Cerebral Correlates of the Activation of the Cardiovascular Autonomic Nervous System – An FDG-PET Study

Abstract

Background: Visual self-motion perception is induced by large-field visual motion stimulation (circular vection, CV). The stationary observer perceives the surroundings as being stable and himself as being moved. This stimulus provides profound activation, in particular, of the sympathetic nervous system (arousal reaction) Our fluorodeoxyglucose (FDG)-PET study focused on those brain areas that are involved in the processing of autonomic changes during CV. Correlation analyses were performed between metabolic effects and autonomic parameters during visual motion stimulation. Methods: FDG-PET (Siemens, Germany) was performed in 14 healthy subjects (8 male, 7 female; mean age 29.5 years) during CV induced by a computer-animated coherent dot pattern moving clockwise, or a random dot pattern of the same size. Correlation analyses with different parameters for autonomic cardiovascular control (blood pressure, heart rate variability, blood pressure and plasma catecholamines) were performed with the SPM99b software (threshold for significant activation was set at p<0.001, uncorrected). Results: Significant positive correlations were found between the high frequency spectrum of heart rate variability and activations in the anterior cingulate gyrus (BA 6) and nucleus caudatus.. Low frequency heart rate variability correlates either with activations in the anterior cingulate and the amygdala bilaterally. Deactivation in the caudate nucleus significantly correlated to frequency changes of heart rate and levels of plasma catecholamines. Conclusion: Our study showed that arousal reaction activates and deactivates a network of „autonomic“ brain areas. Obviously the limbic cortex and the basal ganglia are the most important to control cardiovascular function.