Rhythm and Synchrony in a Cortical Network Model
Rhythm and Synchrony in a Cortical Network Model
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DOI：
10.1523/jneurosci.0675-18.2018
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发表时间：
2018-10-03
影响因子：
5.3
通讯作者：
Young, Lai-Sang
中科院分区：
文献类型：
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作者：
Chariker, Logan;Shapley, Robert;Young, Lai-Sang
我们研究了大脑皮层中皮质伽玛带活动的机制，并确定了影响此类活动的神经生物学因素。这是通过分析先前开发的数据驱动的大规模网络模型的行为来完成的，该模型模拟了猴子 VI 皮层的许多视觉功能（Chariker 等人，2016）。伽马活动是该模型的一个新兴属性。该模型的伽玛活动与真实皮层的伽玛活动一样，是（1）情景性的，（2）频率和相位可变的，以及（3）功率随方向等刺激变量分级。在以伽玛速率发生的多次放电事件 (MFE) 期间，模型神经元群的尖峰放电仅部分同步。对模型 MFE 的详细分析表明，伽马能带活动的来源是多维的。大多数尖峰是由兴奋性输入引起的。这些输入的很大一部分来自本地电路内的循环激励，但前馈和反馈激励也做出了贡献，无论是通过直接脉冲还是通过提高整体基线。抑制是 MFE 结束的原因，但去抑制只直接导致一小部分同步峰值。作为对在皮层不同部分观察到的广泛伽马特征的潜在解释，我们发现 AMPA 和 GABA 突触电导的相对上升时间对伽马同步程度有很大影响。
We studied mechanisms for cortical gamma-band activity in the cerebral cortex and identified neurobiological factors that affect such activity. This was done by analyzing the behavior of a previously developed, data-driven, large-scale network model that simulated many visual functions of monkey VI cortex (Chariker et al., 2016). Gamma activity was an emergent property of the model. The model's gamma activity, like that of the real cortex, was (1) episodic, (2) variable in frequency and phase, and (3) graded in power with stimulus variables like orientation. The spike firing of the model's neuronal population was only partially synchronous during multiple firing events (MFEs) that occurred at gamma rates. Detailed analysis of the model's MFEs showed that gamma-band activity was multidimensional in its sources. Most spikes were evoked by excitatory inputs. A large fraction of these inputs came from recurrent excitation within the local circuit, but feedforward and feedback excitation also contributed, either through direct pulsing or by raising the overall baseline. Inhibition was responsible for ending MFEs, but disinhibition led directly to only a small minority of the synchronized spikes. As a potential explanation for the wide range of gamma characteristics observed in different parts of cortex, we found that the relative rise times of AMPA and GABA synaptic conductances have a strong effect on the degree of synchrony in gamma.