Department of Neurobiology, Stanford University, Stanford, California 94305, USA.
J Neurosci. 2011 Apr 6;31(14):5186-96. doi: 10.1523/JNEUROSCI.4592-10.2011.
Essential to the selection of the next target for gaze or attention is the ability to compare the strengths of multiple competing stimuli (bottom-up information) and to signal the strongest one. Although the optic tectum (OT) has been causally implicated in stimulus selection, how it computes the strongest stimulus is unknown. Here, we demonstrate that OT neurons in the barn owl systematically encode the relative strengths of simultaneously occurring stimuli independently of sensory modality. Moreover, special "switch-like" responses of a subset of neurons abruptly increase when the stimulus inside their receptive field becomes the strongest one. Such responses are not predicted by responses to single stimuli and, indeed, are eliminated in the absence of competitive interactions. We demonstrate that this sensory transformation substantially boosts the representation of the strongest stimulus by creating a binary discrimination signal, thereby setting the stage for potential winner-take-all target selection for gaze and attention.
选择下一个注视或注意目标的关键是比较多个竞争刺激（自下而上的信息）的强度并发出最强信号的能力。尽管视顶盖（OT）已被因果关系证明与刺激选择有关，但它如何计算最强刺激尚不清楚。在这里，我们证明了仓鸮的 OT 神经元系统地独立于感觉模态编码同时发生的刺激的相对强度。此外，当感受野内的刺激成为最强刺激时，亚组神经元的特殊“开关样”反应会突然增加。这种反应不能根据单个刺激的反应来预测，实际上，如果没有竞争相互作用，这种反应就会被消除。我们证明，这种感觉转换通过创建二进制判别信号，极大地增强了最强刺激的表示，从而为注视和注意力的潜在胜者通吃目标选择奠定了基础。
