Understanding age-related changes in neuro-network connectivity using functional neuroimaging.

This collaborative project proposes to investigate functional and structural neural networks that are sensitive to age-related changes. Findings from the current project will provide direction in targeting the relevant networks as plausible neuroimaging markers to modulate with cognitive training and hopefully prevent normal cognitive decline. To accomplish this, we have started to establish a sensitive protocol to measure cognitive changes of clinical significance in ageing in Japan and Singapore. The current proposal aimed to continue to develop and implement a standard neuroimaging protocol applicable to both Singapore and Japan in order to maximize our data collection, as well as conduct possible cross-cultural aging studies. Due to the high costs of neuroimaging research in Singapore, we will harness the data collected from young and older adults in previous collaborations, and further evaluate the correlation among three indices of neurocognitive performance, functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI). Of particular interest, we will expand our investigations into evaluating the relationships between the resting-state and task networks of Salience and Executive Control networks. Previous neuroimaging studies have indicated age-related changes in task-induced deactivations known as the default mode network(DMN). The observed changes were thought to represent neuro-compensation due to cognitive decline in aging. However, it is not clear how the age-related changes in the DMN relate to task performance. Recent neuroimaging research has further delineated two distinguishable networks related to task-activated networks: (1) Salience and (2) Executive Control. These networks are thought to be related to task awareness and performance effort. Therefore, the task-activated networks are thought to be more sensitive candidate networks to further understand cognitive decline in relation to task performance in healthy ageing. However, the dynamics between these networks in ageing is not well understood. To further investigate age-related neuro-networks changes, we will study the relationships between task-induced deactivations, resting-state networks, and structural connectivity in the healthy aging brain. We will then apply cognitive training to both elderly and young adults in a pilot study to investigate possible modulations of age-related neural substrates.

Project Objectives

1. Characterize age-related changes in functional networks of DMN, salience and executive function for task and resting-state fMRI.

2. Evaluate age-related effects on functional connectivity within these networks between task and resting-state fMRI.

3. Evaluate age-related effects structural connectivity and white matter integrity within the identified networks using DTI.

4. Integration of both functional and structural connectivity networks.

5. Conduct a pilot study to see how working memory training (Singapore site) and fine motor training? (Japan site) will affect these networks