Language networks in Autism Spectrum Disorder: A systematic review of connectivity-based fMRI studies

Area of Science:

• Neuroscience
• Developmental Psychology
• Psychiatry

Background:

• Autism Spectrum Disorder (ASD) is characterized by neural connectivity differences.
• Language networks are well-defined in neurotypical (NT) individuals and linked to core ASD features.
• Language-based functional connectivity offers a unique lens to study ASD.

Purpose of the Study:

• To systematically review language-related functional connectivity in individuals with ASD.
• To characterize connectivity patterns during language tasks and at rest.
• To explore associations between connectivity and ASD symptomology/language skills.

Main Methods:

• Systematic literature review of 96 studies.
• Databases searched: PubMed, PsychInfo, Scopus, ProQuest, Google Scholar.
• Analysis of language-task and resting-state functional connectivity studies.

Main Results:

• Language-task studies revealed local over-connectivity and global under-connectivity within and outside the language network in ASD.
• Resting-state studies showed mixed connectivity patterns.
• Connectivity patterns were associated with ASD symptom severity and language abilities.

Conclusions:

• Language-task functional connectivity in ASD is characterized by local over-connectivity and global under-connectivity.
• This pattern, rather than a simple local-global distinction in resting-state, may define ASD.
• Heightened language-related connectivity might support social functioning in ASD.