Abstract
Prior research has shown that magnocellular (M) pathways are less mature than parvocellular (P) pathways during adolescence, which might explain why adolescents have difficulties recognizing facial expressions. M pathways (associated with holistic face processing) should drive the face inversion effect more than the P pathways (which play an important role in analyzing finer facial features). Therefore, adolescents should show greater immaturities in the face inversion effect for faces filtered with low pass (LP) than with high pass (HP) spatial frequency filters. In this study, adults and adolescents viewed upright and inverted faces and objects (chairs) that were either unfiltered, LP or HP filtered. Consistent with prior research, we found that P1 and N170 were sensitive to inversion for face stimuli, but not for other stimuli. For adults, the face inversion effect on N170 amplitude was larger for fearful faces than for happy faces, but the opposite was true for adolescents. This finding is consistent with other reports that show face processing develops more quickly for happy than for fearful faces. We also found that the P1 and N170 face inversion effect was differentially modulated by LP and HP spatial frequency filtration. The face inversion effect for N170 amplitude was attenuated in the HP condition compared to the LP and unfiltered conditions. Notably, adults and adolescents showed topographical differences in their P1 inversion effect for LP faces. For adults, we found the P1 amplitude inversion effect to be larger over the right hemisphere (as is commonly reported), whereas for adolescents, it was larger over the left hemisphere. Our data suggest that the neural correlates of face processing are still maturing during adolescence. Furthermore, these immaturities were more apparent for stimuli that accentuated the contributions of the M pathways.
Meeting abstract presented at VSS 2015