While participation in youth sports bolster a myriad of health benefits, it can also pose a risk to the athlete's health from the increasing prevalence of repetitive mild traumatic brain injuries (TBI), often referred to as concussions. The adverse effects from repeated traumatic blows give a combination of acute symptoms, which may potentially develop into long-term complications. There is little known about the epidemiology of concussions, and thus the development of an animal model would help enhance our understanding of this potentially debilitating injury. An appropriate animal model should mimic the conditions of how concussions occur, in that there is not an invasive method to induce the injury and follows the same biomechanics. In our adolescent repetitive mild TBI model, we utilized a free-falling weight to deliver the traumatic blow to anesthetized mice that allowed free head rotation after impact. The injured group received one hit daily over the course of three days. The mice then underwent several behavioral tests to analyze the cognitive deficits, and the pathology of the tissue was analyzed via silver, Hematoxylin and Eosin (H&E), and Fluoro Jade-B staining. The injured mice developed both short- and long-term memory and spatial learning deficits, symptoms commonly found in concussed athletes, but failed to show deficits in anxiety and depression tests. The Fluoro Jade-B, silver and H&E staining resulted in negative signals for cell death. This study properly demonstrates repetitive mild TBIs in an adolescent mice model.

Whether it is in private or professional lives, people are called to make decisions and they tend to seek expert advice. The old adage indicates that more heads are better than one. Receiving more information is often helpful to decisions. However, getting multiple conflicting expert advice might put decision makers in difficult situations. Little is known about their feelings, thinking, and behaviors under such conditions. This research aims to fill the gap and understand the abovementioned consequences of taking multiple conflicting expert advice when making professional (i.e., business or personnel-related) decisions. Using an interview-based qualitative approach, this research sheds light on contextual characteristics where conflicting expert advice may be more beneficial (or harmful), which contributes practical recommendations to improve professional decisions. In sum, this research seeks to verify whether the common wisdom of “more is better” holds up to empirical scrutiny, and suggests that it is “no pain, no gain”.

Subconcussive (SC) impacts have become a growing concern within the neuroscience community regarding the immediate and long-lasting effects of sports-related injuries. While a single low-level impact, i.e., a subconcussion, may not cause cerebral perturbations, it has been increasingly recognized that repeated SC exposure can induce deleterious effects. Therefore, determining the lower limits of systematic perturbation resulting from multiple SC impacts is of critical importance in expanding our understanding of cerebral vulnerability and recovery. Currently, there is a lack of correlation between a mild traumatic brain injury (mTBI) and repeated SC impacts with respect to injury biomechanics. Moreover, the cumulative threshold for repetitive low-level impacts is currently undefined. Thus, this research was designed to determine the pathophysiological differences between a single impact of an mTBI and repeated SC impacts with a subdivided cumulative kinetic energy of the single mTBI impact. In order to address this gap in knowledge, the present investigation employed a surgery-free, closed-head, weight drop injury device capable of producing repeatable, head impacts within a rat model. General locomotion and anxiety-like behavior were assessed using an Open Field Test and motor coordination dysfunction was measured using the rotarod assay. Neuroinflammation was measured using immunohistochemical assessment of astrogliosis (GFAP) and microgliosis (Iba-1) within the hippocampus. Additionally, immunohistochemical assessment of neuronal loss (NeuN) was measured within the hippocampus. To investigate the tolerance and the persistence of cerebral vulnerability following a single mTBI and repeated subconcussive impacts, measurement outcomes were assessed over two-time points (3- and 7-days) post final impact. Although injury groups were not statistically different from their associated sham groups with respect to behavioral outcomes; on average, RSC injury rats displayed a significant increase in anxious-like behavior after 7-days of recovery compared to the single mTBI group. From an inflammatory perspective, both mTBI and RSC injury groups led to extensive microgliosis in the gray matter following 3-days post-impact. Overall, this work’s findings do not provide evidence in support of the notion that repeated subconcussive impacts do result in behavioral disturbances and neuroinflammation, that do not manifest following a single mTBI of the same energy input.