Detailed segmentation of human hippocampal and subicular subfields using a combined approach

Hippocampal and subicular subfields (dentate gyrus, CA4, CA3, CA2, CA1, prosubiculum, subiculum, presubiculum and parasubiculum) of human brains have become the major targets of extensive ex vivo and in vivo neuroimaging studies. The subfield segmentation in previous studies relied heavily on parcellation based on conventional Nissl stains. Our recent study (Ding and Van Hoesen, J Comp Neurol, 523:2233-2253, 2015), however, has revealed significantly more reliable and accurate parcellation of all the subfields in both hippocampal head and body regions using a combined approach. This approach combines traditional Nissl staining and modern neurochemical labeling on closely adjacent sections. The resulting atlases of human hippocampi in our recent study are further supported by gene expression patterns in each subfield and thus will provide a very helpful guide for hippocampal and subicular segmentation on neuroimaging scans. A comparison of our recent results with those in previous studies is also discussed.