“阿凡达”式幻想成真 美科学家利用猴子实现异体控制

在美国科幻电影《阿凡达》中，双腿瘫痪的男主角可以通过意识控制克隆外星人“阿凡达”的躯体外出探险。如今，这一虚幻的场景成为现实。

近日，美国科学家成功利用一只猴子发出指令、进而控制另一只猴子完成动作。这种“异体控制”技术将为瘫痪病人带来福音。

实验过程中，研究人员先在“主体”猴子的大脑中植入一个芯片，对多达100个神经元的电活动进行监控，并记录它支配每个身体动作时的大脑神经元电活动。而“阿凡达”猴子的脊髓中则植入了36个电极，尝试刺激不同的电极组合及其对肢体运动产生的影响。

随后，“阿凡达”猴子服用镇静剂，进入人工瘫痪状态。研究人员将两只猴子身上的仪器连接起来，使得“主体”猴子的大脑活动能够实时控制“阿凡达”猴子身体动作。

按照试验流程，“主体”猴子被限制在一张特殊的座椅上，它面前有一个电脑屏幕，屏幕上有一个光标和一个在两点之间上下移动的绿色圆圈。此时，位于别处的“阿凡达”猴子已经完全瘫痪，它的手上握有一个可360度转向的操纵杆。这个操纵杆用来控制屏幕上的光标，以追逐目标绿色圆圈。

当“主体”猴子想要移动光标时，它的大脑神经信号被计算机解码并实时传送至“阿凡达”猴子的脊髓。此时，“阿凡达”猴子就能依据指令移动操纵杆，如果操作正确，“主体”猴子就能得到一杯果汁作为奖励。实验结果显示，两只猴子协作完成任务的成功率高达98%。

“我们的终极目标是，利用这项技术使瘫痪人士重获完全自然运动的能力。”一位研究人员说，“我认为这在理论上是可行的，不过还需要更多努力才能实现。”

It may sound like the kind of mind control seen in sci-fi film Avatar, but scientists working on a cure for paralysis have successfully used the thoughts of one monkey to control the movement of another.

The study's co-author, Maryam Shanechi of Cornell University's School of Electrical and Computer Engineering, said: We demonstrate that a subject can control a paralysed limb purely with its thoughts.'

The discovery 'could have the potential to help paralysed patients regain control of their own limbs,' she added.

The master had a brain chip implanted that could monitor the activity of up to 100 neurons.

During training, the physical actions of the monkey were matched up with the patterns of electrical activity in the neurons.

The avatar had 36 electrodes implanted in the spinal cord and tests were performed to see how stimulating different combinations of electrodes affected movement.

The two monkeys were then hooked up so that the brain scans in one controlled movements in real time in the other.

A computer then decoded and relayed neural signals between the two.

The first monkey, dubbed the 'master', was restrained in a special chair in front of a computer screen showing a cursor and a green circle alternating between two spots.

The second animal, or 'avatar', was fully sedated in a separate enclosure with its arm strapped to a 360-degree joystick.

This joystick was used to move the cursor, and chase the circular target, on the screen in front of the 'master.'

As the 'master' thought of moving the cursor, its brain signals were decoded to determine which of the two targets it had in mind.

This data was relayed in real-time to the spinal cord of the sleeping avatar, whose arm manipulated the joystick accordingly.

Every time the cursor hit its target, the master received a squirt of juice as reward.

In 98% of tests, the master could correctly control the avatar's arm.

One of the researchers said: "The goal is to take people with brain stem or spinal cord paralysis and bypass the injury.

"The hope is ultimately to get completely natural movement, I think it's theoretically possible, but it will require an exponential additional effort to get to that point."