Berns Gregory S, Ashwell Ken W S
Psychology Dept., Emory University, Atlanta, GA United States of America.
Dept. of Anatomy, School of Medical Sciences, University of New South Wales, NSW, Sydney Australia.
PLoS One. 2017 Jan 18;12(1):e0168993. doi: 10.1371/journal.pone.0168993. eCollection 2017.
The last known Tasmanian tiger (Thylacinus cynocephalus)-aka the thylacine-died in 1936. Because its natural behavior was never scientifically documented, we are left to infer aspects of its behavior from museum specimens and historical recollections of bushmen. Recent advances in brain imaging have made it possible to scan postmortem specimens of a wide range of animals, even more than a decade old. Any thylacine brain, however, would be more than 100 years old. Here, we show that it is possible to reconstruct white matter tracts in two thylacine brains. For functional interpretation, we compare to the white matter reconstructions of the brains of two Tasmanian devils (Sarcophilus harrisii). We reconstructed the cortical projection zones of the basal ganglia and major thalamic nuclei. The basal ganglia reconstruction showed a more modularized pattern in the cortex of the thylacine, while the devil cortex was dominated by the putamen. Similarly, the thalamic projections had a more orderly topography in the thylacine than the devil. These results are consistent with theories of brain evolution suggesting that larger brains are more modularized. Functionally, the thylacine's brain may have had relatively more cortex devoted to planning and decision-making, which would be consistent with a predatory ecological niche versus the scavenging niche of the devil.
已知的最后一只塔斯马尼亚虎（袋狼）于1936年死亡。由于其自然行为从未得到科学记录，我们只能从博物馆标本和丛林居民的历史回忆中推断其行为的某些方面。脑成像技术的最新进展使得扫描各种动物的死后标本成为可能，甚至是十多年前的标本。然而，任何袋狼的大脑都有100多年的历史了。在这里，我们表明可以在两个袋狼大脑中重建白质束。为了进行功能解释，我们将其与两只袋獾（袋獾属）大脑的白质重建进行了比较。我们重建了基底神经节和主要丘脑核的皮质投射区。基底神经节的重建显示，袋狼大脑皮质中的模式更加模块化，而袋獾大脑皮质则以壳核为主。同样，丘脑投射在袋狼大脑中的拓扑结构比袋獾的更有序。这些结果与大脑进化理论一致，该理论表明更大的大脑更具模块化。在功能上，袋狼的大脑可能有相对更多的皮质用于规划和决策，这与它作为捕食者的生态位相一致，而袋獾则是食腐动物生态位。
