Functional connectivity of the left and right hippocampi: Evidence for functional lateralization along the long-axis using meta-analytic approaches and ultra-high field functional neuroimaging

Neuroimage. 2016 Jul 15;135:64-78. doi: 10.1016/j.neuroimage.2016.04.022. Epub 2016 Apr 27.

Abstract

Theories regarding the functional specialization of the hippocampus date back to over a century ago. Two main theories have dominated the field. First, evidence has supported the notion of hemispheric specialization, which appears to be preserved across species. Second, an emergent and mounting set of data has suggested an anterior-posterior neurofunctional gradient. However, no study has examined these theories, and their potential interaction, using objective, robust methodological approaches. Here, we employed an established meta-analytic technique and use ultra-high field, high-resolution functional and structural neuroimaging to examine hippocampal lateralization with consideration for a long-axis differentiation. Data revealed strong support for an evolutionarily preserved hemispheric specialization. Specifically, we found intra- and interhemispheric differences with regard to anterior and posterior functional and structural connectivity, between the right and left hippocampi. For task-independent functional connectivity, we found the right anterior hippocampus to have functional connectivity with a large, distributed network, whereas the left anterior hippocampus demonstrated primarily fronto-limbic connectivity. These patterns were reversed for the posterior segmentations. Not surprisingly, for task-dependent connectivity, we found interhemispheric differences within key ipsilateral structures (i.e., parahippocampal gyrus) for both anterior and posterior segmentations. Furthermore, we identified pivotal neural hubs that share connectivity across behavioral domains, and are supported by structural connectivity (i.e., posterior cingulate cortex). Thus, our data provide evidence for a hemisphere-specific, anterior-posterior specialization of the hippocampal formation.

Keywords: 7T; BrainMap; DTI; Long-axis; MACM; fMRI.

Publication types

  • Meta-Analysis

MeSH terms

  • Brain Mapping / methods
  • Computer Simulation
  • Connectome / methods*
  • Female
  • Functional Laterality / physiology*
  • Hippocampus / anatomy & histology*
  • Hippocampus / physiology*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Models, Neurological*
  • Nerve Net / anatomy & histology
  • Nerve Net / physiology
  • Neural Pathways / anatomy & histology
  • Neural Pathways / physiology
  • Neuroimaging / methods*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Young Adult