Figure 2. Segmentation scheme of entorhinal and hippocampal subregions and layer-specific sample activation.

(a) Single-subject high resolution T2* image (resolution: 0.33 mm² in-plane, 1.5 mm slice thickness) with overlaid entorhinal (EC; left panel) and hippocampal (HC; right panel) ROIs on two coronal slices. ROIs were manually segmented on the individual T2* images and coregistered to the mean EPIs. The EC was equally divided into three regions: superficial, middle and deep. The CA1 region in the hippocampal body was subdivided into apical (Nr. 3) and pyramidal regions (Nr. 2). Note that the apical dendritic layer of CA1 (‘SRLM’) is well visible as a dark band on T2-weighted images. (b) Individual mean functional MR image (EPI, resolution: 0.8 mm³) showing anterior MTL regions (EC, PRC and hippocampal head; left panel) and more posterior MTL regions (PHC and hippocampal body; right panel). (c) Single-subject (peak) activation due to memory (DM, or successful encoding) overlaid on the individual mean EPI and the coregistered T2* and MPRAGE image (smoothing: 1.5 mm, P_{voxel level} <0.01, k≥10 voxels). This demonstrates that activation can be confined to deep (vs superficial subregions) of the EC. For single-subject peak activation see also Supplementary Fig. 2.