Spectral receptive field properties explain shape selectivity in area V4
Spectral receptive field properties explain shape selectivity in area V4
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DOI：
10.1152/jn.00575.2006
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发表时间：
2006-12-01
影响因子：
2.5
通讯作者：
Gallant, Jack L.
中科院分区：
文献类型：
--
作者：
David, Stephen V.;Hayden, Benjamin Y.;Gallant, Jack L.
皮质区 V4 的神经元选择性地响应复杂的视觉模式，例如弯曲轮廓和非笛卡尔光栅。 V4 中的大多数先前实验都测量了对小型特殊刺激集的反应，并且还没有单一的功能模型可以解释所有不同的结果。我们提出一种模型，即光谱感受野 (SRF)，可以解释 V4 中选择性的许多观察结果。 SRF 描述了方向和空间频谱方面的调谐，原则上可以预测对任何视觉刺激的响应。我们通过对大量自然图像的响应的线性化逆相关来估计清醒灵长类动物 V4 中神经元的 SRF。我们发现 V4 神经元具有较大的方向和空间频率带宽，并且通常是双峰方向调整。为了进行比较，我们估计了初级视觉皮层 (V1) 神经元的 SRF。与之前的观察一致，我们发现 V1 神经元的带宽比 V4 更窄。为了确定估计的 SRF 是否可以解释先前对选择性的观察，我们使用它们来预测对笛卡尔光栅、非笛卡尔光栅、自然图像和弯曲轮廓的响应。基于这些预测，我们发现 V1 中的大多数神经元对笛卡尔光栅具有选择性，而 V4 中的大多数神经元对非笛卡尔光栅或自然图像具有选择性。 SRF 使用二阶非线性模型描述视觉调谐特性。这些结果支持二阶模型足以描述的假设
Neurons in cortical area V4 respond selectively to complex visual patterns such as curved contours and non-Cartesian gratings. Most previous experiments in V4 have measured responses to small, idiosyncratic stimulus sets and no single functional model yet accounts for all of the disparate results. We propose that one model, the spectral receptive field (SRF), can explain many observations of selectivity in V4. The SRF describes tuning in terms of the orientation and spatial frequency spectrum and can, in principle, predict the response to any visual stimulus. We estimated SRFs for neurons in V4 of awake primates by linearized reverse correlation of responses to a large set of natural images. We find that V4 neurons have large orientation and spatial frequency bandwidth and often bimodal orientation tuning. For comparison, we estimated SRFs for neurons in primary visual cortex (V1). Consistent with previous observations, we find that V1 neurons have narrower bandwidth than that of V4. To determine whether estimated SRFs can account for previous observations of selectivity, we used them to predict responses to Cartesian gratings, non-Cartesian gratings, natural images, and curved contours. Based on these predictions, we find that the majority of neurons in V1 are selective for Cartesian gratings, whereas the majority of V4 neurons are selective for non-Cartesian gratings or natural images. The SRF describes visual tuning properties with a second-order nonlinear model. These results support the hypothesis that a second-order model is sufficient to describe