Instituto de Neurociencias de Alicante UMH-CSIC, Avda. Ramón y Cajal s/n, Campus de San Juan, 03550 Sant Joan d'Alacant, Spain.
Laboratory of Neural Computation, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy.
Cereb Cortex. 2017 Jul 1;27(7):3782-3789. doi: 10.1093/cercor/bhx019.
Neurons in the primary sensory regions of neocortex have heterogeneous response properties. The spatial arrangement of neurons with particular response properties is a key aspect of population representations and can shed light on how local circuits are wired. Here, we investigated how neurons with sensitivity to different kinematic features of whisker stimuli are distributed across local circuits in supragranular layers of the barrel cortex. Using 2-photon calcium population imaging in anesthetized mice, we found that nearby neurons represent diverse kinematic features, providing a rich population representation at the local scale. Neurons interspersed in space therefore responded differently to a common stimulus kinematic feature. Conversely, neurons with similar feature selectivity were located no closer to each other than predicted by a random distribution null hypothesis. This finding relied on defining a null hypothesis that was specific for testing the spatial distribution of tuning across neurons. We also measured how neurons sensitive to specific features were distributed relative to barrel boundaries, and found no systematic organization. Our results are compatible with randomly distributed selectivity to kinematic features, with no systematic ordering superimposed upon the whisker map.
新皮层初级感觉区的神经元具有异质性的反应特性。具有特定反应特性的神经元的空间排列是群体表现的一个关键方面，可以揭示局部回路是如何布线的。在这里，我们研究了对胡须刺激的不同运动特征敏感的神经元在桶状皮层的颗粒上层中的局部回路中的分布情况。在麻醉小鼠中使用双光子钙群体成像，我们发现附近的神经元代表了不同的运动特征，在局部尺度上提供了丰富的群体表现。因此，空间上交错的神经元对共同的运动特征刺激有不同的反应。相反，具有相似特征选择性的神经元彼此之间的距离并不比随机分布的零假设预测的更近。这一发现依赖于定义一个零假设，该假设专门用于测试神经元之间调谐的空间分布。我们还测量了对特定特征敏感的神经元相对于桶状皮层边界的分布情况，没有发现系统的组织。我们的结果与运动特征的随机分布选择性兼容，没有叠加在胡须图上的系统排序。
