Effective connectivity within the corticothalamic circuit in the neuromyelitis optica patients: A comparative study...

Neuromyelitis Optica, which is known as NMO, is a demyelination syndrome and inflammatory condition of the central nervous system that affects the optic nerves. Since structural imaging approaches cannot adequately describe the brain disorders in patients with NMO, functional magnetic resonance imaging (fMRI) can be used. Resting-state fMRI was performed on 25 healthy subjects and 26 NMO patients. After preprocessing the data, the time series belonging to the regions of the middle frontal gyrus (MFG), inferior frontal gyrus (IFG), precuneus (PRE), thalamus (THA), and middle temporal gyrus (MTG) were extracted as components of the corticothalamic circuit. The obtained time series were statistically analyzed as the input of dynamic causal modeling (DCM) in order to evaluate the effective connectivity within the corticothalamic circuit. The statistical analyses showed that the mean of effective connectivity power was significantly higher in the healthy subjects than in the NMO patients. For the healthy subjects, there was no significant difference in effective connectivity power between the two groups of males and females at the significance level of 0.05. In the NMO patients, there was a significant difference between the effective connectivity levels of the male and female groups only for IFG → MFG, in which it was greater in males than in females. The results of our studies showed that resting-state fMRI could exhibit the difference between healthy and NMO subjects.