Scientific rational for the collaboration.
There are actually many ambiguities about the methodology used for measuring cortical EP elicited by direct electrical stimulation (in particular the surgical context and the mode of electrical stimulation). The existing literature is quite sparse and scattered considering the pioneer works of the Nobel Price Sir Adrian in 1936 and continuing in the 60’s with the significant work of Goldring et al. (1961, 1994).
More recently, Pr Matsumoto et al. (2004, 2007) was a pioneer to measured CCEP on epileptic patients in order to determine the connectivity in vivo, in the human brain between the stimulation and the recording points.
It is very stimulating from our point of view, in the context of “awake surgery”, to participate with Pr Duffau and Pr Mandonnet to this general understanding (continuing with the surgery of epilepsy) of the “spread of activity in the cerebral cortex” as initially investigated by Sir Adrian in 1936.
However, in studies performed on epileptic patients in our studies performed on patients operated under “awake surgery” for brain tumors, DES parameters employed for electrophysiological brain mapping are significantly different and the measures made by both groups are quite different but very complementary.
Figure 1. Different practices of functional mapping of the brain using electrical stimulation. These practices do not follow precise theoretical rules. Which suggests that they have been determined empirically. The change of stimulation parameters for EMS in monkeys cannot be explained by a simple “scaling”. This variety illustrates our lack of knowledge of the biophysics of electrical stimulation applied to the brain and does not allow us to understand its electrophysiological effects (Vincent et al., 2016).
In consequence, a collaboration between both groups would be fruitful and complementary in order to better understand the electrophysiological effects of DES applied to the human brain for clinical uses and in particular to optimize DES for brain mapping. We probably need now to make a synthesis about the various methodologies to go further and develop new approaches.
