Frontiers in Neuroscience (Aug 2023)

Fine scale hippocampus morphology variation cross 552 healthy subjects from age 20 to 80

  • Qinzhu Yang,
  • Shuxiu Cai,
  • Guojing Chen,
  • Xiaxia Yu,
  • Renee F. Cattell,
  • Renee F. Cattell,
  • Tammy Riklin Raviv,
  • Chuan Huang,
  • Chuan Huang,
  • Nu Zhang,
  • Yi Gao,
  • Yi Gao,
  • Yi Gao

DOI
https://doi.org/10.3389/fnins.2023.1162096
Journal volume & issue
Vol. 17

Abstract

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The cerebral cortex varies over the course of a person's life span: at birth, the surface is smooth, before becoming more bumpy (deeper sulci and thicker gyri) in middle age, and thinner in senior years. In this work, a similar phenomenon was observed on the hippocampus. It was previously believed the fine-scale morphology of the hippocampus could only be extracted only with high field scanners (7T, 9.4T); however, recent studies show that regular 3T MR scanners can be sufficient for this purpose. This finding opens the door for the study of fine hippocampal morphometry for a large amount of clinical data. In particular, a characteristic bumpy and subtle feature on the inferior aspect of the hippocampus, which we refer to as hippocampal dentation, presents a dramatic degree of variability between individuals from very smooth to highly dentated. In this report, we propose a combined method joining deep learning and sub-pixel level set evolution to efficiently obtain fine-scale hippocampal segmentation on 552 healthy subjects. Through non-linear dentation extraction and fitting, we reveal that the bumpiness of the inferior surface of the human hippocampus has a clear temporal trend. It is bumpiest between 40 and 50 years old. This observation should be aligned with neurodevelopmental and aging stages.

Keywords