Relative gene expression in hippocampus at the time of euthanasia. Gene expression of seven target genes was measured by qPCR. For each gene, the expression levels are normalized relative to the PRNP+/+ group (= 1). Bars display mean expression (± SEM) with asterisks representing significant differences (p < 0.001) assessed by one-way ANOVA with Tukey post hoc test. n = 12 (4 PRNP+/+, 4 PRNP+/Ter, and 4 PRNPTer/Ter).