Orientation and direction selectivity of neurons in V1 of alert monkeys: Functional relationships and laminar distributions
Orientation and direction selectivity of neurons in V1 of alert monkeys: Functional relationships and laminar distributions
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DOI：
10.1093/cercor/bhi003
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发表时间：
2005-08-01
期刊：
影响因子：
3.7
通讯作者：
Snodderly, DM
中科院分区：
文献类型：
--
作者：
Gur, M;Kagan, I;Snodderly, DM
我们研究了警觉猴V1的方向选择性及其与其他生理参数和解剖组织的关系。单个神经元被刺激与漂移酒吧或正弦光栅，同时补偿眼睛的位置。通过圆方差和方向调谐曲线的带宽来量化基于尖峰计数的方向选择性。圆形方差分布为双峰，表明具有低选择性和高选择性的组。方向选择性明显与自发活动，经典感受野（CRF）的大小和周围抑制的强度。神经元特性的层状分布是不同的。输出层2/3、4 B和5的神经元自发活动低，CRF小，方向选择性高，而输入层的神经元多样性较大。方向选择性细胞是神经元中对方向选择性最强的细胞，大多数具有小的CRF。一个窄带的方向和方向选择性细胞与小CRF位于中间的层4C，表明外观非常选择性的细胞在早期阶段的皮层处理。我们认为，这些结果反映了兴奋和抑制机制之间的相互作用，具体到每个亚板。具有较少抑制的区域具有较高的自发活动、较大的CRF和较宽的定向调谐。在抑制作用较强的地方，自发活动几乎消失，CRF收缩，取向选择性高。
We studied orientation selectivity in V1 of alert monkeys and its relationship to other physiological parameters and to anatomical organization. Single neurons were stimulated with drifting bars or with sinusoidal gratings while compensating for eye position. Orientation selectivity based on spike counts was quantified by circular variance and by the bandwidth of the orientation tuning curve. The circular variance distribution was bimodal, suggesting groups with low and with high selectivity. Orientation selectivity was clearly correlated with spontaneous activity, classical receptive field (CRF) size and the strength of surround suppression. Laminar distributions of neuronal properties were distinct. Neurons in the output layers 2/3, 4B and 5 had low spontaneous activity, small CRFs and high orientation selectivity, while the input layers had greater diversity. Direction-selective cells were among the neurons most selective for orientation and most had small CRFs. A narrow band of direction- and orientation-selective cells with small CRFs was located in the middle of layer 4C, indicating appearance of very selective cells at an early stage of cortical processing. We suggest that these results reflect interactions between excitatory and inhibitory mechanisms specific to each sublamina. Regions with less inhibition have higher spontaneous activity, larger CRFs and broader orientation tuning. Where inhibition is stronger, spontaneous activity almost disappears, CRFs shrink, and orientation selectivity is high.