We asked him about the importance of their results:
"The significance of this study is twofold:
Our causality analysis as a "reverse engineering" determined the form of dependency between intrinsic optical signals and electrical measurements in the neural tissue. This raises the possibility of unifying the high spatial but low temporal resolution of optical measurements with the high temporal but low spatial resolution of electrical signals, for which the transparent electrode array is an optimal instrument.
On the other hand, causality analysis is worth attention in is own right: our study highlighted the difference between correlation and causality and demonstrated that it is possible to determine the directed causal connection in the neural system (and distinguish it from circular causal connection) just observing the data, even if the time scale of the two data series is 500 times different. Such an analysis can help to disentangling interactions in the brain, during information processing and cognitive activity as well."