Contrast-dependence of surround suppression in Macaque V1: experimental testing of a recurrent network model.
Contrast-dependence of surround suppression in Macaque V1: experimental testing of a recurrent network model.
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DOI：
10.1016/j.neuroimage.2010.01.032
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发表时间：
2010-09
期刊：
影响因子：
5.7
通讯作者：
Angelucci, Alessandra
中科院分区：
文献类型：
--
作者：
Schwabe, Lars;Ichida, Jennifer M.;Shushruth, S.;Mangapathy, Pradeep;Angelucci, Alessandra
初级视皮层（V1）对最佳定向的神经元反应 感受野（RF）中心的高对比度刺激被抑制， 在RF周围的刺激，但可以促进当RF中心是 在低对比度下刺激。周围环境的神经回路和机制 调制仍然是未知的。我们之前提出自上而下的反馈 连接调解来自“远”环境的抑制，而 “近”环绕声抑制主要由水平 连接.我们在V1的递归网络模型中实现了这个想法。一 模型假设需要考虑周围的对比度依赖性信号 调制是兴奋和抑制之间的反应不对称; 因此，抑制，而不是兴奋，是沉默的弱视觉输入， RF中心和周围刺激可以诱发易化。预测 源于这个相同的假设的是，环绕声抑制对于 低于RF中心的高对比度刺激。既往研究 与这一预测不一致。使用猕猴V1的单个单位记录， 我们证实了这个模型的预测。模型模拟表明， 结果可以与以前的研究结果相一致。我们还进行了 实验测量的环绕声抑制的系统比较 强度与预测的模型在不同的参数制度。 我们发现，原来的模型，具有强水平和无反馈 局部抑制性神经元的兴奋，只能部分解释 定量地用于实验测量的抑制。强直接 V1抑制神经元的反馈兴奋是必要的，以解释 实验测量的环绕声抑制强度。
Neuronal responses in primary visual cortex (V1) to optimally oriented high-contrast stimuli in the receptive field (RF) center are suppressed by stimuli in the RF surround, but can be facilitated when the RF center is stimulated at low contrast. The neural circuits and mechanisms for surround modulation are still unknown. We previously proposed that topdown feedback connections mediate suppression from the “far” surround, while “near” surround suppression is mediated primarily by horizontal connections. We implemented this idea in a recurrent network model of V1. A model assumption needed to account for the contrast-dependent sign of surround modulation is a response asymmetry between excitation and inhibition; accordingly, inhibition, but not excitation, is silent for weak visual inputs to the RF center, and surround stimulation can evoke facilitation. A prediction stemming from this same assumption is that surround suppression is weaker for low than for high contrast stimuli in the RF center. Previous studies are inconsistent with this prediction. Using single unit recordings in macaque V1, we confirm this model's prediction. Model simulations demonstrate that our results can be reconciled with those from previous studies. We also performed a systematic comparison of the experimentally-measured surround suppression strength with predictions of the model operated in different parameter regimes. We find that the original model, with strong horizontal and no feedback excitation of local inhibitory neurons, can only partially account quantitatively for the experimentally-measured suppression. Strong direct feedback excitation of V1 inhibitory neurons is necessary to account for the experimentally-measured surround suppression strength.
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