Functional Connectivity of the Insula

This chapter is about the use of direct electrical stimulation with short current pulses to estimate from recorded SEEG responses the functional connectivity of the insula. First, we review some studies of the literature which reported both intra-insular and extra-insular connectivity, using the anterior-posterior gyral decomposition of the insula. Second, we present the mapping of the responses to insula stimulation from 301 patients explored in SEEG from the database of the F-TRACT project. We show that the SEEG responses are highly spatially resolved on the whole brain, as demonstrated when comparing the stimulations between the anterior and posterior parts of the insula at different spatial resolution of the Lausanne parcellation scheme. In general, the responses to electrical stimulation of the insula are particularly numerous, in comparison to the stimulation of other areas, which suggests that insula is a structure densely connected to the rest of the cortex.