Emotional valence may influence memory performance for visual artworks in Parkinson’s disease

Background: Non-motor symptoms in Parkinson’s disease (PD) include reduced reactivity to emotional stimuli. Visual artworks can evoke emotional responses. Motor, sensorial and cognitive networks implicated in the aesthetic experience and in the emotional-reward domain show a significant overlap with the pathological nigrostriatal, mesocortical and mesolimbic circuitry that characterises PD. Methods: Memory enhancement by emotional stimuli such as visual artwork-stimuli was explored in 12 right-sided and 12 left-sided non-demented-PD patients, 12 Alzheimer’s disease patients (AD) and 13 healthy controls (HC). Ten emotional and 10 non-emotional stimuli were previously identified based on the ratings of the emotional impact provided by 45 non-PD subjects on 82 pictures of paintings. Only figurative artworks were included. Patients and HC were requested to rate on a 7-point scale the emotional impact of 20 pictures; they were then requested to recognise the 20 pictures amongst 20 distractors (incidental memory task). Results and Conclusion: Recognition of emotional stimuli was more accurate compared to non-emotional stimuli in AD, left-sided PD and HC; right-sided PD did not show sensitivity to the emotional valence of the stimuli suggesting the involvement of the nigrostriatal, mesocortical and mesolimbic circuitry of the left hemisphere in the emotional-reward system related to the aesthetic experience.