Figures and data
Cortical input to the parahippocampal region.
(A) We find that the percentage of total cortical area (collapsed across unimodal and transmodal cortices) that projects to the parahippocampal region decreases across species (Spearman’s r=1, p<0.001). (B) Percentage of cortical input to the parahippocampal region calculated separately from the total unimodal and transmodal areas in each species. This analysis demonstrates that even though there is a general decrease in total cortical areas projecting to the parahippocampal region, this decrease disproportionally targets unimodal input.
Cortical input to the entorhinal cortex and to the perirhinal/parahippocampal cortex.
In each species, we calculated the proportion of unimodal and transmodal input separately for the entorhinal cortex and the perirhinal/parahippocampal cortices (postrhinal in the rodent). Our results show that in the primate lineage, cortical input to the entorhinal cortex is consistently more transmodal than to the perirhinal/parahippocampal cortices (z-test for proportion difference, ** p<0.001). In the rat, the proportion of unimodal vs transmodal input is more equally distributed across the entorhinal cortex and perirhinal/postrhinal cortex; ns – not significant.
Unimodal and transmodal cortical areas in the rat.
Unimodal and transmodal cortical areas in the marmoset.
Unimodal and transmodal areas in the macaque.
Unimodal and transmodal areas in the human. Human data were based on the 17-networks parcellation presented in Yeo, Krienen et al.34; note that the human auditory system, including primary and secondary auditory cortex, is included in somatosensory networks; human piriform cortex is believed to occupy the cortical area at the border of the temporal and frontal lobes, around the temporal pole35, and is included in the limbic network. Assignment of the Dorsal Attention Network A and Dorsal Attention Network B to unimodal and transmodal processing was based on connectivity data presented in Reznik et al.13
