Investigating the cognitive mechanisms underlying apathy in Huntington’s disease using a gambling task
Huntington’s Disease (HD) is a genetic neurodegenerative disease that leads to a range of progressive motor, cognitive and psychiatric deficits. Apathy is the most prevalent psychiatric symptom in HD patients, having a strong impact on their quality of file. According to neuroimaging studies, apathetic behavior may be theresult of disruptions in reward-processing areas. Even though these regions are not supposed to be damaged in early-stage HD patients, recent studies suggest a more widespread neurodegeneration. In the present study, we implemented a gambling task to investigate the functional and behavioral correlates of apathy in HD during the processing of rewards. We found that monetary losses have a greater impact in apathetic HD patients, which may be explained by disruptions in the supplementary motor area, thalamus and precentral gyrus that lead to deficits in the integration and execution of motivated behavior. We found specific alterations in part of the ventral striatum, suggesting a more widespread neurodegeneration. Furthermore, we found abnormal activity in the insula in HD manifest patients, possibly reflecting an enhanced aversion to negative events.