title: Abnormal asymmetry of brain connectivity in schizophrenia.
abstract: Recently, a growing body of data has revealed that beyond a dysfunction of connectivity among different brain areas in schizophrenia patients (SCZ), there is also an abnormal asymmetry of functional connectivity compared with healthy subjects. The loss of the cerebral torque and the abnormalities of gyrification, with an increased or more complex cortical folding in the right hemisphere may provide an anatomical basis for such aberrant connectivity in SCZ. Furthermore, diffusion tensor imaging studies have shown a significant reduction of leftward asymmetry in some key white-matter tracts in SCZ. In this paper, we review the studies that investigated both structural brain asymmetry and asymmetry of functional connectivity in healthy subjects and SCZ. From an analysis of the existing literature on this topic, we can hypothesize an overall generally attenuated asymmetry of functional connectivity in SCZ compared to healthy controls. Such attenuated asymmetry increases with the duration of the disease and correlates with psychotic symptoms. Finally, we hypothesize that structural deficits across the corpus callosum may contribute to the abnormal asymmetry of intra-hemispheric connectivity in schizophrenia.
authors.affiliation: Dipartimento di Medicina dei Sistemi, Clinica Psichiatrica, Università di Roma Tor Vergata , Rome , Italy ; Laboratorio di Neurologia Clinica e Comportamentale, Fondazione Santa Lucia IRCCS , Rome , Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Ribolsi
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, University of Toronto , Toronto, ON , Canada.
authors.forename: Zafiris J
authors.initials: ZJ
authors.lastname: Daskalakis
authors.affiliation: Dipartimento di Medicina dei Sistemi, Clinica Psichiatrica, Università di Roma Tor Vergata , Rome , Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Siracusano
authors.affiliation: Laboratorio di Neurologia Clinica e Comportamentale, Fondazione Santa Lucia IRCCS , Rome , Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Koch
keywords: asymmetry; connectivity; diffusion tensor imaging; fMRI; interhemispheric; schizophrenia