Pascarella Annalisa, Gianni Eugenia, Abbondanza Matteo, Armonaite Karolina, Pitolli Francesca, Bertoli Massimo, L'Abbate Teresa, Grifoni Joy, Vitulano Domenico, Bruni Vittoria, Conti Livio, Paulon Luca, Tecchio Franca
Institute for the Applications of Calculus "M. Picone", National Research Council, Rome, Italy.
Laboratory of Electrophysiology for Translational NeuroScience, Institute of Cognitive Sciences and Technologies, Consiglio Nazionale delle Ricerche, Rome, Italy.
Front Neurosci. 2022 Nov 10;16:933391. doi: 10.3389/fnins.2022.933391. eCollection 2022.
The neuronal functional connectivity is a complex and non-stationary phenomenon creating dynamic networks synchronization determining the brain states and needed to produce tasks. Here, as a measure that quantifies the synchronization between the neuronal electrical activity of two brain regions, we used the normalized compression distance (NCD), which is the length of the compressed file constituted by the concatenated two signals, normalized by the length of the two compressed files including each single signal. To test the NCD sensitivity to physiological properties, we used NCD to measure the cortico-muscular synchronization, a well-known mechanism to control movements, in 15 healthy volunteers during a weak handgrip. Independently of NCD compressor (Huffman or Lempel Ziv), we found out that the resulting measure is sensitive to the dominant-non dominant asymmetry when novelty management is required ( = 0.011; = 0.007, respectively) and depends on the level of novelty when moving the non-dominant hand ( = 0.012; = 0.024). Showing lower synchronization levels for less dexterous networks, NCD seems to be a measure able to enrich the estimate of functional two-node connectivity within the neuronal networks that control the body.
神经元功能连接是一种复杂且非平稳的现象，它会产生动态网络同步，从而决定大脑状态并完成各种任务。在此，作为一种量化两个脑区神经元电活动之间同步性的指标，我们使用了归一化压缩距离（NCD），它是由两个信号连接而成的压缩文件的长度，再通过包含每个单一信号的两个压缩文件的长度进行归一化处理。为了测试NCD对生理特性的敏感性，我们让15名健康志愿者在进行轻微握力动作时，使用NCD来测量皮质 - 肌肉同步性，这是一种控制运动的著名机制。无论使用哪种NCD压缩器（哈夫曼或莱姆佩尔 - 齐夫），我们都发现，当需要进行新颖性管理时（分别为 = 0.011； = 0.007），所得指标对优势 - 非优势不对称敏感，并且在移动非优势手时取决于新颖性水平（ = 0.012； = 0.024）。NCD显示出在灵活性较低的网络中同步水平较低，它似乎是一种能够丰富对控制身体的神经元网络内功能双节点连接估计的指标。
