Alzheimer’s disease affects at least 13% of the population over age 65. Because early detection may lead to opportunities for early intervention, recent research has focused on understanding patients with Mild Cognitive Impairment (MCI), a syndrome diagnosed when a patient presents with a memory complaint, but does not show impairments in functional abilities. Although not all patients with MCI develop AD, all patients with AD pass through a MCI stage, and it is estimated that 12% convert to AD each year.
Functional magnetic resonance imaging (fMRI) allows for the examination of brain functioning while a patient is performing a cognitive task. This technique is especially well suited to identifying changes in brain functioning before significant impairments can be detected on standard neuropsychological tests, and as such is sensitive to early identification of disease processes. Although recent fMRI work has been used to characterize MCI, this work has primarily focused on understanding the neural changes underlying memory dysfunction, with emphasis on the medial temporal lobe (MTL). MCI patients may present with subtle declines in other realms of cognition, including executive functioning (EF), and EF deficits are directly associated with progression from MCI to AD. Moreover, worsening EF is associated with poorer functional abilities, and loss of independent functioning is a key criterion distinguishing MCI from AD. As such, understanding the neural circuitry underlying EF in MCI has the potential to reveal novel information regarding degenerative changes associated with illness progression.
The primary goal of the research proposed here is to examine the neural underpinnings of EF in MCI. This will include investigation of how structural and functional brain changes may interact to result in EF deficits, and their association with disease severity and disease progression. This work aims to highlight the importance of regions outside of the MTL in MCI neuropathology.