Center for Neural Science, New York University, New York, NY 10003
Proc Natl Acad Sci U S A. 2019 May 7;116(19):9634-9643. doi: 10.1073/pnas.1900804116. Epub 2019 Apr 22.
The CA3 and dentate gyrus (DG) regions of the hippocampus are considered key for disambiguating sensory inputs from similar experiences in memory, a process termed pattern separation. The neural mechanisms underlying pattern separation, however, have been difficult to compare across species: rodents offer robust recording methods with less human-centric tasks, while humans provide complex behavior with less recording potential. To overcome these limitations, we trained monkeys to perform a visual pattern separation task similar to those used in humans while recording activity from single CA3/DG neurons. We find that, when animals discriminate recently seen novel images from similar (lure) images, behavior indicative of pattern separation, CA3/DG neurons respond to lure images more like novel than repeat images. Using a population of these neurons, we are able to classify novel, lure, and repeat images from each other using this pattern of firing rates. Notably, one subpopulation of these neurons is more responsible for distinguishing lures and repeats-the key discrimination indicative of pattern separation.
海马体的 CA3 和齿状回（DG）区域被认为是将相似经历的感觉输入与记忆中的感觉输入区分开来的关键，这个过程被称为模式分离。然而，跨物种比较模式分离的神经机制一直具有挑战性：啮齿动物提供了强大的记录方法，但任务以人为中心程度较低，而人类提供了复杂的行为，但记录潜力较小。为了克服这些限制，我们训练猴子执行类似于人类的视觉模式分离任务，同时记录单个 CA3/DG 神经元的活动。我们发现，当动物从相似的（诱饵）图像中辨别出最近看到的新图像时，表明模式分离的行为，CA3/DG 神经元对诱饵图像的反应更像新图像而不是重复图像。使用这些神经元的一个群体，我们能够使用这种放电率模式彼此区分新图像、诱饵图像和重复图像。值得注意的是，这些神经元的一个亚群更负责区分诱饵和重复——这是模式分离的关键区别。
