Stress-response mediated by repeated media exposure to collective traumatic events

In the modern world, information about traumatic events, such as earthquakes, major accidents, and terrorist strikes claiming innocent lives, spreads quickly. Further, media provides repeated exposure to the major catastrophic events in the form of newsfeeds that add new details about the events as they are uncovered. It is an inherently important question whether media exposure can induce stress responses in a similar manner and magnitude than being at the site of the catastrophe. This is an important question from at least three perspectives: 1) answering this question provides important information about human cognition and emotional responses in the modern global information flow environment, 2) mental health professionals can better appreciate media-exposure related problems, and 3) also given that the population at large is often the intended psychological target of terrorists who carry out acts of violence.

In their recent study, Holman et al. (2013) compared media vs. direct exposure to a collective trauma, by carrying out a survey over the two weeks following the Boston marathon bombings, in representative samples of persons living in Boston, New York, and rest of the united states. When the authors adjusted acute stress symptom scores for demographics, preceding mental health, and prior collective stress exposure, it was observed that >6 hours of media exposure to the marathon bombing events during the week following the bombings was associated with higher acute stress symptoms than direct exposure to the bombings.

These very interesting findings suggest that indirect exposure to traumatic events via repeated media coverage may produce even stronger stress responses than direct exposure to the event, which is a clear indication of the robustness of prolonged and repeated media-exposure in triggering stress-related mental health problems, even though, as pointed out by the authors, it has to be kept in mind that emergency actions taken by the local authorities in cases of direct exposure to the bombings likely lessened distress in that group. Mass media may thus inadvertently serve as a channel that spreads the psychological trauma far beyond the directly affected population. Outside of the scope of considering the effects of mass-media coverage, these results further suggest that being repeatedly related information about a catastrophic event can trigger stress response and produce symptoms of post-traumatic stress disorder without direct exposure, which may also be an important form of societal-cultural learning.

Reference: Holman EA, Garfin DR, Silver RC. Media’s role in broadcasting acute stress following the Boston Marathon bombings. Proc Natl Acad Sci USA (2013) e-publication ahead of print. http://dx.doi.org/10.1073/pnas.1316265110

Increased functional brain network modularity predicts working memory deficits in early-stage multiple sclerosis

Multiple sclerosis is a neurological disorder where, due to inflammatory processes, there is focal demyelination and axonal damage that step-by-step severs the anatomical connections of the brain. Recent neuroimaging studies and theoretical work are both pointing out the importance of inter-area connectivity and interactions in giving rise to perceptual and cognitive functions. Therefore, one of the crucial questions regarding multiple sclerosis is in which ways the breaking down of brain connectivity alters the way that the functional networks are reorganized and how this impacts cognition.

In their recent study, Gamboa et al. (2013) recorded resting state functional magnetic resonance imaging in early-stage multiple sclerosis patients and healthy controls. As a measure of cognition, subjects of both groups separately performed the Paced auditory serial addition task in a dual task manner to assess working memory, attention, and speed of information processing. Using graph theoretical analysis of brain functional connectivity, the authors observed increased modularity in the early-stage multiple sclerosis patients as compared with the healthy controls. Furthermore, the increased modularity of brain functional connectivity negatively correlated with performance in the neuropsychological test of working memory, attention, and speed of information processing.

These highly interesting findings demonstrate how the subtle changes in connectivity due to focal damage caused to axonal fibers in the earliest stages of multiple sclerosis alter the functional network properties of the brain, and how such changes in brain network activity adversely reflects upon cognitive ability. It is easy to see how these findings pave way for further studies examining how accumulating focal damage to the links of the functional networks affect perceptual and cognitive functions in multiple sclerosis patients. Given that relatively robust effects were seen in these early-stage patients, these findings could also be interesting from the point of view of clinical research aiming at development of measures that enable follow-up of disease progression.

Reference: Gamboa OL, Tagliazucchi E, vonWegner F, Jurcoane A, Wahl M, Laufs H, Ziemann U. Working memory performance of early MS patients correlates inversely with modularity increases in resting state functional connectivity networks. NeuroImage (2013) e-publication ahead of print. http://dx.doi.org/10.1016/j.neuroimage.2013.12.008