A preliminary evaluation of the correlation between regional energy phosphates and resting state functional connectivity in depression.

Impaired brain energy metabolism is among the leading hypotheses in the pathogenesis of affective disorders and linking energy phosphates with states of tissue-function activity is a novel and non-invasive approach to differentiate healthy from unhealthy states. Resting state functional MRI (fMRI) has been established as an important tool for mapping cerebral regional activity and phosphorous chemical shift imaging ((31)P CSI) has been applied to measure levels of energy phosphates and phospholipids non-invasively in order to gain insight into the possible etiology of affective disorders. This is an initial attempt to identify the existence of a correlation between regional energy phosphates and connectivity at nodes of the posterior default mode network (DMN). Resting state fMRI in conjunction with (31)P 2D CSI was applied to 11 healthy controls and 11 depressed patients at 3 T. We found that differences between the two groups exist in correlation of lateral posterior parietal cortex functional connectivity and regional Pi/PCr. Results of this study indicate that resting-state-fMRI-guided (31)P CSI can provide new insight into depression via regional energy phosphates and functional connectivity.