Figure 10. The grand average waveform of N170 elicited in the left and right hemisphere. The two face stimulus (Complete/ Incomplete ) and four electrode sites (PO7/PO8/P7/P8) were averaged.
With regard to the amplitude of the N170 component, the main effect of time was significant [F (3,51) = 5.09, p = 0.004, ηp2 = 0.23], and the amplitude of N170 in Test 2 was larger than that in Test 1 (-5.48 ± 0.59 μVvs. -4.17 ± 0.45 μV) (Figure 7). The main effect of hemisphere was significant [F (1,17) = 10.92, p = 0.004, ηp2 = 0.39], and the amplitude of N170 in the right hemisphere was larger than that in the left hemisphere (-5.48 ± 0.54 μV vs. -4.17 ± 0.55 μV) (Figure 10). The main effect of the face stimulus was significant [F (1,17) = 14.27, p = 0.002, ηp2 = 0.46], and the amplitude of N170 in the complete condition was larger than that in the incomplete condition (-5.50 ± 0.50 μV vs. -4.15 ± 0.57 μV) (Figure 8).
The interaction between time and face stimulus was significant [F (3,51) = 7.71, p < 0.001, ηp2 = 0. 31]. In the complete condition, the N170 amplitude was larger in Test 2 than in Test 1 (-6.39 ± 0.60 μV vs. -4.55 ± 0.47 μV, p = 0.001) (Figure 9 and Table 3). The interaction between hemisphere and time was significant [F (3,51) = 3.40, p = 0.024, ηp2 = 0.17]; in the right hemisphere, the N170 amplitude was larger in Test 2 (-5.92 ± 0.60 μV,p = 0.023) and Test 3 (-6.05 ± 0.74 μV, p = 0.014) than in Test 1 (-4.40 ± 0.45 μV) (Fig 11 and Table 3). No other significant main effects or interactions were found.
Table 3. The peak amplitude and peak latency of N170 (M ±SD )