ABSTRACT
Background and Purpose
Amygdala dysfunction is implicated in major depressive disorder. Despite wide acknowledgement of its heterogeneity, the amygdala is predominantly considered as a single entity and functional connectivity investigations have reported findings using standard or low spatial resolution functional MRI data. This study compared the capabilities of two high spatial resolution acquisition strategies, the gold standard 2D and a novel 3D, in identifying amygdala functional connectivity to other brain regions at a subregional level.
Methods
Resting state fMRI data were acquired at 3T in 10 healthy controls using both versions of a Gradient-Echo Echo Planar Imaging (GRE-EPI) sequence. Whole brain voxel-wise functional connectivity measures were calculated using the whole amygdala and six subregional seed regions-of-interest; left and right basolateral, centromedial and superficial.
Results
The 3D data identified multiple stronger bilateral connections between both centromedial subregions, most notably to subcortical structures including brainstem and hippocampus, as well as intra-amygdala subregional connections. The 2D data displayed stronger connections to several cortical regions. Whole amygdala and subregional FC results differed.
Conclusions
This study identified underutilized capability in current fMRI acquisition techniques at 3T. 2D GRE-EPI sequences optimized for high spatial resolution with voxel volumes of 15.6 mm3 capably demonstrate functional connectivity patterns of the amygdala at a subregional level, allowing interrogation of heterogeneous amygdala function at a more granular level. The novel 3D acquisition with voxel volumes of 8 mm3 showed promise in outperforming its 2D counterpart in identifying amygdala subregional connections to other subcortical structures that are traditionally difficult to image well.
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This post is Copyright: Sheryl L. Foster,
Ramon Landin‐Romero,
Sarah Lewis,
Mayuresh S. Korgaonkar | December 17, 2025
Wiley: Journal of Neuroimaging: Table of Contents