Sigmaplot version 10

Data were divided into four groups for the comparison. These four groups are nontumor control brain tissues, low-grade (both Grade I and Grade II) astrocytomas, Grade III astrocytomas, and Grade IV astrocytomas. For various parameters, the data are presented as box plots created using SigmaPlot version 10.0.1 (Systat Software Inc., San Jose, CA, USA) [34 ]. Statistical analysis was performed using IBM SPSS Statistics version 22.0 software (IBM, Armonk, NY, USA) [35 ]. The nonparametric Mann–Whiney U test was used to determine the statistical significance for the differences between any two groups for all the measured parameters. The nonparametric Spearman’s correlation analysis was conducted to examine the significance of the correlations between the malignancy degree (1 to 4 for the groups of nontumor controls, low grades, Grade III, and Grade IV, respectively) or GOS grade (“G” = 1, “M” = 2, “S” = 3, “V” = 4, and “D” = 5) and various parameters. Differences were considered statistically significant when p values were less than 0.05.

Patch-clamp data were analyzed using Clampfit 9.2 (Axon Instrument, Sunnyvale, CA, USA). The Vh and k of the steady-state activation curves were determined using Boltzmann functions and choosing the best fit one for the curve. To determine the recovery time constants of the resurgent current, responses of each cell were fitted to a first-order exponential function, and the time constants derived were averaged from cells as indicated. Statistical analysis was done using the statistical software Sigmaplot version 10.0 (Systat Software Inc.,wpcubed GmbH, Erkrath, Germany). Student’s independent t-test and ANOVA followed by two-tailed Bonferroni’s correction were used to test the differences between groups. Statistical significance was defined as p < 0.05.