In this study, we applied a surface-based laminar analysis pipeline available in FreeSurfer (https://surfer.nmr.mgh.harvard.edu/) to process high-resolution anatomical data with a 0.6 mm isotropic resolution and to delineate the six layers of the cortex [56, 57]. To investigate whether FC is sensitive to layer-specific connectional architecture, we examined this aspect with high-resolution resting state fMRI data (voxels with 0.85 mm in-plane resolution) obtained at 7 T. A simple blind deconvolution technique [58] was used to obtain the latent neural signals for each layer. Specifically, we tested the following hypotheses regarding thalamo-cortical and cortico-cortical layer-specific microcircuits derived from previous invasive anatomical studies (Fig. 1): (1) FC between the entire thalamus and cortical layers I and VI must be significantly greater than between the whole thalamus and other layers. This follows from evidence in rat brain tracing studies which show that regions across the cortex receive inputs to layer I from M-type thalamic neurons distributed in most thalamic nuclei [59–64]. In addition, pyramidal neurons in layer-VI are known to target all thalamic nuclei. Furthermore, FC between somatosensory thalamus (ventral posterolateral nucleus, VPL)
