SEEG functional connectivity in TLS. a. A study of functional coupling between entorhinal cortex and amygdala in a patient with mesial temporal lobe seizures. An increase of synchrony (1) during the phase of preictal spiking is observed as measured by the coefficient h2 between the two structures. The direction index D indicates that the activity in the entorhinal cortex is leading (negative values) that recorded in the amygdala. Note that the rapid discharge is associated with a decrease of correlation (reproduced from ). b. Boxplot performed on normalized values of correlations (h2) between signals recorded from amygdala, entorhinal cortex and hippocampus during SEEG recorded mesial temporal lobe seizures. The lower and upper lines of each “box” (25th and 75th percentiles of each sample) and the line in the middle of the box (sample median) respectively indicate that the distributions of h2 values over the BKG, BRD and DRD periods are narrower than that computed over the ARD period. h2 values measured before the rapid discharge (BRD) are significantly higher than those measured during background activity (BKG) and during the rapid discharge itself (DRD). For the period that follows the rapid discharge (ARD) strong re-coupling is indicated by significantly high h2 values (adapted from ).