Tomková Markéta, Tomek Jakub, Novák Ondřej, Zelenka Ondřej, Syka Josef, Brom Cyril
Faculty of Mathematics and Physics, Charles University in Prague, Prague, Czech Republic.
Life Sciences Interface Doctoral Training Centre, University of Oxford, Oxford, UK.
J Comput Neurosci. 2015 Oct;39(2):131-53. doi: 10.1007/s10827-015-0568-2. Epub 2015 Sep 7.
There is ample experimental evidence describing changes of tonotopic organisation in the auditory cortex due to environmental factors. In order to uncover the underlying mechanisms, we designed a large-scale computational model of the auditory cortex. The model has up to 100 000 Izhikevich's spiking neurons of 17 different types, almost 21 million synapses, which are evolved according to Spike-Timing-Dependent Plasticity (STDP) and have an architecture akin to existing observations. Validation of the model revealed alternating synchronised/desynchronised states and different modes of oscillatory activity. We provide insight into these phenomena via analysing the activity of neuronal subtypes and testing different causal interventions into the simulation. Our model is able to produce experimental predictions on a cell type basis. To study the influence of environmental factors on the tonotopy, different types of auditory stimulations during the evolution of the network were modelled and compared. We found that strong white noise resulted in completely disrupted tonotopy, which is consistent with in vivo experimental observations. Stimulation with pure tones or spontaneous activity led to a similar degree of tonotopy as in the initial state of the network. Interestingly, weak white noise led to a substantial increase in tonotopy. As the STDP was the only mechanism of plasticity in our model, our results suggest that STDP is a sufficient condition for the emergence and disruption of tonotopy under various types of stimuli. The presented large-scale model of the auditory cortex and the core simulator, SUSNOIMAC, have been made publicly available.
有大量实验证据描述了由于环境因素导致听觉皮层中音调组织的变化。为了揭示其潜在机制，我们设计了一个大规模的听觉皮层计算模型。该模型有多达10万个17种不同类型的艾克维克脉冲神经元、近2100万个突触，这些突触根据依赖于脉冲时间的可塑性（STDP）进行演化，并且具有类似于现有观察结果的结构。对该模型的验证揭示了交替的同步/去同步状态以及不同的振荡活动模式。我们通过分析神经元亚型的活动并在模拟中测试不同的因果干预来深入了解这些现象。我们的模型能够在细胞类型的基础上做出实验预测。为了研究环境因素对音调拓扑的影响，我们对网络演化过程中不同类型的听觉刺激进行了建模和比较。我们发现强烈的白噪声会导致音调拓扑完全被破坏，这与体内实验观察结果一致。纯音刺激或自发活动导致的音调拓扑程度与网络初始状态相似。有趣的是，弱白噪声会导致音调拓扑大幅增加。由于STDP是我们模型中唯一的可塑性机制，我们的结果表明STDP是在各种类型刺激下音调拓扑出现和破坏的充分条件。所展示的大规模听觉皮层模型和核心模拟器SUSNOIMAC已公开可用。
