A perfusion MRI study of emotional valence and arousal in Parkinson's disease

Abstract

Background. Brain regions subserving emotion have mostly been studied using functional magnetic resonance imaging (fMRI) during emotion provocation procedures in healthy participants. Objective. To identify neuroanatomical regions associated with spontaneous changes in emotional state over time. Methods. Self-rated emotional valence and arousal scores, and regional cerebral blood flow (rCBF) measured by perfusion MRI, were measured 4 or 8 times spanning at least 2 weeks in each of 21 subjects with Parkinson's disease (PD). A random-effects SPM analysis, corrected for multiple comparisons, identified significant clusters of contiguous voxels in which rCBF varied with valence or arousal. Results. Emotional valence correlated positively with rCBF in several brain regions, including medial globus pallidus, orbital prefrontal cortex (PFC), and white matter near putamen, thalamus, insula, and medial PFC. Valence correlated negatively with rCBF in striatum, subgenual cingulate cortex, ventrolateral PFC, and precuneus-posterior cingulate cortex (PCC). Arousal correlated positively with rCBF in clusters including claustrum-thalamus-ventral striatum and inferior parietal lobule and correlated negatively in clusters including posterior insula-mediodorsal thalamus and midbrain. Conclusion. This study demonstrates that the temporal stability of perfusion MRI allows within-subject investigations of spontaneous fluctuations in mental state, such as mood, over relatively long-time intervals.

Figure 1

Score of visual analog scale on circumplex model of emotion. The 4 diameters shown represent the 8 pairs of adjectives used for the VAS items that generated the valence and arousal scores. The short perpendicular mark on each diameter represents the mean value for the corresponding VAS items in this sample.

Figure 2

Statistical parametric (T) maps for correlations with valence. (a–c) Positive correlation with valence in (a) right putamen (22.5, 15, 6); (b) right medial globus pallidus (16.5, −3, −3); (c) right middle frontal gyrus (28.5, 42, −9) (BA 11). (d–f) Negative correlation with valence in (d) right subcallosal gyrus (4.5, 24, −15) (BA25); (e) left caudate (−13.5, 12, 3); (f) right inferior frontal gyrus (38, 27, 0) (BA47).

Figure 3

Statistical parametric (T) maps for correlations with arousal. (a) Positive correlation with arousal in right putamen (28.5, 6, 0). (b) Negative correlation with arousal in left amygdala-striatal transition area (−25.5, −6, −9).