Spiegel Daniel P, Laguë-Beauvais Maude, Sharma Gaurav, Farivar Reza
Traumatic Brain Injury Program, The Research Institute of the McGill University Health Center, Montréal, Canada; McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montréal, Canada.
Traumatic Brain Injury Program, The Research Institute of the McGill University Health Center, Montréal, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Canada.
Vision Res. 2015 Apr;109(Pt A):38-44. doi: 10.1016/j.visres.2015.02.020. Epub 2015 Mar 6.
Approximately 3.2-5.3 million Americans live with the consequences of a traumatic brain injury (TBI), making TBI one of the most common causes of disability in the world. Visual deficits often accompany TBI but physiological and anatomical evidence for injury in mild TBI is lacking. Axons traversing the corpus callosum are particularly vulnerable to TBI. Hemifield representations of early visual areas are linked by bundles of fibers that together cross the corpus callosum while maintaining their topographic relations. Given the increased vulnerability of the long visual axons traversing the corpus callosum, we hypothesized that inter-hemispheric transmission for vision will be impaired following mild TBI. Using the travelling wave paradigm (Wilson, Blake, & Lee 2001), we measured inter-hemispheric transmission in terms of both speed and propagation failures in 14 mild TBI patients and 14 age-matched controls. We found that relative to intra-hemispheric waves, inter-hemispheric waves were faster and that the inter-hemispheric propagation failures were more common in TBI patients. Furthermore, the transmission failures were topographically distributed, with a bias towards greater failures for transmission across the upper visual field. We discuss the results in terms of increased local inhibition and topographically-selective axonal injury in mild TBI.
约320万至530万美国人承受着创伤性脑损伤（TBI）带来的后果，这使得TBI成为全球最常见的致残原因之一。视觉缺陷常伴随TBI出现，但轻度TBI损伤的生理和解剖学证据尚缺。穿过胼胝体的轴突尤其容易受到TBI的影响。早期视觉区域的半视野表征通过纤维束相连，这些纤维束共同穿过胼胝体，同时保持其拓扑关系。鉴于穿过胼胝体的长视觉轴突的脆弱性增加，我们推测轻度TBI后视觉的半球间传递会受损。我们采用行波范式（Wilson、Blake和Lee，2001年），在14名轻度TBI患者和14名年龄匹配的对照者中，从速度和传播失败两方面测量了半球间传递。我们发现，相对于半球内波，半球间波速度更快，且半球间传播失败在TBI患者中更常见。此外，传递失败呈拓扑分布，偏向于上视野传递失败更多。我们根据轻度TBI中局部抑制增加和拓扑选择性轴突损伤来讨论这些结果。
