2022年经济学人 提升成年人大脑记忆力的方法(1)

 

How adult brains learn the new without forgetting the old.

成年人的大脑如何在不忘记旧内容的情况下学习新内容。

Learning new things is hard.

学习新事物很难。

Remembering what has already been learned is harder.

记住已经学过的东西更难。

Any successful learning system, be it a brain or a piece of artificial-intelligence software, must strike the right balance between stability and flexibility¹.

任何成功的学习系统，无论是大脑还是人工智能软件，都必须在稳定性和可塑性之间取得适当的平衡。

It must be stable enough to remember important old things yet flexible enough to learn new ones without destroying old memory traces - preferably for as long as it exists.

它必须足够稳定，能够保留过往重要的记忆，也必须足够可塑，以便在不影响过往记忆痕迹的情况下学习新事物——最好是在过往记忆存在的时间内。

Learning is a result of changes in the pattern of neural² connectivity in the brain.

学习是大脑中神经连接模式改变的结果。

Each connection between nerve cells, called a synapse³, is a tiny gap between the ends of branches ramifying from such cells.

神经细胞之间的连接被称为突触，突触是神经细胞末梢的分支之间的微小间隙。

Messages jump across these gaps in the form of molecules⁴ called neurotransmitters.

信息以被称为“神经递质”的分子形式跳过这些缝隙。

Current estimates suggest there are 600 trillion synapses⁵ in a human brain.

根据目前的估计，人类大脑中有600万亿个突触。

How, then, to deal with the stability-plasticity dilemma⁶ - particularly as brains age and, as it were, fill up?

那么，我们该如何平衡大脑的稳定性和可塑性——特别是在大脑老化并且已经“被信息填满”的情况下——我们该如何应对这种两难境地？

Research by Dimitra Vardalaki, Kwanghun Chung and Mark Harnett at the Massachusetts Institute of Technology, just published in Nature, suggests one way is to preserve into adulthood⁷ a type of memory-forming synapse found in children.

麻省理工学院的迪米特拉·瓦达拉基、钟光勋和马克·哈内特的研究表明，一种方法是将儿童大脑中发现的一种形成记忆的突触保留到成年时期。

These are called silent synapses.

这些被保留下来的突触名为沉默突触。

Silent synapses - which, as their name suggests, transmit no signal from one nerve cell to another - are often found on the ends of slender, immature⁸ protrusions from nerve cells, called filopodia.

沉默突触——顾名思义，它不会将信号从一个神经细胞传递到另一个神经细胞——通常出现在神经细胞细长的未成熟突起的末端，称为树突丝。

Until now, it had been thought that these disappeared as a brain matured.

到目前为止，人们一直认为，这些东西会随着大脑的成熟消失。

But Drs Vardalaki, Chung and Harnett have shown not only that they are present in adulthood, but also that they are common, at least in mice.

但瓦达拉基、钟光勋和哈内特博士已经证明，它们不仅能够存在于成年期的大脑中，而且十分常见，至少在老鼠身上是这样。

Just over a quarter of the connections they sampled in adult mouse visual cortices were silent synapses on filopodia.

他们在成年小鼠的视皮层中采样的突触中，略多于四分之一是树突丝上的沉默突触。

And murine and human brains are sufficiently⁹ alike that something similar almost certainly applies to people.

老鼠大脑和人类大脑非常相似，因此几乎可以肯定类似的东西也存在于人类大脑之中。

1 flexibility   

n.柔韧性，弹性，（光的）折射性，灵活性

参考例句：

• Her great strength lies in her flexibility.她的优势在于她灵活变通。
• The flexibility of a man's muscles will lessen as he becomes old.人老了肌肉的柔韧性将降低。

2 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。

3 synapse   

n.突触

参考例句：

• The chemical floods the synapse, overwhelming the serotonin receptors.这种化学物质湮没了突触，覆盖了5--羟色胺的受体。
• Ecstasy also keeps serotonin from being reabsorbed,further increasing the concentration in the synapse.毒品引起的狂迷还能阻止5--羟色胺的再吸收，进一步增加了突触内5--羟色胺的浓度。

4 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

5 synapses   

n.（神经元的）突触( synapse的名词复数 )；染色体结合( synapsis的名词复数 )；联会；突触；（神经元的）触处

参考例句：

• Nerve cells communicate with one another at the synapses, where their membranes almost touch. 神经细胞在突触部位彼此沟通，在这里它们的膜几乎接触到一起了。 来自辞典例句
• Glutamatergic synapses are common excitatory chemical connections in mammalian central nervous system. 谷氨酸性突触是哺乳动物神经系统的主要兴奋性突触。 来自互联网

6 dilemma   

n.困境，进退两难的局面

参考例句：

• I am on the horns of a dilemma about the matter.这件事使我进退两难。
• He was thrown into a dilemma.他陷入困境。

7 adulthood   

n.成年，成人期

参考例句：

• Some infantile actions survive into adulthood.某些婴儿期的行为一直保持到成年期。
• Few people nowadays are able to maintain friendships into adulthood.如今很少有人能将友谊维持到成年。

8 immature   

adj.未成熟的，发育未全的，未充分发展的

参考例句：

• Tony seemed very shallow and immature.托尼看起来好像很肤浅，不夠成熟。
• The birds were in immature plumage.这些鸟儿羽翅未全。

9 sufficiently   

adv.足够地，充分地

参考例句：

• It turned out he had not insured the house sufficiently.原来他没有给房屋投足保险。
• The new policy was sufficiently elastic to accommodate both views.新政策充分灵活地适用两种观点。