Overwhelmed by the man in the moon? Pareidolic objects provoke increased amygdala activation in autism.

An interesting feature of the primate face detection system results in the perception of illusory faces in objects, or pareidolia. These illusory faces do not per se contain social information, such as eye-gaze or specific identities, yet they activate the cortical brain face-processing network, possibly via the subcortical route, including the amygdala. In autism spectrum disorder (ASD), aversion to eye-contact is commonly reported, and so are alterations in face processing more generally, yet the underlying reasons are not clear. Here we show that in autistic participants (N=37), but not in non-autistic controls (N=34), pareidolic objects increase amygdala activation bilaterally (right amygdala peak: X = 26, Y = -6, Z = -16; left amygdala peak X = -24, Y = -6, Z = -20). In addition, illusory faces engage the face-processing cortical network significantly more in ASD than in controls. An early imbalance in the excitatory and inhibitory systems in autism, affecting typical brain maturation, may be at the basis of an overresponsive reaction to face configuration and to eye contact. Our data add to the evidence of an oversensitive subcortical face processing system in ASD.