Kilpatrick Zachary P, Bard Ermentrout G
Department of Mathematics, University of Pittsburgh, Pittsburgh, PA 15260, USA.
J Comput Neurosci. 2012 Feb;32(1):25-53. doi: 10.1007/s10827-011-0335-y. Epub 2011 Jun 14.
We study the spatiotemporal dynamics of neuronal networks with spike frequency adaptation. In particular, we compare the effects of adaptation being either a linear or nonlinear function of neural activity. We find that altering parameters controlling the strength of synaptic connections in the network can lead to spatially structured activity suggestive of symptoms of hallucinogen persisting perception disorder (HPPD). First, we study how both networks track spatially homogeneous flickering stimuli, and find input is encoded as continuous at lower flicker frequencies when the network's synapses exhibit more net excitation. Mainly, we study instabilities of stimulus-driven traveling pulse solutions, representative of visual trailing phenomena common to HPPD patients. Visual trails are reported as discrete afterimages in the wake of a moving input. Thus, we analyze several solutions arising in response to moving inputs in both networks: an ON state, stimulus-locked pulses, and traveling breathers. We find traveling breathers can arise in both networks when an input moves beyond a critical speed. These possible neural substrates of visual trails occur at slower speeds when the modulation of synaptic connectivity is increased.
我们研究具有脉冲频率适应性的神经网络的时空动态。特别地，我们比较适应性作为神经活动的线性或非线性函数的影响。我们发现，改变控制网络中突触连接强度的参数可导致暗示致幻剂持续性感知障碍（HPPD）症状的空间结构化活动。首先，我们研究两个网络如何跟踪空间均匀的闪烁刺激，并发现当网络的突触表现出更多净兴奋时，输入在较低闪烁频率下被编码为连续的。主要地，我们研究刺激驱动的行波脉冲解的不稳定性，其代表了HPPD患者常见的视觉拖尾现象。视觉拖尾在移动输入之后被报告为离散的后像。因此，我们分析了两个网络中响应移动输入而出现的几种解：一个开启状态、刺激锁定脉冲和行波呼吸子。我们发现当输入移动超过临界速度时，两个网络中都可能出现行波呼吸子。当突触连接性的调制增加时，这些视觉拖尾的可能神经基质以较慢的速度出现。
