Proteomic insights into the macaque insular parcellation based on structural connectivity gradients

Area of Science:

• Neuroscience
• Brain Imaging
• Genomics

Background:

• Primate brains exhibit gradients across microstructure, macro-connectivity, and gene expression.
• The macaque insula's microstructural transitions are known, but its macro-connectivity and gene expression gradients are unclear.

Purpose of the Study:

• To investigate structural connectivity (SC) gradients in the macaque insula.
• To determine the relationship between SC gradients and gene expression.
• To test if SC gradients drive insular parcellation.

Main Methods:

• Analysis of high-resolution diffusion-weighted MR imaging data.
• Integration with spatially aligned proteomic data.
• Gradient analysis to identify patterns and correlations.

Main Results:

• A rostrocaudal organization of the dominant SC gradient was identified in the macaque insula.
• The first two SC gradients revealed a distinct four-subregion parcellation pattern.
• Proteomic profiles strongly correlated with the dominant SC gradient and aligned with the four-subregion pattern.
• SC gradients better explained protein expression variations than cortical thickness or T1w/T2w maps.

Conclusions:

• SC gradient analysis successfully identified a four-subregion parcellation of the macaque insula.
• This parcellation is strongly supported by spatial gene expression patterns.
• SC gradients are a key factor in understanding insular organization and heterogeneity.