Handedness, language lateralisation and anatomical asymmetry in schizophrenia

Abstract

Strong evidence is provided for decreased cerebral lateralisation in schizophrenia.

Constitutive Hyperdopaminergia is Functionally Associated with Reduced Behavioral Lateralization

“…Ambidextrousness and mixed-handedness were found to be powerful predictors of reading disability and psychosis, and were over represented in a subgroup of schizophrenic patients with greater cognitive compromise (Cannon et al, 1997;Crow et al, 1996;David et al, 1995;Satz and Green, 1999). Recent studies in schizophrenia support a decreased cerebral asymmetry rather than altered directional asymmetry as the potential candidate phenotype of abnormal lateralization that could contribute to individual susceptibility to schizophrenia (Sommer et al, 2001). In vivo imaging studies also pointed to the loss of asymmetry as a candidate marker to better characterize schizophrenia-associated deficits (Hietala et al, 1999(Hietala et al, , 1995Hsiao et al, 2003;Laakso et al, 2000).…”

“…A metaanalysis of 19 studies on schizophrenia showed that the prevalence of non-right-handedness was significantly higher in patients than in healthy subjects (Sommer et al, 2001). Similarly, in the meta-analysis of three prospective followup studies, pre-schizophrenic subjects were significantly more often non-right-handed than the general population (Sommer et al, 2001).…”

“…A metaanalysis of 19 studies on schizophrenia showed that the prevalence of non-right-handedness was significantly higher in patients than in healthy subjects (Sommer et al, 2001). Similarly, in the meta-analysis of three prospective followup studies, pre-schizophrenic subjects were significantly more often non-right-handed than the general population (Sommer et al, 2001). Furthermore, in vivo imaging studies of schizophrenia have provided evidence that the right-left asymmetry of the dopamine (DA) synthesis capacity and of the dopamine transporter (DAT) binding in the caudate are both lost in antipsychotic-naive patients (Hietala et al, 1999(Hietala et al, , 1995Hsiao et al, 2003;Laakso et al, 2000).…”

“…Based on the DA hypothesis of schizophrenia, which attributes the positive schizophrenic symptoms to a hyperdopaminergic state (Carlsson and Lindqvist, 1963;Snyder, 1976), and the decreased lateralization in schizophrenic patients (Sommer et al, 2001), we hypothesized that hyperactivity of the dopaminergic system could be associated with a reduced functional brain asymmetry.…”

Asymmetry within and around the human planum temporale is sexually dimorphic and influenced by genes involved in steroid hormone receptor activity

“…The PT has been characterized as a computational hub for processing spectrotemporal variation in auditory perception (Griffiths & Warren, 2002), as well as having a role in mapping acoustic speech signals to frontal lobe articulatory networks (Hickok & Poeppel, 2007), and in auditory attention (Hirnstein, Westerhausen, & Hugdahl, 2013). Given these important roles of the PT in speech and language, and its asymmetrical nature in the typically developed brain, there has been much interest in whether individual differences in PT asymmetry are associated with traits that involve changes in language cognition, including dyslexia, reduced verbal ability, and schizophrenia (Eckert et al, 2008;Frank & Pavlakis, 2001;Hasan et al, 2011;Kawasaki et al, 2008;McCarley et al, 2002;Oertel et al, 2010;Shapleske et al, 1999;Sommer, Ramsey, Kahn, Aleman, & Bouma, 2001). These studies have shown that alterations in PT asymmetry may be relevant to some etiological subtypes of these complex traits, although are not necessarily a universal feature of them (Bishop, 2013).…”