University of Florida Center for Movement Disorders & Neurorestoration graduate student Jenna Dietz studied the pupils, and also eye movements in Parkinson’s disease patients. Jenna, a member of the Bower’s lab published her findings in Neuropsychologia. Interestingly eye movements, but not pupil responses were impaired in the Parkinson’s group while viewing pictures designed to elicit different emotions.
Emotion and ocular responses in Parkinson’s disease.
Parkinson’s disease (PD) is a neurodegenerative disease that affects motor, cognitive, and emotional functioning. Previous studies reported reduced skin conductance responses in PD patients, compared to healthy older adults when viewing emotionally arousing pictures. Attenuated skin conductance changes in PD may reflect peripheral autonomic dysfunction (e.g., reduced nerve endings at the sweat gland) or, alternatively, a more central emotional deficit. The aim of the current study was to investigate a second measure of sympathetic arousal-change in pupil dilation. Eye movements, a motor-based correlate of emotional processing, were also assessed. Results indicated that pupil dilation was significantly greater when viewing emotional, compared to neutral pictures for both PD patients and controls. On the other hand, PD patients made fewer fixations with shorter scan paths, particularly when viewing pleasant pictures. These results suggest that PD patients show normal sympathetic arousal to affective stimuli (indexed by pupil diameter), but differences in motor correlates of emotion (eye movements).