Neural differences in social and figurative language processing on the autism spectrum

Area of Science:

• Neuroscience
• Psycholinguistics
• Cognitive Science

Background:

• Individuals on the autism spectrum often experience challenges with social and figurative language comprehension.
• Neural regions supporting social cognition and language semantics, including the anterior temporal lobe (ATL), ventro-medial prefrontal cortex (vmPFC), posterior cingulate cortex (PCC), and posterior middle temporal gyrus (pMTG), show overlap.
• Disentangling the neural underpinnings of social and figurative language difficulties in autism spectrum disorder is complex due to overlapping cognitive and neural systems.

Purpose of the Study:

• To investigate the neural differences between individuals with autism spectrum disorder (AUT) and a non-autistic comparison (NAC) group in processing social and figurative language.
• To examine how manipulating social/nonsocial and figurative/literal dimensions of adjective-noun phrases affects brain activation.
• To test the hypothesis that individuals with autism spectrum disorder exhibit greater activation differences for more social and figurative stimuli.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan participants.
• Nineteen individuals in the AUT group and 22 in the NAC group performed familiarity judgments on 192 adjective-noun phrases.
• A 2x2 factorial design manipulated social/nonsocial and figurative/literal properties of the phrases.

Main Results:

• Social phrases activated the PCC in both groups; vmPFC activation was observed only in the NAC group.
• The AUT group rated figurative phrases as more literal and showed no significant activation for the figurative-literal contrast.
• The key group-level neural difference was greater activation in the right ATL for the AUT group in the social-figurative condition.

Conclusions:

• Differences in the right ATL and pMTG in the AUT group suggest altered recruitment of right-hemisphere semantic network homologues.
• These findings indicate distinct neural processing for combined social and figurative language in individuals with autism spectrum disorder.
• The study highlights potential neural mechanisms underlying social and figurative language comprehension difficulties in autism spectrum disorder.