Shapley Robert, Hawken Michael, Ringach Dario L
Center for Neural Science, New York University, New York, NY 10003, USA.
Neuron. 2003 Jun 5;38(5):689-99. doi: 10.1016/s0896-6273(03)00332-5.
To test theories of orientation selectivity in primary visual cortex (V1), we have done experiments to measure the dynamics of orientation tuning of single neurons in the V1 cortex of macaque monkeys. Based on our dynamics results, we propose that a V1 cell's orientation selectivity is generated mainly by both tuned enhancement and global suppression. Enhancement near the preferred orientation is probably caused by feed-forward input from LGN (plus amplification by cortical-cortical interaction). Global suppression could be supplied by cortical inhibition. Additionally, in about 1/3 of V1 neurons (usually the most sharply tuned) there is tuned suppression, centered near the cell's preferred orientation but broader than tuned enhancement. These mechanisms also can explain important features of steady-state selectivity in the V1 neuron population. Furthermore, similar neuronal mechanisms may be used generally throughout the cerebral cortex.
为了检验初级视觉皮层（V1）中方向选择性的理论，我们进行了实验，以测量猕猴V1皮层中单个神经元方向调谐的动力学。基于我们的动力学结果，我们提出V1细胞的方向选择性主要由调谐增强和全局抑制共同产生。偏好方向附近的增强可能是由外侧膝状体的前馈输入（加上皮层-皮层相互作用的放大）引起的。全局抑制可能由皮层抑制提供。此外，在大约1/3的V1神经元中（通常是调谐最尖锐的）存在调谐抑制，其中心在细胞的偏好方向附近，但比调谐增强更宽。这些机制也可以解释V1神经元群体中稳态选择性的重要特征。此外，类似的神经元机制可能在整个大脑皮层中普遍使用。
