Parallel pathways for representing temporal sensory information

啮齿动物是夜间活动的，很大程度上依靠它们的胡须来感知环境的精确性质，该系统的分辨率令人印象深刻：使用它的胡须，一只蒙着眼睛的老鼠可以区分只有微米级表面纹理差异的物体。由于众所周知，不同哺乳动物的不同感觉系统有深刻的相似之处，研究老鼠的胡须可以为了解大脑中感觉机制的一般问题提供重要的见解。当老鼠探索一个物体时，它会以大约每秒10次的速度在物体表面来回扫胡须。这会导致胡须振动。这些振动被称为“微动”，它们很重要，因为正是因为不同的物体会引起不同的微动，老鼠才能区分它们。一个关键的含义是，大鼠大脑中神经元的一个关键功能是代表和处理胡须运动。但这是如何发生的，目前还没有完全弄清楚。在我的实验室里，我们最近在理解丘脑--所有感官的重要控制中心--如何代表胡须运动方面取得了进展。以前人们认为丘脑中的神经元对胡须刺激的反应是相同的，但我们出人意料地发现了多样性。这一新发现带来了许多新的问题，包括：这种多样性在大脑中起源于哪里？不同类型的神经元是否位于丘脑的不同部位？大脑皮层中有相应类型的神经元吗？大脑皮层是大脑的关键结构，是大脑感觉回路中仅次于丘脑的下一层。在这个项目中，我们试图回答这些问题。这项研究的更广泛的意义在于，它将为感官系统和感官信息的处理提供新的见解。

Being nocturnal, rodents rely to a large extent on their whiskers to sense the precise nature of the environment, and the resolution of the system is impressive: using its whiskers, a blind-folded rat can discriminate between objects that differ only in micron-scale surface texture. Since it is well-established that different sensory systems in different mammals have profound similarities, studying the rats whiskers can offer important insight into general questions about the mechanisms of sensation in the brain. When a rat is exploring an object, it sweeps its whiskers back and forth across the surface around 10 times per second. This causes the whiskers to vibrate. These vibrations are known as 'micromotions' and they are important, since it is because different objects evoke different micromotions that the rat is able to tell them apart. A key implication is that a critical function of neurons in the rat's brain is to represent and process whisker motion. But how this happens is not fully understood. In my laboratory, we have recently made progress in understanding how the thalamus - a vital control centre for all the senses - represents whisker motion. Whereas previously it was thought that neurons in the thalamus all respond in the same way to a whisker stimulus, we unexpectedly found diversity. This new discovery opens up many new questions, including: Where in the brain does this diversity originate? Are neurons of different types located in different parts of the thalamus? Are there corresponding types of neuron in the cerebral cortex - a key brain structure, which is the next level after the thalamus in the brain's sensory circuit. In this project, we seek to answer these questions. The wider significance of the research is that it will contribute new insight into sensory systems and how sensory information is processed.