Decreased Spontaneous Low-frequency BOLD Signal Fluctuation in First-episode Treatment-naive Schizophrenia *

The default mode of brain function hypothesis has been readdressed from the perspective of the presence of low-frequency blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signal changes (0.01-0.1Hz) in the resting healthy brain. In this study, a newly reported cosine- statistical parameter mapping (SPM) approach is presented to measure the temporal low-frequency blood oxygenation level-dependent (BOLD) signal for exploring the brain activity of schizophrenia in a resting state with subjects' eyes closed. Firstly, the nine cosine functions with frequency between 0.01and 0.1Hz are specified as the design matrix of the general linear model, then fMRI data is analyzed by SPM method. Nine first-episode treatment-naive schizophrenia patients and nine healthy subjects participated in this study. The results showed diminished low-frequency spontaneously activity in schizophrenia.