Grant: Master's Award: Canada Graduate Scholarships

Traumatic brain injuries are a devastatingly common issue facing Canadian healthcare. They are the leading cause of death and disability in people under the age of 45. Around 80% of brain injuries are concussions, which can happen when the head hits, or is hit by another object. Concussions can lead to a variety of symptoms such as dizziness, confusion, nausea, fatigue, disrupted balance, impaired learning, and memory loss. These symptoms typically disappear within several weeks of the injury, but in some cases they can persist. Interestingly, research has shown that symptoms tend to last longer in children. This may be because developing brains are more prone to damage by head injury. Symptoms also appear to last longer in females, although it is not clear why this is true. There is no treatment that can entirely cure damage caused by concussions, and our diagnostic tools are limited. This becomes problematic because receiving a second concussion before the first injury has healed can cause more severe and longer lasting damage. Continued research is needed in order to fully understand how concussions affect brain cells and cause symptoms such as learning and memory loss. This basic knowledge is critical for establishing new treatments and diagnostic tools. The purpose of this research is to determine how concussions affect learning and memory in juvenile rats, and whether this is different in males and females. I will study this research question by mimicking a concussion in young male and female rats, and then testing their performance in learning and memory tasks. I will also look at how a concussion affects brain cells in the hippocampus, which is the part of the brain that controls learning and memory. I am going to focus on two cellular processes that may be initiated by brain injury. The first, known as oxidative stress, takes place when cells overproduce molecules called reactive oxygen species, which can damage cells and their components. The second, known as mitochondrial dysfunction, occurs when mitochondria, the main energy producing component of cells, stop working properly. These processes are linked because reactive oxygen species can damage mitochondria, and these damaged mitochondria can overproduce reactive oxygen species. These processes might play a role in learning and memory loss after concussions because they can both impair the way brain cells communicate, and in extreme cases they can both lead to brain cell death. Since there is a striking need for better treatment options I would also like to determine whether dietary supplementation with Vitamin E and Vitamin C can help to rescue learning and memory loss after concussions. These might be promising as treatments because they are antioxidants, which combat damage from reactive oxygen species and reduce oxidative stress. Importantly, they are easily administered and harmless in proper doses. The proposed research is important because expanding our understanding of the cellular processes that lead to learning and memory deficits after concussions can help find new treatments and diagnostic tools. Determining whether these processes are different in males and females, and in children will help to develop more specialized treatments.