Laminar and Dorsoventral Molecular Organization of the Medial Entorhinal Cortex Revealed by Large-scale Anatomical Analysis of Gene Expression
(A) Mean expression patterns of layer-specific genes with images in the ABA re-registered data set corresponding to the central reference plane. Scale bar 1mm. (B) Schematic of the central reference image showing the MEC, visual and SS regions overlaid by a color-coded map representing the normalized distance from the inner white matter (0) to the brain surface (1). Pixel intensities were extracted from all locations and binned into 20 groups according to normalized distance. (C) Plots of the distribution of pixel intensities for each MEC layer-specific gene group (see (A)) as a function of distance from the inner white matter border. Error bars represent standard error of the mean. There is a main fixed effect of layer-specific group on neocortical expression (Mixed Model Analysis, F = 22, p < 0.001). Arrows indicate regions of deep and superficial (Sup) neocortex. Laminar boundaries were estimated using individual and mean expression profiles of MEC and SS layer-specific genes (S5 Fig.). (D) Genes with deep layer-specific expression in MEC show significantly more similar expression patterns in their equivalent neocortical layers than in superficial layers (MANOVA, Overall effect of layer-specific group: F(4,174) = 3.3, p = 0.012; Between-subjects effects of layer-specific group: Vis F = 6.7, p = 0.002; SS: F = 6.0, p = 0.004. Tukey’s HSD Vis: Deep < LII: p = 0.002; Deep vs. LIII: p = 0.051; SS Deep < LII: p = 0.04; Deep vs. LIII: p = 0.051). (E) Correlation matrix color represents the Pearson’s correlation coefficient (r) between mean pixel intensity (mINT) in particular layers of MEC, visual and SS cortices for all genes in the re-registered ABA data set.