19992
Conscious and Nonconscious Emotional Processing and Level of Autistic Traits
Difficulty with emotion perception is a core feature of autism spectrum disorder (ASD) that is associated with the broader phenotype. Emotion processing is subserved by complex, densely connected yet separable cortical and subcortical brain systems. Conscious processing is a complex process involving multiple systems, whereas the subcortical visual processing pathway is hypothesized to be a simpler, rapid system. Most investigations of face processing deficits in ASD have focused on cortical pathways, such as the fusiform gyrus and superior temporal sulcus. More recently, evidence from neuroimaging studies implicates subcortical circuitry in the neuropathology of ASD. However, few studies have been replicated, and temporal characteristics of this subcortical route remain unexplored.
Objectives:
The current study explored the neural underpinnings of conscious and nonconscious perceptions of affect in typically developing individuals with varying levels of autistic-like traits (measured with the Autism Quotient (AQ)). We investigated the relationship between autistic-like traits and face processing efficiency as measured with event-related potentials (ERPs). The temporal sensitivity of this neuroimaging technique enabled relative reliance upon cortical versus subcortical routes of perception.
Methods:
We utilized ERPs (the P100, N170, and P300) to measure differences in face processing for emotional faces that were presented (a) either too quickly to reach conscious awareness (16 ms) or (b) slowly enough to be consciously observed (200 ms). Data were collected from 36 typically developing adults (M = 22.51 years, SD = 1.72, 13 females).
Results:
All individuals (regardless of AQ score) evidenced increased P100 (p <.01) and P300 (p = .01) for non-conscious versus consciously presented faces. Individuals with high AQ scores evidenced delayed early ERP components related to faces (P100, N170). Specifically, individuals with high AQ scores had delayed P100 component to subliminally presented faces (p = .006), as well as to neutral faces, particularly in the right hemisphere (p = .019), and delayed N170 to neutral faces (p = .002).
Conclusions:
Non-consciously perceived emotional faces elicited enhanced neural responses regardless of AQ score. Furthermore, higher levels of autistic traits were associated with inefficient face perception (i.e., longer latency to face-sensitive ERP components). This delay parallels processing delays observed in ASD. These data suggest that inefficient social perception is present in individuals with sub-clinical levels of social impairment and is observed in both cortical and subcortical pathways.