id_933. AMYGDALA, BUT WHICH ONE? A COMPARATIVE ANALYSIS OF DIFFERENT AMYGDALA MASKS
Sylwia Adamus1, Małgorzata Draps2, Piotr Suffczyński3
1 Infant Jesus Teaching Hospital, 4 Williama Heerleina Lindleya St., Warsaw, Poland
2 Polish Academy of Sciences, Institute of Psychology, Lab of Clinical Neuroscience, 1 Jaracza St., Warsaw, Poland
3 University of Warsaw, Faculty of Physics, Biomedical Physics Division, 5 Pasteura St., Warsaw, Poland
INTRODUCTION: The amygdala is a paired, subcortical structure which plays a role in multiple processes related to emotional processing. Its neuroimaging in vivo is a major challenge due to its small size and complex internal structure. As a result, there is a vast variety of masks which can be used to define its boundaries. This has been a major drawback in studies regarding amygdala’s volume alterations.
AIM(S): The aim of this study was to compare different amygdala masks on the level of the unparcellated structure, as well as its subparts.
METHOD(S): Resting-state functional magnetic resonance imaging data from 155 healthy individuals with no underlying neurological or psychiatric conditions was acquired from the OpenNeuro repository. The data was preprocessed and denoised using CONN Functional Connectivity Toolbox and a group-level resting-state functional connectivity (rs-FC) analysis was conducted for three different amygdala masks. Next, a parcellation pipeline was applied to the blood oxygen level dependent signal of the voxels within the amygdala as defined by each of the masks.
RESULTS: The rs-FC analysis showed that despite multiple connections present regardless of the used mask, connections with several brain regions were unique to particular masks. This was most prominent for the left amygdala when defined with the mask by Dominik Bach et al (2011), compared to a popular mask of similar size from the Harvard-Oxford atlas. The amygdalae were divided into two subdivisions - the dorsomedial (DM) and the ventrolateral (VL). For the Bach mask the DM/VL size ratio was remarkably smaller for both amygdalae compared to other masks.
CONCLUSIONS: To conclude, even small changes in the size and spatial position of the chosen amygdala mask can result in markedly different patterns of rs-FC and internal structure. As the amygdala is known to be involved in the development of multiple mental health conditions, this might provide an explanation why many studies in clinical groups have failed to obtain consistent results.
FINANCIAL SUPPORT: Not applicable