Computing geometric layers and columns on continuously improving human (f)MRI data

This article provides a bird's-eye view of the technology developments that allow researchers to study mesoscale functional details of the human cortex. These technologies include fMRI data acquisition and sampling methods to investigate the cortical landscape (e.g. layers, and columns). We aim to give an overview on methods for computing the geometric layer and columns of the human cortex in the context of continuously improving fMRI data. Specifically, we discuss layerification (computation of geometric layers), and columnification (computation of geometric columns) types of the cortical gray matter. We discuss their geometric and algorithmic motivations based on cortical cytoarchitecture, myeloarchitecture, and angioarchitecture and we give an overview of current implementations and their underlying data structures. The developments discussed here are giving researchers a non-invasive “mesoscope” to observe the living human brain. As the layer fMRI tools become more streamlined, they become more accessible to a wider group of researchers. Therefore, the brief history together with the current trajectory of high resolution fMRI data acquisition and analysis methods show that layer fMRI tools are well positioned to become a part of the standard toolkit of neuroscientists in near future.