A team of researchers from the University of Geneva (UNIGE), Switzerland, introduces direct evidence of hindered development during the toddler to pre-school years in autism.
As infants develop, they preferentially move towards and respond to social cues such as voices, faces, and human gestures. At the same time, their brain develops a network of regions that specialize in translating these cues, known as the ‘social brain’.
However, a usual observation in infants later diagnosed with Autism Spectrum Disorders (ASD) is lessened sensitivity and attention towards these social cues during the first year of life. This discernible apathy to social cues is thought to eventually hinder the normal development of the social brain at early developmental stages.
Their findings are published in the journal eLife.
Dr Holger Sperdin, Postdoctoral Research Associate at the UNIGE’s Faculty of Medicine and lead author of the study, explains what he and his team set out to discover, “As toddlers with ASD have less preferential attention for social cues, we hypothesised that when we showed them moving social images, they would demonstrate differences in both the way they visually explore these images and in the way their brain networks process social information, compared with typically developing toddlers.”
The team used an electrophysiological monitoring method called electroencephalography (EEG) to study the children’s brain activity, and powerful eye-tracking technology to examine their gaze while they watched movies featuring human social interactions.
During this, they discovered that the children with ASD had dissimilar gaze patterns while watching the movies to the typically developing infants and that this was accompanied by alterations in nerve cell connectivity and data flow in the brain.
In those with ASD, the team likewise examined what is known as ‘increased driving’ in two specific frequencies of brain waves, alpha, and theta as well as high levels of connectivity between nerve cells in certain regions in the brain. The theta brainwaves frequency and the regions of the brain affected are both known to be prominent components of the ‘social brain’, and the alpha frequency is important for visual attention.
These results show the first evidence that differences in the visual exploration of images coincide with alterations in connectivity between key regions of the social brain in very young children with ASD. Brain regions generating these brainwaves frequencies may, therefore, develop differently in children with ASD compared with their typically developing peers.
Senior author Professor Marie Schaer, Assistant Professor at the University of Geneva, Switzerland stated, “Our results show for the first time the presence of alterations in information flow from brain areas involved in social cue processing in toddlers and pre-schoolers with Autism Spectrum Disorders (ASD).”
“These alterations within regions of the social brain are present at early stages of ASD and justify further investigation into whether therapeutic interventions targeting social orienting skills may help to remediate social brain development during this critical stage when neural plasticity is still possible.”
The results of their study suggest that interventions targeting children’s ability to respond to social cues at this critical early age could rewire the brain while it is still possible to do so, potentially restoring social brain development.
This research may open the way to new therapeutic interventions at early stages when neural plasticity is still possible.