TED演讲：拥有大脑的真正原因(7)

 　　But you can imagine looking inside the brain. And here's inside the brain.  不过我们能想象大脑内部发生了什么。图上就是大脑内部。

　　You might have a little predictor, a neural¹ simulator, of the physics of your body and your senses.  里面可能有一个预测结构，也就是神经组成的模拟器来模拟身体和感觉器官的物理过程。

　　So as you send a movement command down, you tap a copy of that off and run it into your neural simulator to anticipate the sensory² consequences of your actions.  当一个动作指令发出来的时候，大脑复制一份这个指令，然后在这个神经模拟器上运行，来预测出这个动作带来的感官回馈结果。

　　So as I shake this ketchup³ bottle, I get some true sensory feedback as the function of time in the bottom row.  所以我往下磕这个番茄酱瓶子的时候，在下面那行里我得到真实的感官回馈，是个关于时间的函数。

　　And if I've got a good predictor, it predicts the same thing. 同时大脑里的预测结构如果准确的话，也预测出了同样的结果。

　　Well why would I bother doing that?  好了，那我为什么非要多此一举来预测呢？

　　I'm going to get the same feedback anyway. Well there's good reasons.  毕竟最终我总能得到同样的回馈。不过这样确实是有原因的。

　　Imagine, as I shake the ketchup bottle, someone very kindly⁴ comes up to me and taps it on the back for me.  想象我磕这个番茄酱瓶子的时候，台下有位热心观众过来帮我拍了下瓶底。

　　Now I get an extra source of sensory information due to that external act.  于是我多了一个感官信息的来源因为我多接受了这个外在的动作。

　　So I get two sources.  所以感官回馈现在有两个来源。

　　I get you tapping on it, and I get me shaking it, but from my senses' point of view, that is combined together into one source of information. 一个是你拍瓶底的动作，另一个是我磕瓶子的动作，但是从我的感觉来讲，这两个是合起来作为一个信息源的。

　　Now there's good reason to believe that you would want to be able to distinguish external events from internal events.  可是我们有理由相信，我们希望能够把外来事件和内在的事件区分开。

　　Because external events are actually much more behaviorally relevant than feeling everything that's going on inside my body.  因为实际上相对于我身体上发生的内在事件，外来事件在行为上才更有分析价值。

　　So one way to reconstruct that is to compare the prediction -- which is only based on your movement commands -- with the reality.  所以区分开来的一种办法就是把我的预测结果--因为这个结果只基于我的动作指令--和真实的感官反馈做比较。

　　Any discrepancy⁵ should hopefully be external.  希望两者的差值应该就是外力的结果。

　　So as I go around the world, I'm making predictions of what I should get, subtracting them off.  所以我和外界接触的时候，我预测出我自己的动作可能得到什么回馈，减掉这些。

　　Everything left over is external to me. 剩下的其他部分就是外界对我的产生的作用。

1 neural   

adj.神经的，神经系统的

参考例句：

• The neural network can preferably solve the non- linear problem.利用神经网络建模可以较好地解决非线性问题。
• The information transmission in neural system depends on neurotransmitters.信息传递的神经途径有赖于神经递质。

2 sensory   

adj.知觉的，感觉的，知觉器官的

参考例句：

• Human powers of sensory discrimination are limited.人类感官分辨能力有限。
• The sensory system may undergo long-term adaptation in alien environments.感觉系统对陌生的环境可能经过长时期才能适应。

3 ketchup   

n.蕃茄酱，蕃茄沙司

参考例句：

• There's a spot of ketchup on the tablecloth.桌布上有一点番茄酱的渍斑。
• Could I have some ketchup and napkins,please?请给我一些番茄酱和纸手巾？

4 kindly   

adj.和蔼的，温和的，爽快的；adv.温和地，亲切地

参考例句：

• Her neighbours spoke of her as kindly and hospitable.她的邻居都说她和蔼可亲、热情好客。
• A shadow passed over the kindly face of the old woman.一道阴影掠过老太太慈祥的面孔。

5 discrepancy   

n.不同；不符；差异；矛盾

参考例句：

• The discrepancy in their ages seemed not to matter.他们之间年龄的差异似乎没有多大关系。
• There was a discrepancy in the two reports of the accident.关于那次事故的两则报道有不一致之处。