Is the coarse-to-fine processing of fearful face impaired in autism ?: The dissociation between the neural and the behavioral response

International audienceIntroduction:Human visual perception is thought to be coarse-to-fine, with early processing of global information from low spatial frequencies, followed by detailed information processing from high spatial frequencies (Bar et al., 2006; Goffaux et al., 2011). Autistic individuals have a visual perception more oriented toward local information (Mottron et al., 2006), which might partly explain their difficulties in face processing at the behavioral level (Deruelle et al., 2008). However, electrophysiological investigation of spatial frequency processing of faces in autistic children lead to mixed results (Boeschoten et al., 2007; Vlamings et al., 2010) and no study investigated it in autistic adults. We hypothesized that the local bias in the visual perception of autistic adults would disrupt the coarse-to-fine processing of emotional faces, leading to emotion recognition impairment. Method: Autistic adults (N = 44) and typically developed control ( N = 51) matched in sex, education, and IQ (mean IQ = 117) were asked to detect fearful faces among neutral faces, presented during 100 ms. The faces were filtered in two orders, from coarse to fine information (Ctf) of from fine to coarse information (FtC). EEG activity was recorded during the task with 96 active electrodes. P100, N170, and the behavioral response were analyzed.Results:Autistic individuals had longer response time than controls ( p < .001) and this effect did not depend on the order of the sequence. We also showed that P100 latencies of CtF sequences were faster than for FtC sequences ( p = .03) and that N170 of FtC sequences were faster (p < .001) and larger (p < .001) than for CtF sequences, irrespective of the group.Conclusion:Electrophysiological data is consistent with coarse-to-fine processing of fearful faces. Indeed, the earliest component of the visual response (P100) is faster for CtF sequences, in line with the early processing of low spatial frequencies. Additionally, the N170, which is a slightly later component corresponding to more detailed processing of face, is faster and larger for FtC sequences. However, contrary to our hypothesis, this coarse-to-fine processing seems intact in autistic adults, despite a longer response time for fearful detection. Findings suggest that the difficulties for autistic adults to process emotional faces are related to a higher order of processing than primary visual processing