Uncovering a tripartite landmark in posterior cingulate cortex

Abstract

Understanding brain structure-function relationships, and their development and evolution, is central to neuroscience research. Here, we show that morphological differences in posterior cingulate cortex (PCC), a hub of functional brain networks, predict individual differences in macroanatomical, microstructural, and functional features of PCC. Manually labeling 4511 sulci in 572 hemispheres, we found a shallow cortical indentation (termed the inframarginal sulcus; ifrms ) within PCC that is absent from neuroanatomical atlases yet colocalized with a focal, functional region of the lateral frontoparietal network implicated in cognitive control. This structural-functional coupling generalized to meta-analyses consisting of hundreds of studies and thousands of participants. Additional morphological analyses showed that unique properties of the ifrms differ across the life span and between hominoid species. These findings support a classic theory that shallow, tertiary sulci serve as landmarks in association cortices. They also beg the question: How many other cortical indentations have we missed?

Distinct population and single-neuron selectivity for executive and episodic processing in human dorsal posterior cingulate

“…As precision functional data might not always be available for individuals, how might functional organization within PCC be inferred? Our electrophysiological observations are broadly consistent with recent large-scale examination of PCC sulcal anatomy which identified a new tertiary sulcus (inframarginal sulcus) as a useful landmark for the transition from DMN to CCN within dPCC ( Willbrand et al, 2022 ). Further integration of invasive electrophysiology and precision neuroimaging within subjects will be critical for elucidating key features of PCC functional neuroanatomy and its variability across individuals ( Gordon et al, 2017b ).…”

“… ( A ) Anatomical locations, normalized to MNI space, of intracranial sEEG depth electrodes targeting the posterior aspect of the cingulate cortex, with the distal contact of probes containing microwires indicated in green. ( B ) Anatomy of human PCC, differentiating dorsal (dPCC) and ventral (vPCC) subregions and demarcating regional sulci following the most recent definitions in PCC ( Petrides, 2018 ; Willbrand et al, 2022 ). ( C ) Attention/Memory Switch task procedure and example stimuli.…”

Development of human lateral prefrontal sulcal morphology and its relation to reasoning performance

“…After defining LPFC sulci in FreeSurfer, we extracted the following morphological metrics from each sulcal label file: sulcal depth (mm), surface area (mm 2 ), cortical thickness (mm), and local gyrification index (lGI). We selected sulcal depth and surface area as these metrics are prominent features of sulci (Sanides, 1964;Chi et al, 1977;Welker, 1990;Armstrong et al, 1995;Weiner et al, 2014Weiner et al, , 2018Lopez-Persem et al, 2019;Madan, 2019;Petrides, 2019;Weiner, 2019;Miller et al, 2020Miller et al, , 2021aMiller et al, , 2021bNatu et al, 2021;Voorhies et al, 2021;Li et al, 2022;Willbrand et al, 2022aWillbrand et al, , 2022bYao et al, 2022). We further selected cortical thickness and lGI since the longitudinal development of these features was previously analyzed at the lobular level (Alemán-Gómez et al, 2013).…”

“…Mean lGI values (a value comparing the amount of cortex buried within sulci to the amount of cortex on the outer visible cortex, or hull) were extracted with the mris_anatomical_stats function with the pial_lgi flag in FreeSurfer (Fischl and Dale, 2000). As in prior work (Miller et al, 2020;Voorhies et al, 2021;Willbrand et al, 2022aWillbrand et al, , 2022b Although prior work examining sulcal morphology studied sulcal width (for example see Alemán-Gómez et al, 2013;Jin et al, 2018;Carmona et al, 2019), we found that the current toolbox that can extract this information from individual sulcal labels in FreeSurfer (Madan, 2019) failed to obtain the width of many of the smaller sulci in LPFC. Thus, we were not able to examine this feature in the present study.…”

“…Conversely, our results did present a difference in most features between children/adolescents and young adults. It is also plausible then that the most pronounced changes in LPFC sulcal morphology occur during the prenatal period and early childhood (Dubois et al, 2008;Meng et al, 2014;Le Guen et al, 2018;Im and Grant, 2019;Aslan Çetin and Madazlı, 2021), and again in older adulthood (Liu et al, 2013;Madan, 2021;Tang et al, 2021;Willbrand et al, 2022a).…”