Mild traumatic brain injury (mTBI) is a major cause of morbidity and mortality with a poorly understood pathophysiology. Animal models have been increasingly utilized to better understand mTBI and recent research has identified visual deficits in these models that correspond to human literature. While visual impairment is being further characterized within TBI, the implications of impaired vision on behavioral tasks commonly utilized in animal models has not been well described thus far. Visual deficits may well confound behavioral tests that are believed to be isolated to cognitive functioning such as learning and memory. We utilized a mouse model of repetitive mTBI (rmTBI) to further characterize visual deficits using an optomotor task, electroretinogram, and visually evoked potential, and located likely areas of damage to the visual pathway. Mice were tested on multiple behavioral metrics, including a touchscreen conditional learning task to better identify the contribution of visual dysfunction to behavioral alterations. We found that rmTBI caused visual dysfunction resulting from damage distal to the retina that likely involves pathology within the optic nerve. Moreover, loss of vision led to poorer performance of rmTBI animals on classic behavioral tests such as the Morris water maze that would otherwise be attributed solely to learning and memory deficits. The touchscreen conditional learning task was able to differentiate rmTBI induced learning and memory dysfunction from visual impairment and is a valuable tool for elucidating subtle changes resulting from TBI.

中文翻译：

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小鼠模型中重复性轻度创伤性脑损伤后的视觉功能障碍及其对行为指标的影响


轻度创伤性脑损伤（mTBI）是发病和死亡的主要原因，但其病理生理学知之甚少。动物模型越来越多地被用来更好地理解 mTBI，最近的研究发现这些模型中存在与人类文献相对应的视觉缺陷。虽然视觉障碍在 TBI 中得到了进一步的表征，但迄今为止，视力障碍对动物模型中常用的行为任务的影响尚未得到很好的描述。视觉缺陷很可能会混淆行为测试，这些测试被认为与学习和记忆等认知功能无关。我们利用重复性 mTBI (rmTBI) 小鼠模型，通过视运动任务、视网膜电图和视觉诱发电位进一步表征视觉缺陷，并定位视觉通路可能受损的区域。对小鼠进行了多种行为指标测试，包括触摸屏条件学习任务，以更好地识别视觉功能障碍对行为改变的影响。我们发现 rmTBI 会因视网膜远端损伤而导致视觉功能障碍，这可能涉及视神经内的病变。此外，视力丧失导致 rmTBI 动物在莫里斯水迷宫等经典行为测试中表现较差，否则这些测试只能归因于学习和记忆缺陷。触摸屏条件学习任务能够区分 rmTBI 引起的学习和记忆功能障碍与视觉障碍，并且是阐明 TBI 引起的细微变化的宝贵工具。