Correlation of cellular and clinical parameters. (a) Correlation between age at surgery and the density of calbindin-positive cells in isolated frontal and temporal FCD and FCD IIIa. We found a significant correlation (r2 = 0.13) of lower density of calbindin-positive cells with lower age at surgery. (b) Ratio of TLE4/NeuN positive cells for patients with daily or monthly seizures. Patients with monthly seizures had a significantly lower ratio of TLE4-positive cells (Student’s t-test, p = 0.004). Please note that most FCD IIIa cases are in the group with monthly seizures whereas isolated FCD cases have daily seizures. (c) Density of calbindin-positive cells in patients with daily or monthly seizures. Patients with daily seizures have significantly less calbindin-positive cells (Student’s t-test, p = 0.029). Again, note the distribution of the different FCD cases within the two seizure groups.