Table II.

The significance from the paired Tukey's test between the four factorial levels of A₁B₁, A₁B₂, A₂B₁, and A₂B₂

Brain regions	A1B2 vs. A1B1	A2B2 vs. A2B1	A2B2 vs. A1B2	A1B1 vs. A2B1	A2B2 vs. A1B1	A1B2 vs. A2B1
Prefrontal system
L orbitofrontal cortex	−	+	+	+	+	ns
R orbitofrontal cortex	−	+	+	+	+	ns
L superior frontal cortex	−	+	+	+	ns	ns
R superior frontal cortex	−	+	+	+	ns	ns
R middle frontal cortex	−	ns	+	+	+	−
Impulsive system
L middle temporal cortex	−	+	+	+	ns	−
R middle temporal cortex	−	+	+	+	ns	−
R precuneus	ns	+	+	ns	+	ns
L fusiform cortex	ns	+	+	ns	+	ns
R fusiform cortex	ns	+	+	ns	+	ns
L amygdala	−	ns	+	ns	+	−
R amygdala	−	+	+	+	ns	ns
VTA	ns	+	+	ns	+	ns

The A₁ and A₂ represent the factor levels of neutral‐cues and heroin‐cues, respectively. The B₁ and B₂ represent the factor levels of nondrug use group and heroin‐dependent group, respectively. In each pair (column) of comparison, the sign (+) indicates that the neural responses are significantly higher in the first factor level than the second; the sign (−) indicates significantly lower. The sign (ns) indicates not significant. The significant level is set at P < 0.01 with multiple comparison correction.