given the MST before the season started, halfway through the season, and one month after their last game. Scores for injured and uninjured athletes alike dropped midseason, compared to preseason scores, but recovered by the postseason assessment.

    Both concussed and non-concussed players showed a significant improvement in their performance on the test after a reprieve from their sport.

    For the concussed athletes, this occurred after being medically cleared to return to full practice and competition. For the rugby players, they improved after approximately a month away from the sport.

    If neurogenesis is negatively affected by concussion, researchers say, exercise could be an important tool in the recovery process, since it is known to promote the production of neurons. A growing body of new research suggests that gentle exercise which is introduced before a concussed patient is fully symptom free, is beneficial.

    “The important message here is that the brain does recover from injury after a period of reprieve,” says McCradden. “There is a tremendous potential for the brain to heal itself.”


  3. Study finds mapping brain connectivity with MRI may predict outcomes for cardiac arrest survivors

    November 3, 2017 by Ashley

    From the Johns Hopkins Medicine press release:

    A new study led by Johns Hopkins researchers found that measures of connectivity within specific cerebral networks were strongly linked to long-term functional outcomes in patients who had suffered severe brain injury following a cardiac arrest.

    A description of the findings, published in October in the journal Radiology, suggests that mapping and measuring such connectivity may result in highly accurate and reliable markers of long-term recovery trajectories in people with neurological damage caused by heart attacks, strokes, brain hemorrhage or trauma.

    “By analyzing functional MRI data we are able to see where brain network disruption is occurring, and determine how these changes relate to the likelihood of recovery from brain damage,” says Robert Stevens, M.D., associate professor of anesthesiology and critical care medicine at the Johns Hopkins University School of Medicine, and the paper’s senior author.

    Cardiac arrest, or the sudden loss of heart function, affects an estimated 535,000 people in the United States each year, according to the American Heart Association. The loss of blood flow, and its restoration through resuscitation, is associated with rapid and widespread damage to the brain, leading to disabling neurological and cognitive problems in survivors.

    Several modifiable factors, such as timeliness and quality of cardiac resuscitation and the strict control of body temperature to avoid fever, strongly influence the magnitude of brain damage and the prospects for recovery, says Stevens.

    He adds that current methods to predict how an individual will recover over time are limited, but advanced imaging techniques such as quantitative brain mapping using MRI data could transform practice by allowing clinicians to make better-informed decisions about care. MRI can specifically and accurately identify changes in tissue structure, blood flow and functional activation. Functional connectivity is determined by analyzing the temporal correlation of functional activation in different parts of the brain, thereby establishing the strength of connections between anatomically distinct regions. Clusters of brain regions that are highly correlated are called networks, and the degree of correlation can be measured within and between networks.

    For their study, the Hopkins researchers and their colleagues assessed the brain’s functional activation in 46 patients who were in a coma after cardiac arrest between July 2007 and October 2013. MRI was performed on all patients on average 12.6 days after cardiac arrest, and the analysis focused on four networks in the brain: dorsal attention network (DAN, which is active when a person uses energy to focus attention); default mode network (DMN, which is active when an individual is at rest); executive control network (ECN, which is active while initiating tasks and is associated with reward and inhibition); and salience network (SN, a network that determines the importance of stimuli and may direct activation of other cognitive networks). Of the participants, 32 were men, and the average age was 49.

    One year after the patients’ cardiac arrests, the researchers assessed survivors with the Cerebral Performance Category (CPC) Scale, a commonly used measure of neurological function following cardiac arrest. The test uses a scale from 1 to 5, with 1 indicating minimal to no disability and 5 indicating brain death. Eleven of the 46 patients who had favorable outcomes (a score of 1 or 2) showed higher connectivity within the DMN network, as well as greater anti-correlation (when one is active the other is not) between the SN and ECN and the SN and DMN, when compared with patients who had an unfavorable outcome (CPC greater than 2). Remarkably, the functional connectivity markers predicted outcomes more accurately when compared with structural measures of, for example, tissue damage, used in conventional MRI scans.

    “These findings highlight a potential realm of precision medicine using brain network biomarkers that are discriminative and predictive of outcomes,” says Haris Sair, M.D., interim director of neuroradiology at the Johns Hopkins University School of Medicine and the study’s lead author. “In the future, connectivity biomarkers may help guide new therapies for targeted treatment to improve brain function.”