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Functional conenctivity; In vivo parcellations; Prefrontal cortex; Neuroanatomy
Abstract:
Human and nonhuman primates exhibit flexible behavior. Functional, anatomical, and lesion studies indicate that the lateral frontal
cortex (LFC) plays a pivotal role in such behavior. LFC consists of distinct subregions exhibiting distinct connectivity patterns that
possibly relate to functional specializations. Inference about the border of each subregion in the human brain is performed with the aid
of macroscopic landmarks and/or cytoarchitectonic parcellations extrapolated in a stereotaxic system. However, the high interindividual
variability, the limited availability of cytoarchitectonic probabilistic maps, and the absence of robust functional localizers render the in
vivo delineation and examination of the LFC subregions challenging. In this study, we use resting state fMRI for the in vivo parcellation
of the human LFC on a subjectwise and data-driven manner. This approach succeeds in uncovering neuroanatomically realistic subregions,
with potential anatomical substrates includingBA46, 44, 45, 9 and related (sub)divisions. Ventral LFC subregions exhibit different
functional connectivity (FC), which can account for different contributions in the language domain, while more dorsal adjacent subregions
mark a transition to visuospatial/sensorimotor networks. Dorsal LFC subregions participate in known large-scale networks obeying
an external/internal information processing dichotomy. Furthermore, we traced “families” of LFC subregions organized along the
dorsal–ventral and anterior–posterior axis with distinct functional networks also encompassing specialized cingulate divisions. Similarities
with the connectivity of macaque candidate homologs were observed, such as the premotor affiliation of presumed BA 46. The
current findings partially support dominant LFC models.
