啄木鸟如何在反复的高强度冲击中存活而不造成脑损伤?

啄木鸟如何在反复的高强度冲击中存活而不造成脑损伤?

Slamming a beak against the trunk of a tree would seem like an activity that would cause headaches, jaw aches and serious neck and brain injuries. Yet woodpeckers can do this 20 times per second and suffer no ill effects.

用喙撞击树干似乎会导致头痛、下巴疼痛以及严重的颈部和脑部损伤。然而，啄木鸟可以做到20次/每秒，并且没有任何不良影响。

Woodpeckers are found in forested areas worldwide, except in Australia. These birds have the unusual ability to use their beaks to hammer into the trunks of trees to make holes to extract insects and sap. Even more impressive they do this without hurting themselves.

啄木鸟在世界各地的森林地区都有发现，除了澳大利亚。这些鸟有一种不寻常的能力，用它们的喙敲进树干，钻出洞来吸取昆虫和汁液。更令人印象深刻的是，它们这样做的时候并没有伤害到自己。

We are materials scientists who study biological substances like bones, skins, feathers and shells found in nature. We are interested in the skull and tongue bone structure of woodpeckers, because we think their unusual anatomy could yield insights that could help researchers develop better protective head gear for humans.

我们是研究自然界中发现的骨骼、皮肤、羽毛和贝壳等生物物质的材料科学家。我们对啄木鸟的头骨和舌骨结构很感兴趣，因为我们认为它们不同寻常的解剖结构可以帮助研究人员开发出更好的保护人类头部的装备。

Concussions in people

脑震荡的人

Woodpeckers endure many high impact shocks to their heads as they peck.

啄木鸟在啄食时，头部会受到许多强烈的撞击。

They have strong tail feathers and claws that help them keep their balance as their head moves toward the tree trunk at 7 meters (23 feet) per second. Then, when their beak strikes, their heads slow down at about 1,200 times the force of gravity (g).

它们有强壮的尾羽和爪子，当它们的头以每秒7米(23英尺)的速度向树干移动时，这些羽毛和爪子可以帮助它们保持平衡。然后，当它们的喙撞击时，它们的头部会以1200倍重力(g)的速度减速。

All of this occurs without the woodpecker sustaining concussions or brain damage.

所有这些都发生在啄木鸟没有持续脑震荡或脑损伤的情况下。

A concussion is a form of traumatic brain injury caused by repeated blows to the head. It is a common occurrence and happens frequently during contact sports like football or hockey.

脑震荡是一种由反复击打头部造成的创伤性脑损伤。这是一种常见的现象，经常发生在接触性运动中，如足球或曲棍球。

Repeated traumatic brain injury eventually causes a progressive brain disorder, chronic traumatic encephalopathy (CTE), which is irreversible and results in symptoms such as memory loss, depression, impulsivity, aggressiveness and suicidal behavior.

反复的创伤性脑损伤最终会导致进行性脑功能障碍，即慢性创伤性脑病(CTE)，这是不可逆转的，会导致记忆丧失、抑郁、冲动、攻击性和自杀行为等症状。

The National Football League says concussions in football players occur at 80 g. So how do woodpeckers survive repeated 1,200 g impacts without harming their brain?

美国国家橄榄球联盟称橄榄球运动员的脑震荡发生在80克。那么，啄木鸟是如何在不伤害大脑的情况下，承受1200克的反复撞击的呢?

We have looked for the key secrets of the woodpecker's ability to tolerate the high impact during the hammering. We studied the micro-structures of bones and then did a biomechanical analysis on the head.

我们已经找到了啄木鸟在锤击过程中承受高冲击能力的关键秘密。我们研究了骨骼的微观结构，然后对头部进行了生物力学分析。

Unusual skull bone and tongue bone structures

不寻常的头骨和舌骨结构

By comparing the skulls of woodpeckers and chickens, we discovered that woodpeckers have impact-absorbing adaptations that other birds do not have. This includes specialized skull bones, neck muscles, beaks and tongue bones.

通过比较啄木鸟和鸡的头骨，我们发现啄木鸟有其他鸟类没有的吸收冲击力的适应性。这包括特殊的头骨、颈部肌肉、喙和舌骨。

The skull bones have a different chemical composition and density. For example, one structural adaptation is achieved through increasing the accumulation of minerals in the bones to make them stiffer and stronger compared to other birds.

头骨有不同的化学成分和密度。例如，一种结构上的适应是通过增加骨骼中矿物质的积累来实现的，从而使它们比其他鸟类更坚硬、更强壮。

Surprisingly, the skull bone is very thin and there is less fluid that separates the brain from the skull bone than in other birds and animals. That would suggest that the skull is adapted to be harder and tougher at the same time.

令人惊讶的是，与其他鸟类和动物相比，啄木鸟的头骨非常薄，大脑和头骨之间的液体更少。这表明，同样情况下啄木鸟的头骨能适应更硬的材质。

Typically in the real-world materials science, there is a general trade-off between hardness and toughness. However, having both hard and tough materials on the head lessens the amount of impact transferred to the brain.

通常在真实世界的材料科学中，在硬度和韧性之间有一个普遍的平衡。然而，在头部放置硬的和硬的材料会减少传递到大脑的冲击力。

A second different is that woodpeckers have less internal fluid surrounding the brain than other big animals. This helps to limit the motion of the brain during the pecking. The reduced amount of fluid has an effect that is analogous to the yolk of a hard-boiled egg, which won't get damaged by shaking, compared to the yolk of a raw, uncooked egg.

另一个不同之处在于，啄木鸟大脑周围的内部液体比其他大型动物要少。这有助于限制啄食时大脑的运动。减少的液体量产生的效果类似于煮熟的鸡蛋的蛋黄，与生的、未煮熟的鸡蛋的蛋黄相比，它不会因为摇晃而受损。

Woodpeckers also have a bone embedded in their tongue that helps to extract insects from the trees. The unusual tongue wraps around the back of the skull and anchors at the front between the eyes. This configuration lets the tongue and its bone act as a spring, dampening the physical force and related vibrations.

啄木鸟的舌头上还嵌有一根骨头，可以帮助它们从树上捕食昆虫。这种不寻常的舌头包裹着头骨的后部，位于两眼之间的前部。这种结构让舌头和它的骨头充当弹簧，减弱物理力和相关的振动。

Different types of bone

不同类型的骨骼

The stiffness and strength of a typical skeletal bone is due to a dense sheath of compact bone that encapsulated a porous, spongy bone. But the woodpecker's tongue bone has the opposite structure: a flexible sheath and a harder core bone. This inside-out configuration provides better flexibility and can absorb higher impacts and vibrations.

典型的骨骼的硬度和强度是由于致密的骨鞘包裹着多孔的海绵状骨。但啄木鸟的舌骨却有相反的结构:一个灵活的鞘和一个坚硬的核心骨。这种由内而外的结构提供了更好的灵活性，可以吸收更高的冲击和振动。

Our work suggests that the woodpecker's unusual skull and tongue bones are an example of impact-resistant structures essential for protecting the woodpecker's brain during pecking behavior.

我们的研究表明，啄木鸟不同寻常的头骨和舌骨，是在啄木鸟啄木行为时保护其大脑所必需的抗撞击结构的一个因素。

Currently, biologists and neuroscientists are actively working on studying the woodpecker's brain to see if there is any pathological evidence of brain injuries – like CTE in humans.

目前，生物学家和神经科学家正在积极研究啄木鸟的大脑，以确定是否存在脑损伤的病理证据——比如人类的CTE。

We hope this research reveals whether there are other protective or healing mechanisms at play at the level of tissues or cells in woodpecker brains which will, we hope, reveal how to protect and heal human brain injuries.

我们希望这项研究能揭示啄木鸟大脑组织或细胞层面是否存在其他保护或愈合机制，从而揭示如何保护和治愈人类大脑损伤。