“阿凡達”式幻想成真 美科學家利用猴子實現異體控制

在美國科幻電影《阿凡達》中，雙腿癱瘓的男主角可以通過意識控制克隆外星人“阿凡達”的軀體外出探險。如今，這一虛幻的場景成爲現實。

近日，美國科學家成功利用一隻猴子發出指令、進而控制另一隻猴子完成動作。這種“異體控制”技術將爲癱瘓病人帶來福音。

實驗過程中，研究人員先在“主體”猴子的大腦中植入一個芯片，對多達100個神經元的電活動進行監控，並記錄它支配每個身體動作時的大腦神經元電活動。而“阿凡達”猴子的脊髓中則植入了36個電極，嘗試刺激不同的電極組合及其對肢體運動產生的影響。

隨後，“阿凡達”猴子服用鎮靜劑，進入人工癱瘓狀態。研究人員將兩隻猴子身上的儀器連接起來，使得“主體”猴子的大腦活動能夠實時控制“阿凡達”猴子身體動作。

按照試驗流程，“主體”猴子被限制在一張特殊的座椅上，它面前有一個電腦屏幕，屏幕上有一個光標和一個在兩點之間上下移動的綠色圓圈。此時，位於別處的“阿凡達”猴子已經完全癱瘓，它的手上握有一個可360度轉向的操縱桿。這個操縱桿用來控制屏幕上的光標，以追逐目標綠色圓圈。

當“主體”猴子想要移動光標時，它的大腦神經信號被計算機解碼並實時傳送至“阿凡達”猴子的脊髓。此時，“阿凡達”猴子就能依據指令移動操縱桿，如果操作正確，“主體”猴子就能得到一杯果汁作爲獎勵。實驗結果顯示，兩隻猴子協作完成任務的成功率高達98%。

“我們的終極目標是，利用這項技術使癱瘓人士重獲完全自然運動的能力。”一位研究人員說，“我認爲這在理論上是可行的，不過還需要更多努力才能實現。”

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."