Table 4. Candidate HKGs in BestKeeper evaluation.

Rank	Temporal Cortex		Frontal Cortex		Hippocampus		Hypothalamus		Total
	Gene	R	Gene	R	Gene	R	Gene	R	Gene	R
1	HPRT	0.94	ACTB	0.889	ACTB	0.926	ACTB	0.954	GAPDH	0.853
2	β2M	0.912	GAPDH	0.859	HPRT	0.923	GAPDH	0.943	β2M	0.677
3	ACTB	0.905	β2M	0.754	GAPDH	0.831	β2M	0.901	HPRT	0.676
4	GAPDH	0.882	HPRT	0.623	β2M	0.81	HPRT	0.896	18S	0.585
5	18S*	0.199	18S	0.544	18S	0.615	18S	0.67	ACTB	0.558

Ranking of candidate HKGs by BestKeeper for each brain structure and all structures together, as described by total. Higher correlation coefficients (R) indicate more stable genes. All values achieved a significance of P<0.05, according to Pearson correlation analysis, with the exception of 18S in the temporal cortex. A cut-off value of P>0.05 was used for Pearson correlation analysis was set. *:P>0.05.