Sleep Problems in Preschoolers With Autism Spectrum Disorder Are Associated With Sensory Sensitivities and Thalamocortical Overconnectivity.

BACKGROUND: Projections between the thalamus and sensory cortices are established early in development and play an important role in regulating sleep as well as in relaying sensory information to the cortex. Atypical thalamocortical functional connectivity frequently observed in children with autism spectrum disorder (ASD) might therefore be linked to sensory and sleep problems common in ASD. METHODS: Here, we investigated the relationship between auditory-thalamic functional connectivity measured during natural sleep functional magnetic resonance imaging, sleep problems, and sound sensitivities in 70 toddlers and preschoolers (1.5-5 years old) with ASD compared with a matched group of 46 typically developing children. RESULTS: In children with ASD, sleep problems and sensory sensitivities were positively correlated, and increased sleep latency was associated with overconnectivity between the thalamus and auditory cortex in a subsample with high-quality magnetic resonance imaging data (n = 29). In addition, auditory cortex blood oxygen level-dependent signal amplitude was elevated in children with ASD, potentially reflecting reduced sensory gating or a lack of auditory habituation during natural sleep. CONCLUSIONS: These findings indicate that atypical thalamocortical functional connectivity can be detected early in development and may play a crucial role in sleep problems and sensory sensitivities in ASD.

Neural correlates of verbal and nonverbal semantic integration in children with autism spectrum disorders.

BACKGROUND: Autism is a pervasive developmental disorder characterized by deficits in social-emotional, social-communicative, and language skills. Behavioral and neuroimaging studies have found that children with autism spectrum disorders (ASD) evidence abnormalities in semantic processing, with particular difficulties in verbal comprehension. However, it is not known whether these semantic deficits are confined to the verbal domain or represent a more general problem with semantic processing. The focus of the current study was to investigate verbal and meaningful nonverbal semantic processing in high-functioning children with autism (mean age = 5.8 years) using event-related potentials (ERPs). METHOD: ERPs were recorded while children attended to semantically matching and mismatching picture-word and picture-environmental sound pairs. RESULTS: ERPs of typically developing children exhibited evidence of semantic incongruency detection in both the word and environmental sound conditions, as indexed by elicitation of an N400 effect. In contrast, children with ASD showed an N400 effect in the environmental sound condition but not in the word condition. CONCLUSIONS: These results provide evidence for a deficiency in the automatic activation of semantic representations in children with ASD, and suggest that this deficit is somewhat more selective to, or more severe in, the verbal than the nonverbal domain.