Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-5230, USA.
Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, 11794-8081, USA.
J Neurosci Methods. 2019 Apr 1;317:157-164. doi: 10.1016/j.jneumeth.2019.01.017. Epub 2019 Jan 30.
Birds comprise the most diverse group of terrestrial vertebrates. This success likely is related to the evolution of powered flight over 75 mya. Modern approaches for studying brain function, however, have yet to be fully adapted and applied to birds, especially as they relate to specific behaviors including flight. New method: We have developed a comprehensive set of in vivo experimental methods utilizing PET imaging with F-18 labeled fluorodeoxyglucose (FDG) to study regional changes in metabolism specifically related to flight, yet applicable to other behaviors as well. It incorporates approaches for selection of species, behavioral/imaging paradigm, animal preparation, radiotracer injection route, image quantification, and image analysis via an enhanced brain atlas. We also carried out preliminary modeling studies to better understand tracer kinetics.
The methods were successful in identifying brain regions statistically associated with flight using only 8 animals. Peak brain uptake of FDG between birds and rodents is similar despite much higher blood glucose levels in birds. We also confirmed that brain uptake of FDG steadily decreases after the initial peak and provide evidence that it may be related to greater dephosphorylation of FDG phosphate than that observed in mammals. Comparison with existing methods: FDG PET has been used in only a few studies of the bird brain. We introduce a new species, more realistic flight behavior, paired (test/retest) design, and improved quantification and analysis approaches.
The proposed imaging protocol is non-invasive yet sensitive to regional metabolic changes in the bird brain related to behavior.
鸟类是陆地脊椎动物中最多样化的群体。这种成功可能与 7500 万年前的动力飞行进化有关。然而，现代研究大脑功能的方法尚未完全适用于鸟类，尤其是与飞行等特定行为相关的方法。新方法：我们开发了一套全面的体内实验方法，利用正电子发射断层扫描 (PET) 成像和 F-18 标记氟脱氧葡萄糖 (FDG) 来研究与飞行相关的特定代谢的区域变化，同时也适用于其他行为。它结合了选择物种、行为/成像范式、动物准备、示踪剂注射途径、图像定量和通过增强脑图谱进行图像分析的方法。我们还进行了初步的建模研究，以更好地了解示踪剂动力学。
该方法仅使用 8 只动物成功地确定了与飞行相关的统计学上显著的大脑区域。尽管鸟类的血糖水平高得多，但鸟类和啮齿动物之间 FDG 的大脑摄取峰值相似。我们还证实，FDG 的大脑摄取在初始峰值后逐渐下降，并提供了证据表明，它可能与 FDG 磷酸的去磷酸化程度大于哺乳动物观察到的程度有关。与现有方法的比较：FDG PET 仅在少数鸟类大脑研究中使用过。我们引入了一个新的物种，更现实的飞行行为，配对（测试/重测）设计，以及改进的定量和分析方法。
所提出的成像方案是非侵入性的，但对与行为相关的鸟类大脑的区域代谢变化敏感。
