Amygdala and emotionality in Parkinson's disease: An integrative review of the neuropsychological evidence.

Parkinson's disease (PD) is often accompanied by significant changes in emotionality, such as apathy, anhedonia, anxiety and depression. The present review summarizes the empirical evidence, including amygdala changes and psychological changes in emotionality in people suffering from PD. Seventeen empirical full-text articles including research on both amygdala and emotionality in PD were reviewed. The changes in amygdala volumes as well as changes in binding potentials, functional connectivity, regional homogeneity and regional cerebral blood flow were found to have various impacts on emotionality in people with PD. The integration of the results showed that some effects of amygdala changes on emotionality were lateralized. Some of the reviewed studies indicated that the volume loss in the left amygdala was found to be related to increased anxiety, whereas bilateral volume loss in amygdala was linked to increased depressivity. The reviewed results also support a hypothesis of bradylimbic affective disturbance in patients with PD. The disturbed activation of amygdala accompanying the evaluation of negative facial expressions implies that the evaluation of the content of affective stimuli in terms of their affective meanings is disturbed in PD patients. Impaired evaluation of affective attributes given by amygdala-based translational deficits is likely to be related to problems in translating the results of cognitive appraisal into somatomotor, arousal and other changes. This mechanism is suggested to be responsible for apathy as well as for other changes in emotionality accompanying PD.