Abnormal brain synchrony in Down Syndrome.

Area of Science:

• Neuroscience
• Genetics
• Cognitive Science

Background:

• Down syndrome is the leading genetic cause of intellectual disability.
• The underlying pathophysiology of cognitive impairment in Down syndrome remains largely unknown.

Purpose of the Study:

• To investigate brain connectivity patterns in individuals with Down syndrome using functional magnetic resonance imaging (fMRI).
• To compare brain synchrony in Down syndrome with typically developing individuals and individuals with autism.

Main Methods:

• fMRI scans were acquired from 15 individuals with Down syndrome and 14 controls viewing cartoon videos.
• Brain connectivity and network structure were analyzed.
• Data were compared with resting-state fMRI data from the Autism Brain Imaging Exchange (ABIDE) dataset.

Main Results:

• Widespread increased synchrony between brain regions was observed in Down syndrome, with some distant connections showing underconnectivity.
• Brain regions with negative correlations were less anticorrelated, indicating altered functional relationships.
• Increased internetwork correlation was linked to lower performance IQ in Down syndrome subjects.
• Functional brain organization in Down syndrome appeared simplified and locally driven.
• Despite increased synchrony, Down syndrome subjects showed lower correlation to external stimuli, suggesting idiosyncratic patterns.

Conclusions:

• Findings suggest immature brain development in Down syndrome, characterized by altered connectivity and impaired integration of information across distant brain regions.
• The observed connectivity patterns in Down syndrome are distinct from those seen in autism.
• These results provide insights into the neural basis of cognitive impairment in Down syndrome.