Behavioral Physiology Group, Department of Biology, Humboldt-Universität zu Berlin and Bernstein Center for Computational Neuroscience, 10115 Berlin, Germany.
J Neurosci. 2013 Jul 17;33(29):12136-45. doi: 10.1523/JNEUROSCI.0724-13.2013.
Traditionally, perceptual decision making is studied in trained animals and carefully controlled tasks. Here, we sought to elucidate the stimulus features and their combination underlying a naturalistic behavior--female decision making during acoustic courtship in grasshoppers. Using behavioral data, we developed a model in which stimulus features were extracted by physiologically plausible models of sensory neurons from the time-varying stimulus. This sensory evidence was integrated over the stimulus duration and combined to predict the behavior. We show that decisions were determined by the interaction of an excitatory and a suppressive stimulus feature. The observed increase of behavioral response with stimulus intensity was the result of an increase of the excitatory feature's gain that was not controlled by an equivalent increase of the suppressive feature. Differences in how these two features were combined could explain interindividual variability. In addition, the mapping between the two stimulus features and different parameters of the song led us to re-evaluate the cues underlying acoustic communication. Our framework provided a rich and plausible explanation of behavior in terms of two stimulus cues that were extracted by models of sensory neurons and combined through excitatory-inhibitory interactions. We thus were able to link single neuron's feature selectivity and network computations with decision making in a natural task. This data-driven approach has the potential to advance our understanding of decision making in other systems and can inform the search for the neural correlates of behavior.
传统上，感知决策是在经过训练的动物和精心控制的任务中进行研究的。在这里，我们试图阐明自然行为——草地蟋蟀在声学求偶期间的雌性决策——背后的刺激特征及其组合。我们使用行为数据开发了一个模型，其中刺激特征是通过感觉神经元的生理上合理的模型从时变刺激中提取的。这种感觉证据在刺激持续时间内被整合，并结合起来预测行为。我们表明，决策是由兴奋和抑制刺激特征的相互作用决定的。观察到的行为反应随刺激强度的增加而增加，是由于兴奋性特征的增益增加所致，而抑制性特征的增益增加并没有得到控制。这两个特征的组合方式的差异可以解释个体间的可变性。此外，这两个刺激特征与歌曲的不同参数之间的映射关系使我们重新评估了声学通讯的基础线索。我们的框架根据从感觉神经元模型中提取的两个刺激线索，并通过兴奋-抑制相互作用进行组合，为行为提供了丰富而合理的解释。因此，我们能够将单个神经元的特征选择性和网络计算与自然任务中的决策联系起来。这种基于数据的方法有可能促进我们对其他系统中决策的理解，并为寻找行为的神经相关性提供信息。
