Pseudo-plateau bursting and mixed-mode oscillations in a model of developing inner hair cells
Pseudo-plateau bursting and mixed-mode oscillations in a model of developing inner hair cells
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DOI：
10.1016/j.cnsns.2019.104979
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发表时间：
2020-01-01
影响因子：
3.9
通讯作者：
Tsaneva-Atanasova, Krasimira
中科院分区：
文献类型：
--
作者：
Baldemir, Harun;Avitabile, Daniele;Tsaneva-Atanasova, Krasimira
内耳毛细胞（IHCs）是内耳中可兴奋的感觉细胞，负责编码声音信息。在听力发生之前，IHCs发射钙基动作电位，触发递质释放到发育中的螺旋神经节神经元。越来越多的实验证据表明，这些自发放电模式与IHC突触的成熟有关，因此参与了听力的发展。因此，组织ihc电活动的动力学是我们感兴趣的。在我们之前的建模工作的基础上，我们提出了一个三维的，减少的IHC模型，并进行了非量纲化。我们发现，在一个重要的参数值范围内，简化（三维）模型的动态可以很好地映射到原始生物物理（四维）IHC模型中观察到的动态。通过估计简化IHC模型中变量的典型时间尺度，我们证明该模型可以由两个快一个慢或一个快两个慢变量表征，这取决于控制动力学的生物物理相关参数。具体来说，我们研究了电压门控钙通道电导的变化以及模型中与游离胞质钙浓度比例相对应的参数如何影响振荡模型行为，从而从伪平台破裂过渡到混合模式振荡。因此，通过快慢分析，我们能够进一步理解该模型，并通过改变模型中的单个参数，在参数空间中揭示连接伪平台爆发和混合模式振荡的路径。(c) 2019年作者。这是一篇基于CC by许可的开放获取文章。(http://creativecommons.org/licenses/by/4.0/)
Inner hair cells (IHCs) are excitable sensory cells in the inner ear that encode acoustic information. Before the onset of hearing IHCs fire calcium-based action potentials that trigger transmitter release onto developing spiral ganglion neurones. There is accumulating experimental evidence that these spontaneous firing patterns are associated with maturation of the IHC synapses and hence involved in the development of hearing. The dynamics organising the IHCs' electrical activity are therefore of interest.Building on our previous modelling work we propose a three-dimensional, reduced IHC model and carry out non-dimensionalisation. We show that there is a significant range of parameter values for which the dynamics of the reduced (three-dimensional) model map well onto the dynamics observed in the original biophysical (four-dimensional) IHC model. By estimating the typical time scales of the variables in the reduced IHC model we demonstrate that this model could be characterised by two fast and one slow or one fast and two slow variables depending on biophysically relevant parameters that control the dynamics. Specifically, we investigate how changes in the conductance of the voltage-gated calcium channels as well as the parameter corresponding to the fraction of free cytosolic calcium concentration in the model affect the oscillatory model bahaviour leading to transition from pseudo-plateau bursting to mixed-mode oscillations. Hence, using fast-slow analysis we are able to further our understanding of this model and reveal a path in the parameter space connecting pseudo-plateau bursting and mixed-mode oscillations by varying a single parameter in the model. (c) 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license. (http://creativecommons.org/licenses/by/4.0/)