Cerebral regional and network abnormalities in HIV-infected with neurocognitive impairments: An fMRI study

Although the combination antiretroviral treatment (cART) has considerably lowered the risk of HIV associated dementia (HAD), the incidence of neurocognitive impairments(NCI) have not decreased likely due to the insidious and slow progressive nature of HIV infection. Recent studies show that the rest state functional magnetic resonance imaging (rs-fMRI) is a prominent technique in helping the non-invasive analysis of neucognitive impairment. Our study is to explore the neuroimaging characteristics among people living with HIV(PLW-HIV) with or without NCI in terms of cerebral regional and neural network by rs-fMRI, based on the hypothesis that HIV patients with and without NCI have independent brain imaging characteristics. 33 HIV subjects with NCI and 33 HIV subjects without NCI, classified into HIV-NCI group and HIV-control group respectively according to Mini-Mental State Examination(MMSE) results. The fraction amplitude of low-frequency fluctuation (fALFF) and functional connectivity (FC) were calculated to characterize the cerebral regional and neural network alterations. Finally, the correlation among fALFF/FC values in certain cerebral regions and clinical characteristics were calculated. Compared to the HIV-control group, the fALFF values of bilateral calcarine gyrus, bilateral superior occipital gyrus, left middle occipital gyrus, left cuneus in the HIV-NCI group were increased. The FC values between right superior occipital gyrus and right olfactory cortex, bilateral gyrus rectus, right orbital part of middle frontal gyrus in the HIV-NCI group were increased. The FC values between left hippocampus and bilateral medial prefrontal gyrus, bilateral superior frontal gyrus were decreased. The fALFF values of left cuneus in both two groups was negatively correlated with international HIV dementia scale scores (IHDS) (R=-0.255, P=0.037) ; The fALFF values of left calcarine gyrus in both two groups was negatively correlated with MMSE scores (R=-0.316, P=0.009) ; The FC values between right superior occipital gyrus and right olfactory cortex (R=-0.396, P=0.001) in both two groups was negatively correlated with MMSE scores. Our study showed that the abnormal fMRI patterns in specific brain regions of the occipital cortex, while the defects in brain network mostly associated with prefrontal cortex, were associated with HIV-related cognitive impairment. The variation of fALFF and FC in given brain regions can be used to distinguish HIV subjects with and without cognitive impairment.