Table 1.

Summary of microarray results in three regions of rat brain after chronic treatment with levetiracetam (Levet) or phenytoin (Phen)

Drug	Region	No. expressed transcripts	No. transcripts with mean >150% or <67% of control	No. transcripts >150%or <67% of control and FDR < 0.01
Levet	Pons/medulla	9,765	114	65
Phen	Pons/medulla	9,861	45	3
Levet	Hippocampus	9,507	48	2
Phen	Hippocampus	9,938	223	64
Levet	Frontal cortex	9,771	75	1
Phen	Frontal cortex	9,898	496	327

The rat 230.2 GeneChip was used, which contained probe sets representing 16,165 unique transcripts (Dai et al., 2005). Each row represents data from 6 to 7 control or drug-treated animals. The third column shows the number of expressed transcripts with above-background signals in all or all but one control or drug-treated animals. The fourth column shows the number of transcripts with expression >150% or <67% of control as calculated from mean values, whereas the fifth column shows the number of differentially expressed transcripts after controlling for a false discovery rate (FDR) of <0.01 [one-way analysis of variance (ANOVA) with Benjamini and Hochberg (1995) correction for multiple comparisons].