科学家可以看到我们睡觉时大脑是如何记录我们的记忆的
Scientists have long known our brains need sleep to review the day's events and transfer them into longer-term memories. Students are often told to study just before turning in to maximize their recall of material for a test the next day.
科学家们早就知道，我们的大脑需要睡眠来回顾当天发生的事情，并将其转化为更长期的记忆。学生们经常被要求在上床睡觉前学习，以便最大限度地回忆第二天考试的内容。
But the exact way in which the brain stores our memories is poorly understood.
但是我们对大脑储存记忆的确切方式知之甚少。
Now for the first time, tiny microelectrodes planted inside the brains of two people with epilepsy show just how the brain's neurons fire during sleep to "replay" our short-term memories in order to move them into more permanent storage. The study was published Tuesday in the journal Cell Reports.
现在，在两名癫痫患者的大脑中植入的微型电极首次显示了大脑神经元如何在睡眠中激活，以“回放”我们的短期记忆，从而将它们转移到更永久的存储器中。这项研究发表在周二的《细胞报告》杂志上。
"This study is fascinating," said Dr. Richard Isaacson, who directs the Alzheimer's Prevention Clinic at Weill Cornell Medicine and New York-Presbyterian Hospital.
“这项研究很有意思，”理查德·艾萨克森博士说。他是威尔·康奈尔医学院和纽约长老会医院老年痴呆症预防诊所的负责人。
"Despite decades of research, it remains somewhat unclear how 'short-term' memories get filed away to become 'long-term' memories that can be recalled later," Isaacson, who was not involved in the study, said.
“尽管进行了几十年的研究，但目前仍不清楚‘短期’记忆是如何被归档，变成‘长期’记忆，以便日后回忆的，”艾萨克森说，他没有参与这项研究。
"Using a brain-computer interface is an exciting way to study memory since it can record brain cell activity patterns and then look for those exact patterns later," he added.
“使用脑-机接口是研究记忆的一种令人兴奋的方式，因为它可以记录脑细胞的活动模式，然后在以后寻找那些确切的模式，”他补充说。
Tracking individual neurons
跟踪单个神经元
The study was conducted at BrainGate, an academic research consortium composed of Brown University, Stanford University and Case Western Reserve University.
这项研究是由布朗大学、斯坦福大学和凯斯西储大学组成的学术研究机构BrainGate进行的。
Braingate has spent the last dozen or more years developing brain-computer interfaces that allow people with amyotrophic lateral sclerosis (ALS) and other neurologic diseases, brain injury or limb loss to be able to use their brain signals to move computer cursors, robotic arms and other assistive devices to communicate and control their world.
在过去的十几年里，Braingate一直在开发脑-机接口，使肌萎缩性侧索硬化症(ALS)和其他神经疾病、脑损伤或肢体丧失的患者能够使用他们的脑信号移动计算机光标、机械臂和其他辅助设备来交流和控制他们的世界。
"Neurons are tiny. They're about 10 microns in size," said computational neuroscientist and study author Beata Jarosiewicz. "And the macro electrodes that are approved for human use, such as the deep brain-stimulating electrodes, are too big to record the individual spiking activity of each neuron."
“神经元是微小的。它们大约只有10微米大小，”计算神经学家和研究作者比塔·贾罗西维奇说。“而那些被批准用于人类的微距电极，比如深度刺激大脑的电极，因为太大而无法记录每个神经元的单个峰值活动。”
But at Braingate, surgeons implanted an array of minute electrodes onto the top of the brains of two people with sensory and motor paralysis, thus allowing the person to just "think" about moving their hand in a direction. By mapping the way the neurons behave during thought, the decoder can translate the thought into speech or into action via attached prosthetic limbs and assistive robotic devices.
但在Braingate，外科医生们在两名感觉和运动瘫痪的患者的大脑顶部植入了一系列微小的电极，从而使患者能够“思考”将手往某个方向移动。通过映射神经元在思维过程中的行为方式，解码器可以通过附加的假肢和辅助机器人装置将思维转化为语言或行动。
"Different neurons have different preferred directions," said Jarosiewicz, who was a research assistant professor at BrainGate at the time of the study.
“不同的神经元有不同的偏好方向，”研究时担任BrainGate研究助理教授的詹若斯维兹说。
There are some at-home monitoring devices, Isaacson said, such as wrist-worn straps and rings, which claim to track different sleep stages that may be most important for memory consolidation.
艾萨克森说，有一些家用监控设备，比如戴在手腕上的肩带和戒指，可以追踪不同的睡眠阶段，而这些阶段对记忆的巩固可能是最重要的。
Hopefully, he said, "future studies will help clarify which specific stages of sleep -- deep sleep, REM sleep -- in which memory replay occurs most frequently."
他说，希望未来的研究能帮助我们弄清楚睡眠的哪些特定阶段——深度睡眠和快速眼动睡眠，在这些阶段中，记忆重现的频率最高。
