Körding Konrad P, Kayser Christoph, Einhäuser Wolfgang, König Peter
Institute of Neurology, University College London, London, WC1N 3BG, United Kingdom.
J Neurophysiol. 2004 Jan;91(1):206-12. doi: 10.1152/jn.00149.2003. Epub 2003 Aug 6.
Sensory areas should be adapted to the properties of their natural stimuli. What are the underlying rules that match the properties of complex cells in primary visual cortex to their natural stimuli? To address this issue, we sampled movies from a camera carried by a freely moving cat, capturing the dynamics of image motion as the animal explores an outdoor environment. We use these movie sequences as input to simulated neurons. Following the intuition that many meaningful high-level variables, e.g., identities of visible objects, do not change rapidly in natural visual stimuli, we adapt the neurons to exhibit firing rates that are stable over time. We find that simulated neurons, which have optimally stable activity, display many properties that are observed for cortical complex cells. Their response is invariant with respect to stimulus translation and reversal of contrast polarity. Furthermore, spatial frequency selectivity and the aspect ratio of the receptive field quantitatively match the experimentally observed characteristics of complex cells. Hence, the population of complex cells in the primary visual cortex can be described as forming an optimally stable representation of natural stimuli.
感觉区域应适应其天然刺激的特性。将初级视觉皮层中复杂细胞的特性与其天然刺激相匹配的潜在规则是什么？为了解决这个问题，我们从一只自由移动的猫所携带的相机中采样视频，捕捉动物探索户外环境时图像运动的动态。我们将这些视频序列用作模拟神经元的输入。基于许多有意义的高级变量（例如可见物体的身份）在自然视觉刺激中不会快速变化的直觉，我们使神经元适应以表现出随时间稳定的放电率。我们发现，具有最佳稳定活动的模拟神经元表现出许多在皮层复杂细胞中观察到的特性。它们的反应对于刺激平移和对比度极性反转是不变的。此外，空间频率选择性和感受野的纵横比在数量上与实验观察到的复杂细胞特征相匹配。因此，初级视觉皮层中的复杂细胞群体可以被描述为形成了天然刺激的最佳稳定表征。
