Table 1.

Summary of the anatomical labels used in the manual segmentation protocol

Abbr.	Name	Comments
Primary labels
CA1 CA2 CA3	Cornu ammonis Fields CA1‐3	CA labels include stratum pyramidale and stratum oriens. The hypointense layer of voxels (understood to combine the CA strata radiatum, lacunosum and moleculare [SRLM]; the vestigial hippocampal sulcus [HS]; and stratum moleculare of the DG) is split evenly between the CA and DG labels. The CA2 and CA3 subfields are labeled in the posterior portion of the hippocampal head and in the body; elsewhere they are merged into the CA1 label.
DG	Dentate gyrus	Includes the inner half of the hypointense band; the polymorphic and granular cell layers; and the hilus, which some authors consider to be CA4. [Duvernoy, 2005; Lorente de Nó, 1934]
SUB	Subiculum	Includes subiculum proper, presubiculum and parasubiculum. SUB is labeled in the head and body, but not in the tail of the hippocampus.
MISC	Miscellaneous	Used to label cysts and cerebrospinal fluid in the hippocampus.
ERC	Entorhinal cortex	The ehMTL structures are labeled beginning at the most anterior slice of the hippocampal body and ending one slice past the most anterior slice of the hippocampal head.
BA35	Brodmann area 35
BA36	Brodmann area 36
CS	Collateral Sulcus
Compound labels (only used for analysis)
CA	Cornu ammonis	Combines labels CA1, CA2, and CA3
HIPP	Hippocampus	Combines labels CA, DG, and SUB
PRC	Perirhinal cortex	Combines labels BA35 and BA36

Details of the segmentation protocol are provided in the Supporting Information Material. The top portion of the table lists the “primary” labels, that is, those assigned to voxels by manual segmentation. The bottom portion lists derived “compound” labels, which are only used in the analysis. Compound labels are derived by merging groups of primary labels (e.g., CA merges labels CA1, CA2, and CA3).