Department of Physics, University of Ottawa, Ottawa, Ontario, Canada.
PLoS Comput Biol. 2013;9(9):e1003180. doi: 10.1371/journal.pcbi.1003180. Epub 2013 Sep 12.
Cancellation of redundant information is a highly desirable feature of sensory systems, since it would potentially lead to a more efficient detection of novel information. However, biologically plausible mechanisms responsible for such selective cancellation, and especially those robust to realistic variations in the intensity of the redundant signals, are mostly unknown. In this work, we study, via in vivo experimental recordings and computational models, the behavior of a cerebellar-like circuit in the weakly electric fish which is known to perform cancellation of redundant stimuli. We experimentally observe contrast invariance in the cancellation of spatially and temporally redundant stimuli in such a system. Our model, which incorporates heterogeneously-delayed feedback, bursting dynamics and burst-induced STDP, is in agreement with our in vivo observations. In addition, the model gives insight on the activity of granule cells and parallel fibers involved in the feedback pathway, and provides a strong prediction on the parallel fiber potentiation time scale. Finally, our model predicts the existence of an optimal learning contrast around 15% contrast levels, which are commonly experienced by interacting fish.
冗余信息的消除是感觉系统的一个非常理想的特性，因为它可能导致对新信息的更有效检测。然而，负责这种选择性消除的生物上合理的机制，特别是那些对冗余信号强度的实际变化具有鲁棒性的机制，在很大程度上是未知的。在这项工作中，我们通过体内实验记录和计算模型研究了弱电鱼中一种类似小脑的电路的行为，该电路已知能够消除冗余刺激。我们在这样的系统中实验观察到空间和时间冗余刺激消除的对比度不变性。我们的模型，它包含异时滞反馈、爆发动力学和爆发诱导的 STDP，与我们的体内观察结果一致。此外，该模型提供了关于参与反馈通路的颗粒细胞和平行纤维的活动的深入了解，并对平行纤维增强的时间尺度做出了强有力的预测。最后，我们的模型预测了在 15%左右的对比度水平下存在最佳的学习对比度，这是相互作用的鱼通常经历的对比度水平。
