The diminished interhemispheric connectivity correlates with negative symptoms and cognitive impairment in first-episode schizophrenia.

BACKGROUND: Previous studies imply that interhemispheric disconnectivity plays a more important role on information processing in schizophrenia. However, the role of the aberrant interhemispheric connection in the pathophysiology of this disorder remains unclear. Recently, resting-state functional Magnetic Resonance Imaging (fMRI) has reported to have potentials of mapping functional interactions between pairs of brain hemispheres.

METHODS: Resting-state whole-brain functional connectivity analyses were performed on 41 schizophrenia patients and 33 healthy controls.

RESULTS: The first-episode schizophrenia patients showed significant aberrant interhemispheric connection in the globus pallidus, medial frontal gyrus and inferior temporal gyrus. The correlation of Wechsler Adult Intelligence Scale scores with odds ratio of the aberrant interhemispheric connections revealed positive correlation in the pallidum (rho=0.335, p=.003) and medial frontal gyrus (rho=0.260, p=.025). The connection in the pallidum was also positively correlated with duration of illness (rho=-0.407, p=.009). Whereas, the aberrant interhemispheric connection in the inferior temporal gyrus was positively correlated with scores of Scale for the Assessment of Negative Symptoms (rho=0.393, p=.012).

CONCLUSION: The present study provides fMRI evidence for the aberrant interhemispheric resting-state functional connectivity within resting-state networks in first-episode schizophrenia patients. These aberrant interhemispheric connections, in particular the pallidum, due to its anatomical and functional connectivities, may be the primary disturbance for cognitive impairment, negative symptoms and chronicity of schizophrenia.