Department of Mathematical Sciences, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA.
J Neurophysiol. 2010 May;103(5):2707-16. doi: 10.1152/jn.00724.2009. Epub 2010 Feb 24.
Synchronous oscillatory dynamics in the beta frequency band is a characteristic feature of neuronal activity of basal ganglia in Parkinson's disease and is hypothesized to be related to the disease's hypokinetic symptoms. This study explores the temporal structure of this synchronization during episodes of oscillatory beta-band activity. Phase synchronization (phase locking) between extracellular units and local field potentials (LFPs) from the subthalamic nucleus (STN) of parkinsonian patients is analyzed here at a high temporal resolution. We use methods of nonlinear dynamics theory to construct first-return maps for the phases of oscillations and quantify their dynamics. Synchronous episodes are interrupted by less synchronous episodes in an irregular yet structured manner. We estimate probabilities for different kinds of these "desynchronization events." There is a dominance of relatively frequent yet very brief desynchronization events with the most likely desynchronization lasting for about one cycle of oscillations. The chances of longer desynchronization events decrease with their duration. The observed synchronization may primarily reflect the relationship between synaptic input to STN and somatic/axonal output from STN at rest. The intermittent, transient character of synchrony even on very short time scales may reflect the possibility for the basal ganglia to carry out some informational function even in the parkinsonian state. The dominance of short desynchronization events suggests that even though the synchronization in parkinsonian basal ganglia is fragile enough to be frequently destabilized, it has the ability to reestablish itself very quickly.
同步振荡动力学在β频带是基底神经节神经元活动的特征帕金森病并假设与疾病的运动徐缓症状有关。本研究探讨了这种同步的时间结构在振荡β频带活动期间的事件。相位同步（锁相）在帕金森病患者的丘脑底核（STN）的细胞外单元和局部场电位（LFP）之间在此以高时间分辨率进行分析。我们使用非线性动力学理论的方法来构建振荡相位的第一返回图，并量化它们的动力学。同步事件以不规则但有结构的方式被不那么同步的事件中断。我们估计这些“去同步事件”的不同类型的概率。存在相对频繁但非常短暂的去同步事件的主导地位，最有可能的去同步持续约一个振荡周期。随着持续时间的延长，较长去同步事件的可能性会降低。观察到的同步可能主要反映了 STN 的突触输入与 STN 的体/轴突输出之间的关系在休息时。即使在非常短的时间尺度上，同步的间歇性和瞬态特征也可能反映了基底神经节即使在帕金森状态下也具有执行某些信息功能的可能性。短去同步事件的主导地位表明，尽管帕金森病基底神经节中的同步性脆弱到足以经常失稳，但它具有非常快速重建自身的能力。
