Objective: Anxiety and chronic stress are common symptoms of Parkinson's disease (PD) influencing the quality of life. To identify brain regions associated with these symptoms we compared resting brain connectivity to actual anxiety and to the cortisol awakening response.
Participants and methods: Using the resting state-fMRI (3 T, TR = 2 s, 300 scans) we analyzed spontaneous low frequency blood oxygenation-level dependent signal fluctuations in 25 PD patients (66.7 ± (SD)7.4 years) in their OFF and ON medication states. The State-Trait Anxiety Inventory (STAI) was used to assess the severity of anxiety immediately before each fMRI session. Cortisol salivary levels were measured at awakening and 30, 60 and 90 min later. We calculated the area under the curve with respect to the ground (AUCg). To evaluate brain connectivity we used Eigenvector centrality (EC) mapping, which automatically detects all brain areas serving as strong communication hubs.
Results: The STAI state anxiety increased during OFF compared to ON condition (p < 0.01) and positively correlated with the EC values in the dorsal part of the right ventromedial prefrontal cortex (VMPFC) and in both caudates (P < 0.05 corrected). Cortisol salivary levels did not change significantly between the sessions, however, the AUCg showed a negative correlation with EC values in the ventral part of the VMPFC.
Conclusions: The state anxiety and the cortisol awakening response during OFF and ON sessions are accompanied by inverse changes of the functional connectivity in the distinct regions of the VMPFC network. Supported by IGA-NT12282-5-2011; PRVOUK-P26/LF1/4.
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© 2015 Published by Elsevier Inc.
