Our brains can fathom the beginning of time and the end of the universe, but is any brain capable of understanding itself?

With billions of neurons, each with thousands of connections, one's noggin is a complex, and yes congested, mental freeway. Neurologists and cognitive scientists nowadays are probing how the mind gives rise to thoughts, actions, emotions and ultimately consciousness.

The complex machine is difficult for even the brainiest of scientists to wrap their heads around. But the payoff for such an achievement could be huge.

“If we understand the brain, we will understand both its capacities and its limits for thought, emotions, reasoning, love and every other aspect of human life,” said Norman Weinberger, a neuroscientist at the University of California, Irvine.

Brain teasers

What makes the brain such a tough nut to crack?

According to Scott Huettel of the Center for Cognitive Neuroscience at Duke University, the standard answer to this question goes something like: “The human brain is the most complex object in the known universe ... complexity makes simple models impractical and accurate models impossible to comprehend.”

While that stock answer is correct, Huettel said, it’s incomplete. The real snag in brain science is one of navel gazing. Huettel and other neuroscientists can’t step outside of their own brains (and experiences) when studying the brain itself.

“A more pernicious factor is that we all think we understand the brain—at least our own—through our experiences. But our own subjective experience is a very poor guide to how the brain works,” Huettel told LiveScience.

“Whether the human brain can understand itself is one of the oldest philosophical questions,” said Anders Garm of the University of Copenhagen, Denmark, a biologist who studies jellyfish as models for human neural processing of visual information.

Mental mechanics

Scientists have made some progress in taking an objective, direct “look” at the human brain.

In recent years, brain-imaging techniques, such as functional magnetic resonance imaging (fMRI) have allowed scientists to observe the brain in action and determine how groups of neurons function.

They have pinpointed hubs in the brain that are responsible for certain tasks, such as fleeing a dangerous situation, processing visual information, making those sweet dreams and storing long-term memories. But understanding the mechanics of how neuronal networks collaborate to allow such tasks has remained more elusive.

“We do not yet have a good way to study how groups of neurons form functional networks when we learn, remember, or do anything else, including seeing, hearing moving, loving,” Weinberger said.

Plus these clusters of brain cells somehow give rise to more complex behaviors and emotions, such as altruism, sadness, empathy and anger.

Huettel and his colleagues used fMRIs to discover a region in the brain linked with altruistic behavior.

"Although understanding the function of this brain region may not necessarily identify what drives people like Mother Teresa,” Huettel said, “it may give clues to the origins of important social behaviors like altruism.”

Who am I?

The prized puzzle in brain research is arguably the idea of consciousness. When you look at a painting, for instance, you are aware of it and your mind processes its colors and shapes. At the same time, the visual impression could stir up emotions and thoughts. This subjective awareness and perception is consciousness.

Many scientists consider consciousness the delineation between humans and other animals.

So rather than cognitive processes directly leading to behaviors (unbeknownst to us), we are aware of the thinking. We even know that we know!

If this mind bender is ever solved, an equally perplexing question would arise, according to neuroscientists: Why? Why does awareness exist at all?

Ultimately, Weinberger said, “understanding the brain will enable us to understand what it truly is to be human.”

我们的大脑有领悟时间的开端乃至宇宙的终结的能力，但可有何人的大脑足以理解大脑自身吗？

一个人的脑袋是一个复杂且拥挤的精神“高速公路”，拥有数以十亿计的神经元，并且每个神经元都和数千的神经元相互联系。今天，神经科学家和认知科学家正在探索，大脑如何产生思维、行动、情感以及最关键的意识。

即使，对最聪明的科学家而言，理解缠绕在他们脑袋中的这部复杂机器也是困难的。但如果取得某种进展，回报也必定无比丰厚。

加利福尼亚大学尔湾分校的神经学家，诺曼·温伯格说，“如果我们搞懂了大脑，那我们就能明了，在人类生活的思维、情感、理性和爱情等各方面，大脑的能力和限制。”

大脑戏弄者

是什么让大脑成为如此难砸的死硬坚果？

据杜克大学认知神经科学中心的斯科特·胡特尔的理论，这个问题的标准答案大致如下，
“在已知的宇宙中，人类的大脑是最复杂的东西.....它复杂得让试图解释它的简单模型可笑，让精致的模型无用。”

胡特尔认为，虽然这个平凡的答案是对的，但它并不完整。脑科学研究的客观障碍在于人们只能纸上谈兵。当他们研究的正是大脑自身时，胡特尔和其它神经科学家不可能超越于他们自身的大脑以及经验之外。

胡特尔告诉LiveScience编辑，“更糟糕的是，我们都认为，通过自身体验，至少我们理解自己的大脑。但我们自身的主观体验，在指导我们搞懂大脑如何运作这种事情上，是非常蹩脚的向导。”

安德斯·嘉姆，丹麦哥本哈根大学的一位生物学家，他用水母做模型研究人神经系统处理视觉信号的过程。嘉姆提到，“人的大脑是否能理解它自身，是最古老的哲学问题之一。”

心理机制

科学家在直接“观察”人类大脑，并获得客观认识上，已经取得了一些进展。

近年来，脑成像技术，如功能磁共振成像（fMRI），使科学家能够观察活的，正在运作的大脑，由此确认有多少神经元核团在发挥作用。

科学家已经精确的找到大脑负责特定任务的各中心，如从危险处境中脱身，处理视觉信息，做些美梦以及长期记忆的存储等。但在领会神经元网络如何相互协作以完成这些任务方面，科学家依然一片茫然。

“当我们学习、记忆或者做其它任何事情时，一般都会包含看、听、动、爱等多方面能力，那么神经元核团是如何组织这样的功能网络的？对这类问题，我们一直缺乏有效的研究手段，”温伯格说。

此外，这些成群结队的脑细胞，有时候还会产生相当复杂的行为和情感，如利他主义、悲伤、移情作用以及愤怒。

胡特尔和他的同事利用fMRIs，试图发现大脑中与利他行为有关的区域。

胡特尔说，“尽管搞懂是什么激励着人们，成为德瑞莎修女这样的无私奉献人物，不必非得研究大脑的功能，但这些研究可对重要的社会性行为，如利他主义，提供起源的线索。”

我是谁？

意识这一概念，可以说是脑研究中最重要的问题。例如，当你注视一幅绘画作品时，你意识到它的存在。你的思维处理着它的颜色和形状，与此同时，视觉印象也许还会激发起你的情感和思考。这种主观的感悟和知觉就是意识。

许多科学家认为正是意识，把人类和其它动物相互分隔。

因此，认为是认知过程主宰着我们的行为（我们并不知道是否如此），还不如说是，我们意识到了思维本身。我们甚至知道“我们知道”！

据神经科学家说，如果意识扭曲之谜被解开，即我们知道“我们知道”，将引发一个让人同样困惑的问题：究竟为什么会存在意识？

最后，温伯格总结道，“搞懂了大脑，才能让我们明白究竟何以为人。”