Project - Amygdala integrity in frontotemporal dementia
This project aims to map the structural and functional changes of the amygdala and its network across frontotemporal dementia subtypes, and their relations to emotion processing and social cognition.
This project is supported by Australian Government RTP Scholarship (2021-2024)
Research Project Description
Frontotemporal dementia (FTD) encompasses a group of clinical syndromes characterised by significant behavioural and/or language disturbances. Social cognition and emotion processing impairments are prominent features across FTD subtypes. Clinically, FTD patients tend to show difficulties with understanding other people’s state of mind, as well as with expressing and recognising emotions in others. Consistent neuroimaging evidence has demonstrated that these deficits are closely associated with atrophy in a number of brain regions including the amygdala, a core structure located in the temporal lobe. The amygdala is known to play a central role in regulating emotional and social cognitive processes. Importantly, it comprises a number of nuclei that are extensively interconnected with a wide range of cortical and subcortical brain structures (e.g., orbitofrontal and anterior temporal cortices, insula, hippocampus). Despite its critical role in integrating emotional and cognitive processes, few studies have attempted to examine amygdala pathology in FTD, and most of which only considered it as a single structure rather than a constellation of nuclei that are associated with distinct connections and functions.
In order to address this gap in current research, this multi-modal imaging project moves away from the traditional approach of examining the amygdala as a homogenous structure, comprehensively investigates the changes in amygdala networks in FTD and their relations to presenting symptoms, taking also its nuclei-specific connections into account. The outcomes of this project will inform our understanding of how the amygdala-associated networks are affected in different variants of FTD, establish trajectories of progression in amygdala nuclei over the course of FTD and provide important information about the clinical profiles of FTD.
The aim of this project is to investigate to what extent the amygdala nuclei and their associated networks are affected across the different forms of FTD (behavioural variant FTD, semantic dementia, progressive nonfluent aphasia) as compared to healthy elderly controls and AD patients. The specific objectives of this project are to:
- a) Characterise changes in amygdala nuclei volume as well as structural and functional connectivity of the associated networks across FTD subtypes
- b) Examine the correlation between changes in amygdala nuclei and performance in emotion processing and social cognition tasks
- c) Identify the common and disease-specific changes in amygdala in bvFTD and AD, compared with healthy controls
- d) Establish trajectories of progression in the amygdala nuclei and associated networks over the course of FTD through longitudinal analyses.
Participants completed comprehensive cognitive, emotion processing, social cognition and neuroimaging measures. Structural magnetic resonance imaging (MRI) data are processed using FreeSurfer to assess grey matter volume of the whole amygdala and the nuclei. Diffusion tensor imaging (DTI) data are processed by MRtrix3 to investigate changes in white matter microstructure within amygdala-associated networks. Resting state functional MRI data are processed by FSL FMRI Expert Analysis Tool (FEAT) to examine the functional connectivity of amygdala-associated networks.