Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, London W1T 4JG, UK; Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK.
Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK.
Curr Biol. 2024 Aug 5;34(15):3405-3415.e5. doi: 10.1016/j.cub.2024.06.057. Epub 2024 Jul 19.
A major challenge in neuroscience is to understand how neural representations of sensory information are transformed by the network of ascending and descending connections in each sensory system. By recording from neurons at several levels of the auditory pathway, we show that much of the nonlinear encoding of complex sounds in auditory cortex can be explained by transformations in the midbrain and thalamus. Modeling cortical neurons in terms of their inputs across these subcortical populations enables their responses to be predicted with unprecedented accuracy. By contrast, subcortical responses cannot be predicted from descending cortical inputs, indicating that ascending transformations are irreversible, resulting in increasingly lossy, higher-order representations across the auditory pathway. Rather, auditory cortex selectively modulates the nonlinear aspects of thalamic auditory responses and the functional coupling between subcortical neurons without affecting the linear encoding of sound. These findings reveal the fundamental role of subcortical transformations in shaping cortical responses.
神经科学的一个主要挑战是理解每个感觉系统中上行和下行连接网络如何改变感觉信息的神经表示。通过记录听觉通路上的几个神经元水平的活动，我们发现听觉皮层中复杂声音的大部分非线性编码可以通过中脑和丘脑的转换来解释。根据这些皮质下群体的输入对皮质神经元进行建模，可以以前所未有的精度来预测它们的反应。相比之下，皮质下的反应不能从皮质下的输入来预测，这表明上行转换是不可逆的，导致听觉通路上的表示越来越具有损耗性和更高阶。相反，听觉皮层选择性地调节丘脑听觉反应的非线性方面和皮质下神经元之间的功能耦合，而不影响声音的线性编码。这些发现揭示了皮质下转换在塑造皮质反应中的基本作用。
