Altered global brain signal in schizophrenia

Area of Science:

• Neuroscience
• Psychiatry
• Computational Biology

Background:

• Schizophrenia involves complex neurobiology and distributed brain dysfunction.
• The role of the global brain signal (GS) in schizophrenia remains unexplored.
• GS is often disregarded as a baseline in functional MRI studies.

Purpose of the Study:

• To investigate alterations in the global brain signal (GS) in schizophrenia.
• To determine the diagnostic specificity of these GS alterations.
• To explore the neurobiological underpinnings of observed GS changes.

Main Methods:

• Analysis of functional MRI data from large cohorts of schizophrenia patients, bipolar disorder patients, and healthy controls.
• Quantification of cortical power and variance, and voxel-wise signal variance.
• Biologically informed computational modeling of brain signal propagation.

Main Results:

• Schizophrenia exhibits significantly increased cortical power and variance compared to controls and bipolar disorder patients.
• Increased voxel-wise signal variance in schizophrenia was independent of GS effects.
• These alterations were specific to schizophrenia and not observed in bipolar disorder patients.
• GS removal obscured some schizophrenia-related findings.

Conclusions:

• Altered global brain signal (GS) characteristics, including increased cortical power and variance, are present in schizophrenia.
• These findings are diagnostically specific to schizophrenia.
• Computational modeling suggests altered net brain connectivity strength may explain these observations.