Dissociating Components of Anhedonia: A Pilot fMRI Study
Condition: Anhedonia
MeSH terms: Anhedonia
Study type: Interventional

Summary: 
      Anhedonia, decreased motivation for and sensitivity to rewarding experiences, is present in
      at least 1/3 of community dwelling older adults and is a feature of various psychiatric and
      neurological disorders, including late-life depression and Parkinson's disease. Anhedonia is
      associated with cognitive deficits, as well as poor clinical outcomes and increased
      mortality. Recent research suggests that anhedonia comprises motivational (reward "wanting")
      and consummatory (reward "liking") aspects. However, previous research on anhedonia has
      failed to dissociate these components, which may explain the contradictory findings in the
      literature. Recently, the Effort-Expenditure for Rewards Task (EEfRT) was developed in an
      effort to dissociate reward components in anhedonia. The EEfRT is an effort-based
      decision-making task that measures reward "wanting", in contrast to commonly used anhedonia
      questionnaires, which focus on reward "liking." This novel task may provide a useful measure
      of components of anhedonia in older adults and in different patient populations. Thus far no
      data is available on this task in elderly individuals, and the cognitive and neural
      correlates of components of the task have not been investigated. Given the paucity of
      research on the neurobiology of anhedonia, cognitive neuroscience studies using this task
      could fill a gap in the literature. The investigators are developing a line of cognitive
      neuroscience studies examining anhedonia in community-dwelling older adults and in late-life
      depression and Parkinson's disease. This study will involve gathering pilot behavioral and
      functional magnetic resonance imaging (fMRI) data in young and older adults performing the
      EEfRT task. Understanding the brain mechanisms underlying anhedonia in older adults and in
      different patient populations will have a translational impact by elucidating biological
      targets for treatment.
    

Detailed description: 
      Twenty young adults (aged 18-38) and 20 older adults (aged 60-80) will perform the EEfRT
      while fMRI data are acquired. To quantify brain activity associated with reward "wanting,"
      the fMRI activation will be measured while participants view information about reward
      probability and choose to perform the easy or hard task, with greater reward associated with
      the hard task. The investigators will measure activation during presentation of reward
      magnitude to capture brain activity associated with reward "liking." Participants will also
      complete a brief cognitive battery and anhedonia questionnaires.
    

Intervention name(s): Functional Magnetic Resonance Imaging; Effort-Expenditure for Rewards Task
Intervention type(s): Other; Other
Intervention description(s): Both groups will have the fMRI performed once. The fMRI will be use to to dissociate activity associated with both reward "wanting" and reward "liking" using the EEfRT. Learning more about the brain basis of components of anhedonia in both young and older adults is important in the context of previous research showing that risk-taking behavior and reward sensitivity changes with age, enhancing the knowledge of anhedonia.; Both groups with have the EEfRT performed once. The EEfRT is an effort-based decision-making task that measures reward "wanting", in contrast to commonly used anhedonia questionnaires, which focus on reward "liking." This novel task may provide a useful measure of components of anhedonia in older adults and in different patient populations.
Other intervention name(s): fMRI; EEfRT
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Other