Objective: Higher mental functions depend on global cerebral functional coordination. Our aim was to study fast
modulation of functional networks in schizophrenia that has not been previously assessed.
Methods: Graph-theory was used to analyze the electroencephalographic (EEG) activity during an odd-ball task
in 57 schizophrenia patients (18 first episode patients, FEPs) and 59 healthy controls. Clustering coefficient
(CLC), characteristic path length (PL) and small-worldness (SW) were computed at baseline ([−300 0] ms prior
to stimulus delivery) and response ([150 450] ms post-stimulus) windows. Clinical and cognitive assessments
were performed.
Results: CLC, PL and SW showed a significant modulation between baseline and response in controls but not in
patients. Patients obtained higher CLC and SW at baseline, lower CLC and higher PL at response, and diminished
modulation of CLC and SW as compared to controls. In patients, CLC and SW modulation were inversely
associated to cognitive performance in executive tasks and directly associated to working memory. Similar
patterns were observed in FEPs. CLC and SW during the baseline were inversely associated to their respective
modulation magnitudes.
Conclusions: Our results are coherent with a hyper-segregated network at baseline (higher CLC) and a decreased
modulation of the functional connectivity during cognition in schizophrenia.
