NEURAL BASIS OF ATTENTION ORIENTING ABNORMALITIES IN CHILDREN WITH AUTISM

Detection of new events occurring outside the focus of attention is fundamental to adaptive functioning and is most critical when attention is focused elsewhere. The unattended novel sensory events may demand further analysis according to their task relevance and may appear important for survival. Behavioral and physiological findings reviewed in this article imply that brains of many people with autism spectrum disorders (ASD) are, to a certain extent, impenetrable to such unattended but potentially salient changes in the immediate sensory environment. Here we reviewed neurophysiological studies investigating neural processing of salient (rare, novel or deviant) auditory stimuli in ASD. We put forward a hypothesis that atypical processing of deviance and novelty in a proportion of individuals with ASD may be grounded in the failure of nicotinic cholinergic arousal pathways to engage cortical mechanisms involved in detection of changes in the environment and appraisal of their novelty, if these changes occur beyond the currently attended sensory stream. Further studies linking neurophysiological findings with attention behavior and those searching for their neurochemical and genetic bases will help to understand causes of attention problems and sensory modulation difficulties in children with ASD and may prove helpful to direct early intervention.