Reduced Laterality as a Trait Marker ofSchizophrenia—Evidence from Structural and Functional Neuroimaging

Abstract

Laterality is a characteristic principle of the organization of the brain systems for language, and reduced hemispheric asymmetry has been considered a risk factor for schizophrenia. Here we sought support for the risk factor hypothesis by investigating whether reduced asymmetry of temporal lobe structure and function is also present in unaffected relatives. Sixteen schizophrenia patients, 16 age-matched first-degree relatives, and 15 healthy controls underwent high-resolution three-dimensional anatomical imaging and functional magnetic resonance imaging during auditory stimulation. Both the overall auditory cortex and planum temporale volumes and the lateralization to the left hemisphere were markedly reduced in patients. The decrease of lateralization correlated with increased severity of symptoms. In addition, both the overall functional activation in response to auditory stimulation and its asymmetry were reduced in the patients. Relatives had intermediate values between patients and controls on both structural and functional measures. This study provides added support for the idea that reduced hemispheric asymmetry is a biological risk factor for schizophrenia.

Psychotic-like symptoms and positive schizotypy are associated with mixed and ambiguous handedness in an adolescent community sample

“…In our study, Annett's 7-way right-handers with strong/moderate left tendencies (i.e., mixed handed) were more psychosis-prone than pure right-handed subjects. These findings can be interpreted as being consistent with the hypothesized role of disrupted lateralization in the etiology of schizophrenia (e.g., Crow, 1990, Sommer et al, 2001, Schiffman et al, 2005and Oertel et al, 2010 and as a genetic risk marker for the disorder (e.g., Altamura et al, 2012).…”

Hemispheric lateralization abnormalities of the white matter microstructure in patients with schizophrenia and bipolar disorder

“…We hypothesized lateral ization abnormalities in the white matter tracts of the lan guage networks, which are functionally abnormal across psychot ic disorders 24,38 (i.e., the fronto-temporal-occipital as sociational fibres), 39 as well as subcortical regions of the exter nal capsule and posterior limb of the internal capsule, which were shown to be attenuated in a dedicated study of white matter lateralization in patients with schizophrenia. 12 Second, based on findings of left hemispheric abnormalities in a meta analysis of voxelbased studies of schizophrenia, 40 the earlier lesion and functional findings of preferential left hemispheric dysfunction in patients with schizophrenia and preferential right hemispheric dysfunction in patients with BD, 6 which were echoed in more recent neuroimaging studies of first degree relatives of patients with schizophrenia 41 and BD, 42 we hypothesized differential patterns in white matter hemi spheric lateralization abnormalities in patients with these dis orders. Third, we hypothesized an association between white matter lateralization abnormalities and the severity of psycho pathology in patients with schizophrenia and BD.…”

Associations of Cortical Thickness and Cognition in Patients With Schizophrenia and Healthy Controls

“…95,96 In patients with schizophrenia as well as their unaffected relatives, decreased or reversed anatomical asymmetry, in particular in the temporal lobe, has been reported. 15,97,98 This has been interpreted as evidence for an (epi-)genetically disturbed lateralization during neurodevelopment and as a common origin of psychosis and language-related cognitive symptoms in schizophrenia. 99,100 Further substantiating this hypothesis in the present study, verbal processing in schizophrenia patients was associated with cortical thickness in the right frontal lobe and right superior temporal gyrus, whereas we did not find any associations with this measure in HCs.…”