A Hong Kong neuroimaging study has found that a brain region involved in language and social processing responds less to emotionally meaningful sentences in autistic children than in their non-autistic peers. The left superior temporal sulcus showed a stronger response to sentences describing people in emotional situations than to sentences about objects in non-autistic children, a social-emotional bias that was reduced among autistic participants. The paper, published in NeuroImage: Clinical, used functional magnetic resonance imaging to monitor brain responses while children listened to Cantonese sentences.
The researchers recruited 78 right-handed Cantonese-speaking children from mainstream schools in Hong Kong. After excluding 20 due to excessive head movement during scanning, the final sample comprised 58 children aged about 8 to 12 (average 10), including 37 autistic and 21 non-autistic participants, with 48 boys in total.
Participants completed assessments of autism symptoms, language comprehension and non-verbal intelligence, while parents provided ratings of their child’s proficiency in Cantonese and English.
During scanning, the children listened to sentences without responding. Social-emotional sentences described people in emotional situations, with half positive and half negative, while object sentences described non-human objects or concepts. By contrast, some sentences were played backward to serve as a non-language sound control. All sentences were eight syllables long and matched for word frequency and grammatical complexity; a single synthetic voice was used for all stimuli so that tone did not differ between sentence types.
Across both groups, the left superior temporal sulcus responded more strongly to social-emotional sentences than to object sentences, indicating that the social-emotional bias observed in adults is already present in children.
When analysed separately, non-autistic children showed a robust social-emotional bias, whereas autistic children showed a weaker bias that did not reach statistical significance.
Within an a priori region of interest, the middle portion of the left superior temporal sulcus, autistic children exhibited a weaker social-emotional bias than non-autistic children, with a moderate-to-large group difference. There were no group differences for backward speech or for object sentences, suggesting similar general hearing and language processing across groups.
The difference appeared to be driven mainly by negative sentences, though the comparison between positive and negative sentences did not reach statistical significance, so the pattern remains tentative.
Language ability did not explain the observed difference. The researchers could not statistically separate the effect from autism symptom level because diagnosis and symptom scores overlapped heavily; within the autistic group, those with more severe symptoms did not show weaker brain responses.
“This reduced activity in the left STS [superior temporal sulcus] in response to social-emotional semantics may contribute to autistic children’s social communication challenges,” the study authors concluded.
The study advances understanding of how autistic children’s brains process the social and emotional meaning in language. However, the authors note several limitations: the sample size is modest by neuroimaging standards, the non-autistic group is comparatively small, and head movement led to the exclusion of a substantial portion of autistic participants. Consequently, the findings may not extend to autistic children who find it difficult to stay still in a scanner. Most participants were boys, and many autistic participants had co-occurring conditions, most commonly ADHD. The study design also cannot fully separate social content from emotional tone.
The paper, titled “Autistic children show reduced activity in left superior temporal cortex in response to social-emotional meaning in language,” was authored by Hanlin Wu, Matthew Ganquan Shi, Phoebe Wai-Yu Chan, Peilun Song, Siu-Fung Lau, Gary Yu-Hin Lam, Xin Kang, Patrick C.M. Wong, and Xiujuan Geng.
