Poster D58, Monday, March 26, 8:00-10:00 am, Exhibit Hall C
Reward learning in pre-symptomatic and symptomatic Huntington’s disease
Madeleine Sharp1, Karen Marder2, Daphna Shohamy3; 1McGill University, 2Columbia University Medical Center, 3Columbia University
Striatal neurons are the earliest target of Huntington’s disease and neuroimaging studies in humans have confirmed that striatal atrophy is detectable even in the earliest stages of the disease. This early, or pre-symptomatic stage of Huntington’s disease is also characterized by subtle behavioural changes, but attempts to track early disease progression with behaviour have been largely unsuccessful, probably owing to the fact that the clinical scales used to measure behaviour and cognition are often non-specific. Remarkably, despite the extensive literature demonstrating the crucial role of the striatum in signalling reward, to our knowledge no studies have investigated specific striatum-dependent cognitive processes in patients with Huntington’s disease. Here we aimed to address this gap by measuring reward learning in pre-symptomatic Huntington’s patients, symptomatic patients and healthy controls. As expected, results show that learning rate and overall performance are impaired in symptomatic Huntington’s patients but importantly, that they are also impaired, though to a lesser degree, in pre-symptomatic patients. These findings suggest that reward learning could be used as a marker of disease, even in the earliest stages. Ongoing work aims to determine whether reduced reward learning represents a cognitive mechanism underlying early behavioural symptoms such as apathy.
Topic Area: LONG-TERM MEMORY: Development & aging