Planum temporale asymmetry reversal in schizophrenia: replication and relationship to gray matter abnormalities

Abstract

I nvestigators studying the brains of schizophrenic patients have paid particular attention to limbic (mesial) temporal regions, following clinical observations of symptomatic schizophrenias (1). Neuropathologic examinations (2) and, later, magnetic resonance imaging (MRI) studies (3-5) showed temporal limbic abnormalities, including smaller than normal amygdala, hippocampus, entorhinal cortex, and parahippocampal gyrus.More recently, investigators have also studied the lateral temporal neocortex, which to a large extent is anatomically and functionally separate from mesial temporal structures. One neocortical region, the superior temporal gyrus, has been most often assessed, initially on the basis of physiologic observations (6). We (3) first noted low volume of the anterior superior temporal gyrus, associated with the severity of auditory hallucinations. Shenton et al. (4) reported low volume of the posterior superior temporal gyrus gray matter, associated with severity of thought disorder. Certain of these findings were later replicated (e.g., references 7 and 8), although not universally (9), and supported by related functional studies (10-12).The planum temporale is a portion of the surface of the posterior superior temporal gyrus. It has interested schizophrenia researchers for several reasons. These include evidence of abnormalities of language (13), electrophysiology, and brain asymmetries (14-16) associated with schizophrenia. To our knowledge, there has been only one neuropathologic study of the planum temporale that compared schizophrenic patients and a normal comparison group (17). This assessed both surface areas and volumes, indicating reversed asymmetry

Local Gyrification Index in Probands with Psychotic Disorders and Their First-Degree Relatives

“…This cingulate dysfunction has been postulated to disrupt the modulation of prefronto-temporal integration in schizophrenia (84). The observed temporal regions ofhypogyria also are consistent with prior observations of similarly localized surface area, symmetry, and folding abnormalities in schizophrenia (96-99). …”

Morphometry of superior temporal gyrus and planum temporale in schizophrenia and psychotic bipolar disorder

“…Abnormalities in the posterior or caudal STG which includes the planum temporale (PT) have been associated with auditory hallucinations. Specifically, reduced laterality of the STG and PT (Barta et al, 1997; McCarley et al, 2002) has been replicated by several recent studies (Hasan et al, 2011; Oertel et al, 2010; Takahashi et al, 2009). However, the diagnosis of schizophrenia is often confused with that of psychotic bipolar disorder because of the presence of psychotic symptoms in the latter (Brown et al, 2011; Hulshoff Pol et al, 2012; Yu et al, 2010).…”

Symptom trajectories and psychosis onset in a clinical high-risk cohort: The relevance of subthreshold thought disorder

“…The specific neural correlates of disorganized communication have not yet been identified among at-risk participants, though as a forme fruste of thought disorder, it would be expected to be related to pathology in the left superior temporal gyrus, including reduction in its gray matter volume (Barta et al, 1997; Menon et al, 1995; Sans-Sansa et al, 2013; Shenton et al, 1992; Weinstein et al, 2007) and in its functional activity (Kircher et al., 2001; Sans-Sansa et al, 2013; Weinstein et al, 2007). The left superior temporal gyrus is a biologically plausible neural substrate for disorganized communication as it is critical for language comprehension and production.…”