Systems Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, USA.
Neurosciences Graduate Program, University of California, San Diego, La Jolla, California, USA.
J Comp Neurol. 2022 Dec;530(18):3226-3247. doi: 10.1002/cne.25404. Epub 2022 Sep 7.
The mouse visual system consists of several visual cortical areas thought to be specialized for different visual features and/or tasks. Previous studies have revealed differences between primary visual cortex (V1) and other higher visual areas, namely, anterolateral (AL) and posteromedial (PM), and their tuning preferences for spatial and temporal frequency. However, these differences have primarily been characterized using methods that are biased toward superficial layers of cortex, such as two-photon calcium imaging. Fewer studies have investigated cell types in deeper layers of these areas and their tuning preferences. Because superficial versus deep-layer neurons and different types of deep-layer neurons are known to have different feedforward and feedback inputs and outputs, comparing the tuning preferences of these groups is important for understanding cortical visual information processing. In this study, we used extracellular electrophysiology and two-photon calcium imaging targeted toward two different layer 5 cell classes to characterize their tuning properties in V1, AL, and PM. We find that deep-layer neurons, similar to superficial layer neurons, are also specialized for different spatial and temporal frequencies, with the strongest differences between AL and V1, and AL and PM, but not V1 and PM. However, we note that the deep-layer neuron populations preferred a larger range of SFs and TFs compared to previous studies. We also find that extratelencephalically projecting layer 5 neurons are more direction selective than intratelencephalically projecting layer 5 neurons.
小鼠视觉系统包含几个被认为专门用于不同视觉特征和/或任务的视觉皮层区域。以前的研究揭示了初级视觉皮层（V1）和其他更高的视觉区域（即前外侧（AL）和后内侧（PM））之间的差异，以及它们对空间和时间频率的调谐偏好。然而，这些差异主要是使用偏向于皮质浅层的方法来描述的，例如双光子钙成像。较少的研究调查了这些区域更深层的细胞类型及其调谐偏好。由于浅层与深层神经元以及不同类型的深层神经元已知具有不同的前馈和反馈输入和输出，因此比较这些群体的调谐偏好对于理解皮质视觉信息处理很重要。在这项研究中，我们使用了针对两个不同的第 5 层细胞类别的细胞外电生理学和双光子钙成像，以描述它们在 V1、AL 和 PM 中的调谐特性。我们发现，深层神经元与浅层神经元一样，也专门用于不同的空间和时间频率，AL 和 V1 之间、AL 和 PM 之间的差异最大，但 V1 和 PM 之间没有差异。然而，我们注意到，与以前的研究相比，深层神经元群体更喜欢更大范围的 SFs 和 TFs。我们还发现，向外投射的第 5 层神经元比向脑内投射的第 5 层神经元具有更强的方向选择性。
