Spatial distribution and specific geometric and topological patterning of early sulcal folds have been hypothesized to be under stronger genetic control and are more associated with optimal organization of cortical functional areas and their white matter connections, compared to later developing sulci. Several previous studies of sulcal pit (putative first sulcal fold) distribution and sulcal pattern analyses using graph structures have provided evidence of the importance of sulcal pits and patterns as remarkable anatomical features closely related to human brain function, suggesting additional insights concerning the anatomical and functional development of the human brain (Im and Grant, Sulcal pits and patterns in developing human brains. Neuroimage 2019).

The spatial pattern of the sulcal pits was relatively invariant between individuals, compared to the more superficial cortical regions and later developing sulci (Im et al., Cereb Cortex 2010). We recently investigated temporal patterns of emergence and spatial distribution of sulcal pits in the second half of gestation. The position and spatial variance of sulcal pits in the fetal brain are similar to those in the adult brain, and they are also temporally uniform against dynamic brain growth during fetal life (Yun et al., Cereb Cortex 2020). The sulcal pit has proven effective for characterizing genetically influenced early cortical folding development

We have demonstrated the functional implication of the sulcal pit distribution (Im et al., Cereb Cortex 2010; Im et al., Neuroimage 2011; Im et al., Plos One 2013).

We first developed a quantitative sulcal pattern analysis technique using a sulcal pit-based graph structure that completely characterizes the geometric and topological pattern of primary cortical folds (Im et al., Neuroimage 2011). This method was applied to a twin MRI study and the similarity of the sulcal graphs in twin pairs was significantly higher than in unrelated pairs. We recently examined intergenerational transmission of cortical sulcal patterns from mothers to their children and detected stronger sulcal pattern similarity for child-mother pairs (Ahtam et al., Cereb Cortex 2020). These studies support a genetic influence on sulcal patterning.

Abnormal sulcal patterns have been found in several developmental disorders (Im et al., Cereb Cortex 2013; Bae et al., Science 2014; Im et al., Cereb Cortex 2016; Smith et al., Neuron 2018; Morton et al., Cereb Cortex 2020; Vasung et al., Cereb Cortex 2020).