Advances inneuroscience和工程为卢克斯波德的人产生了很大的希望prosthetics:机器人设备这几乎无法区分来自人肢。解决这一挑战的关键是设计不仅可以使用用户自己的神经活动运行的设备，而且还可以准确且精确地接收和中继到用户的感官信息。
神经科学家在芝加哥大学和查尔摩工业大学的新研究，突出了这可能是多么困难。在三个受试者的群组中，截肢肢体已被神经肌肉骨骼假肢所取代，调查人员发现即使在使用这些设备的全年之后，参与者的主观感觉从未转移以匹配的位置touch sensorson their prosthetic devices.
触摸感觉的稳定性突出了神经系统适应不同感官输入的能力的限制。
肘部截肢的三位参与者配备了高科技神经调节剂devices that were affixed directly to their humerus bone. The users could control the prosthetic device thanks to signals received from electrodes implanted in the residual arm muscles, and received sensory feedback via another set of implanted electrodes. A sensor located on the prosthetic thumb triggered stimulation of the nerve, which in turn elicited a touch sensation.
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然而，由于神经的组织基本上是任意的，外科医生无法确定它们的电极是否会在拇指上的正确位置产生感觉。在研究中，假肢用户没有报告拇指上的感觉，而是在其他手部门，例如他们的中指或手掌。
Participants then wore the prosthesis for upwards of 12 hours a day, every day, using it to manipulate objects during their daily routine for over a year.
“一个问题with current neural electrodes is that you can’t tell during the implantation手术which part of the nerve corresponds to what sensation, so the electrodes don’t always land in exactly the location in the nerve that would match the location of the sensors in theprosthetic hand,” said lead author and developer of the neuromusculoskeletal prostheses, Max Ortiz Catalan, PhD, an associate professor of bionics at Chalmers University of Technology and Director of the Center for Bionics and Pain Research in Gothenburg, Sweden.
“我们希望由于患者抓住物体并在手中的其他地方感到感觉，整天和每天都有几个月，大脑会通过将感知感到拇指转移来解决不匹配，”他继续。
Despite being able to observe their hand while interacting with objects, none of the users ever reported that they felt the sensation on their thumb, but rather that the sensation persisted in the same area where it was originally felt.
“每天，每年一年，这些科目都看到了他们的假体拇指感动，并在不同的位置感受到它 - 有时靠近拇指，但不在它上 - 并且感觉永远不会萌芽。甚至不是一个SMIDGE，“高级作者Sliman Bensmaia，博士，詹姆斯和克伦弗兰克家庭教授在Uchicago的有机体生物学和解剖学教授。
这些结果挑战肢体损失后大脑可塑性的盛行教条。许多人认为大脑在失去感觉输入后重新组织本身的高能力，共同为其他目的共同服用现有的未使用的脑组织。
“有这种想法是，神经系统真的是塑料，所以如果你在你看到的东西之间看到了一个不匹配，这是神经重复的一个很好的机会，”Bensmaia说。“例如，如果你一起缝了两个手指并看看大脑中的那样，他们似乎合并了。”
“But I think that this idea has been vastly overstated. It’s less like you’re reorganizing a room and more like you’re just hearing echoes bouncing around an empty chamber,” he continued. “You might get some overlapping sensation from adjacent limbs, but it’s just because the area of the brain that used to respond to sensation is empty, and activating the neurons around it leads to an echo through the emptiness.”
This study highlights the importance of knowing exactly where to place electrodes when implanting sensory arrays for patients using these types of neuroprosthetic devices, as it appears unlikely that the brain is capable of making substantial adjustments in how it perceives that sensory input. “This means that you really have to get it right,” said Bensmaia. “There are no do-overs here.”
该研究发表于Cell Reports.
