Mechanisms of Spatiotemporal Selectivity in Cortical Area MT.
Mechanisms of Spatiotemporal Selectivity in Cortical Area MT.
复制标题
皮质区 MT 时空选择性机制。
DOI：
10.1016/j.neuron.2018.12.002
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发表时间：
2019
期刊：
影响因子：
16.2
通讯作者：
Albright,ThomasD
中科院分区：
文献类型：
--
作者：
Pawar,AmbarishS;Gepshtein,Sergei;Savel'ev,Sergey;Albright,ThomasD
皮质感觉神经元的特征在于对刺激的选择性。这种选择性最初被认为是神经元的基本“感受野”特征的一部分。这一观点后来受到证据的挑战，即感受野是由经典感受野之外的刺激调制的。在这里，我们表明，即使是这种修改后的选择性需要修改。我们测量了警觉猴皮层区MT神经元的空间频率选择性，发现它们的选择性强烈依赖于亮度对比度，随着对比度的增加而向更高的空间频率移动。在时间频率较低时，偏好空间频率的变化较大，随着时间频率的增加，偏好空间频率的变化单调减小。也就是说，甚至亮度对比度，空间频率和时间频率的基本刺激维度之间的相互作用强烈影响神经元的选择性。神经元选择性的这种动态性质与刺激偏好作为皮层神经元的稳定特征的概念不一致。
Cortical sensory neurons are characterized by selectivity to stimulation. This selectivity was originally viewed as a part of the fundamental "receptive field" characteristic of neurons. This view was later challenged by evidence that receptive fields are modulated by stimuli outside of the classical receptive field. Here, we show that even this modified view of selectivity needs revision. We measured spatial frequency selectivity of neurons in cortical area MT of alert monkeys and found that their selectivity strongly depends on luminance contrast, shifting to higher spatial frequencies as contrast increases. The changes of preferred spatial frequency are large at low temporal frequency, and they decrease monotonically as temporal frequency increases. That is, even interactions among basic stimulus dimensions of luminance contrast, spatial frequency, and temporal frequency strongly influence neuronal selectivity. This dynamic nature of neuronal selectivity is inconsistent with the notion of stimulus preference as a stable characteristic of cortical neurons.