Spatial patterns of intrinsic neural activity in depressed patients with vascular risk factors as revealed by the amplitude of low-frequency fluctuation.

To investigate spatial patterns of intrinsic neural activity of depressed patients with vascular risk factors using resting-state functional magnetic resonance imaging (fMRI) and to examine the relationship between regional activity abnormalities and symptom severity factor, we analyzed spatial patterns of spontaneous brain activity in 19 depressed patients with vascular risk factors and 18 healthy subjects. Intrinsic brain activity was measured by the amplitude of low-frequency fluctuations (ALFF) of the resting-state blood oxygen level dependent signal. Depressed patients with vascular risk factors showed decrease in ALFF in the limbic-cortical-striatal-pallidal-thalamic circuit. Specifically, the altered ALFF values (i.e., left insula and right superior frontal gyrus) were significantly correlated with depression severity in the depressed group. In addition, higher ALFF values in the right middle temporal gyrus and right superior temporal gyrus were observed in depressed patients with vascular risk factors. Our findings reveal distinct functional patterns of abnormal brain activity in depressed patients with vascular risk factors and have implications for the understanding of the pathophysiology of this understudied population.