Overlooked Tertiary Sulci Serve as a Meso-Scale Link between Microstructural and Functional Properties of Human...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Systems Neuroscience

Background:

• The human lateral prefrontal cortex (LPFC) is vital for unique human cognitive functions.
• Neuroanatomical-functional relationships in LPFC are of significant interest.
• Tertiary sulci, shallow cortical indentations, have been largely unexplored in LPFC research.

Purpose of the Study:

• To investigate the role of tertiary sulci in linking microstructural and functional properties of the human LPFC.
• To explore how these overlooked neuroanatomical structures contribute to LPFC organization and function.

Main Methods:

• A multimodal approach was used to manually define 936 neuroanatomical structures in 72 hemispheres.
• Microstructural profiles of myelin content across cortical depths were generated for specific sulci and gyri.
• Resting-state connectivity and meta-analyses of cognitive tasks were employed to assess functional properties.

Main Results:

• A subset of tertiary sulci, including the posterior middle frontal sulcus (pmfs), act as meso-scale links between myelin content and network connectivity in the LPFC.
• The pmfs exhibits distinct myelin content and connectivity profiles across its three components.
• Myelin content varies across cortical depths and between gyral and sulcal components of the middle frontal gyrus (MFG).

Conclusions:

• Tertiary sulci serve as important landmarks for the anatomical and functional organization of the human LPFC.
• These findings support theories of functional hierarchy within the LPFC and the role of sulci as organizational markers.
• The study provides probabilistic sulcal maps of the pmfs, aiding future computational and neuroanatomical research.