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.”

我們的大腦有領(lǐng)悟時(shí)間的開(kāi)端乃至宇宙的終結(jié)的能力，但可有何人的大腦足以理解大腦自身嗎？

一個(gè)人的腦袋是一個(gè)復(fù)雜且擁擠的精神“高速公路”，擁有數(shù)以十億計(jì)的神經(jīng)元，并且每個(gè)神經(jīng)元都和數(shù)千的神經(jīng)元相互聯(lián)系。今天，神經(jīng)科學(xué)家和認(rèn)知科學(xué)家正在探索，大腦如何產(chǎn)生思維、行動(dòng)、情感以及最關(guān)鍵的意識(shí)。

即使，對(duì)最聰明的科學(xué)家而言，理解纏繞在他們腦袋中的這部復(fù)雜機(jī)器也是困難的。但如果取得某種進(jìn)展，回報(bào)也必定無(wú)比豐厚。

加利福尼亞大學(xué)爾灣分校的神經(jīng)學(xué)家，諾曼·溫伯格說(shuō)，“如果我們搞懂了大腦，那我們就能明了，在人類(lèi)生活的思維、情感、理性和愛(ài)情等各方面，大腦的能力和限制。”

大腦戲弄者

是什么讓大腦成為如此難砸的死硬堅(jiān)果？

據(jù)杜克大學(xué)認(rèn)知神經(jīng)科學(xué)中心的斯科特·胡特爾的理論，這個(gè)問(wèn)題的標(biāo)準(zhǔn)答案大致如下，
“在已知的宇宙中，人類(lèi)的大腦是最復(fù)雜的東西.....它復(fù)雜得讓試圖解釋它的簡(jiǎn)單模型可笑，讓精致的模型無(wú)用。”

胡特爾認(rèn)為，雖然這個(gè)平凡的答案是對(duì)的，但它并不完整。腦科學(xué)研究的客觀(guān)障礙在于人們只能紙上談兵。當(dāng)他們研究的正是大腦自身時(shí)，胡特爾和其它神經(jīng)科學(xué)家不可能超越于他們自身的大腦以及經(jīng)驗(yàn)之外。

胡特爾告訴LiveScience編輯，“更糟糕的是，我們都認(rèn)為，通過(guò)自身體驗(yàn)，至少我們理解自己的大腦。但我們自身的主觀(guān)體驗(yàn)，在指導(dǎo)我們搞懂大腦如何運(yùn)作這種事情上，是非常蹩腳的向?qū)А?rdquo;

安德斯·嘉姆，丹麥哥本哈根大學(xué)的一位生物學(xué)家，他用水母做模型研究人神經(jīng)系統(tǒng)處理視覺(jué)信號(hào)的過(guò)程。嘉姆提到，“人的大腦是否能理解它自身，是最古老的哲學(xué)問(wèn)題之一。”

心理機(jī)制

科學(xué)家在直接“觀(guān)察”人類(lèi)大腦，并獲得客觀(guān)認(rèn)識(shí)上，已經(jīng)取得了一些進(jìn)展。

近年來(lái)，腦成像技術(shù)，如功能磁共振成像（fMRI），使科學(xué)家能夠觀(guān)察活的，正在運(yùn)作的大腦，由此確認(rèn)有多少神經(jīng)元核團(tuán)在發(fā)揮作用。

科學(xué)家已經(jīng)精確的找到大腦負(fù)責(zé)特定任務(wù)的各中心，如從危險(xiǎn)處境中脫身，處理視覺(jué)信息，做些美夢(mèng)以及長(zhǎng)期記憶的存儲(chǔ)等。但在領(lǐng)會(huì)神經(jīng)元網(wǎng)絡(luò)如何相互協(xié)作以完成這些任務(wù)方面，科學(xué)家依然一片茫然。

“當(dāng)我們學(xué)習(xí)、記憶或者做其它任何事情時(shí)，一般都會(huì)包含看、聽(tīng)、動(dòng)、愛(ài)等多方面能力，那么神經(jīng)元核團(tuán)是如何組織這樣的功能網(wǎng)絡(luò)的？對(duì)這類(lèi)問(wèn)題，我們一直缺乏有效的研究手段，”溫伯格說(shuō)。

此外，這些成群結(jié)隊(duì)的腦細(xì)胞，有時(shí)候還會(huì)產(chǎn)生相當(dāng)復(fù)雜的行為和情感，如利他主義、悲傷、移情作用以及憤怒。

胡特爾和他的同事利用fMRIs，試圖發(fā)現(xiàn)大腦中與利他行為有關(guān)的區(qū)域。

胡特爾說(shuō)，“盡管搞懂是什么激勵(lì)著人們，成為德瑞莎修女這樣的無(wú)私奉獻(xiàn)人物，不必非得研究大腦的功能，但這些研究可對(duì)重要的社會(huì)性行為，如利他主義，提供起源的線(xiàn)索。”

我是誰(shuí)？

意識(shí)這一概念，可以說(shuō)是腦研究中最重要的問(wèn)題。例如，當(dāng)你注視一幅繪畫(huà)作品時(shí)，你意識(shí)到它的存在。你的思維處理著它的顏色和形狀，與此同時(shí)，視覺(jué)印象也許還會(huì)激發(fā)起你的情感和思考。這種主觀(guān)的感悟和知覺(jué)就是意識(shí)。

許多科學(xué)家認(rèn)為正是意識(shí)，把人類(lèi)和其它動(dòng)物相互分隔。

因此，認(rèn)為是認(rèn)知過(guò)程主宰著我們的行為（我們并不知道是否如此），還不如說(shuō)是，我們意識(shí)到了思維本身。我們甚至知道“我們知道”！

據(jù)神經(jīng)科學(xué)家說(shuō)，如果意識(shí)扭曲之謎被解開(kāi)，即我們知道“我們知道”，將引發(fā)一個(gè)讓人同樣困惑的問(wèn)題：究竟為什么會(huì)存在意識(shí)？

最后，溫伯格總結(jié)道，“搞懂了大腦，才能讓我們明白究竟何以為人。”