Mild Traumatic Brain Injuries and Object Recognition

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality amongst young people worldwide. Falls, assaults, motor vehicle accidents, and other external factors all can contribute to TBI–a complex neurological condition and pathophysiological process that can impact and damage a wide variety of brain functions. TBI is considered one of the most frequent neurological conditions with unmet clinical needs in the treatment and management of TBI patients. A majority of those who experience TBI are actually impaired with mild traumatic brain injury (mTBI). The term “mild” refers to the severity of the initial injury rather than the severity of its consequences, which can include cognitive and behavioural deficits lasting from months to years. mTBI has been linked to the development of neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease, as well as the development of chronic traumatic encephalopathy. As part of efforts to understand mTBI's impact on neurocognitive function, a number of distinct experimental methods have emerged that model mTBI in rodents. One of the most widely used models is the novel object recognition (NOR) test, which utilizes rodents’ innate tendency to explore novel objects to draw conclusions about memory dysfunction after mTBI. Memory dysfunction and impaired recognition memory are prominent symptoms of mTBI, making the NOR test an ideal medium for evaluating the injury's effects. This chapter provides an overview of various TBI-induced NOR models in the scientific literature. In general, the literature finds a decrease in NOR performance after TBI in rodents. This finding supports the sensitivity of NOR tests and lends credence to the convergence of a large number of results obtained with various TBI-induced methodologies. This chapter includes a number of studies in which recognition memory seems unaffected after TBI; this could be due to differences in TBI parameters as well as differences in NOR testing procedures and assessment methods. These discrepancies merit further considerations as the treatment for TBI continues to be investigated.