Erbil N, Yagcioglu Suha
Funct Neurol. 2016 Oct/Dec;31(4):249-256. doi: 10.11138/fneur/2016.31.4.249.
The Poffenberger paradigm is a well-known measure of interhemispheric transfer delays, calculated on the basis of the crossed vs uncrossed reaction time difference (CUD). However, the proper interpretation of CUD is extensively debated in the literature. In this study we used connectivity measures in an attempt to interpret CUD from the perspective of functional connectivity. Accordingly, we tried to define functional couplings in the Poffenberger paradigm; we used a simple choice version of the paradigm, and included a stimulation only (SO) condition for comparison. As an index of functional coupling we employed partial directed coherence, exploiting bilateral grouping of the electrodes to compute intra-and interhemispheric connection weight ratios (CWRs). Our findings indicated modulations in functional weights in relation to the SO condition, rather than the crossed and uncrossed conditions, such that the response executed by the right hemisphere yielded a decrease in intra-, yet an increase in interhemispheric CWRs, whereas the left hemisphere interactions showed connectivity patterns similar to the SO condition irrespective of the side of movement. Overall, our results suggest modulation of connectivity in the same/similar system, which was found to be optimized, in terms of hemispheric asymmetries, to different tasks.
波芬伯格范式是一种著名的半球间传递延迟测量方法，基于交叉与非交叉反应时差异（CUD）进行计算。然而，文献中对CUD的恰当解释存在广泛争议。在本研究中，我们使用连接性测量方法，试图从功能连接的角度解释CUD。因此，我们尝试在波芬伯格范式中定义功能耦合；我们使用了该范式的简单选择版本，并纳入了仅刺激（SO）条件进行比较。作为功能耦合的指标，我们采用了偏定向相干性，利用电极的双边分组来计算半球内和半球间连接权重比（CWR）。我们的研究结果表明，功能权重的调制与SO条件有关，而非交叉和非交叉条件，即右半球执行的反应导致半球内CWR降低，但半球间CWR增加，而左半球的相互作用显示出与SO条件相似的连接模式，与运动侧无关。总体而言，我们的结果表明在同一/相似系统中连接性的调制，发现在半球不对称方面，该系统针对不同任务进行了优化。
