Auditory P300 Abnormalities and Left Posterior Superior Temporal Gyrus Volume Reduction in Schizophrenia

Abstract

Abnormalities in the auditory P300 event-related potential are one of the most robust findings in schizophrenia. To investigate the brain source(s) of this major functional abnormality, we combined P300 recordings with the use of a new generation of magnetic resonance imaging (MRI) technology to examine specific temporal lobe gray matter regions of interest in schizophrenics and normal controls. In schizophrenics, gray matter volume reductions in the left posterior superior temporal gyrus (STG), which includes Heschl's gyrus and the planum temporale, were highly and specifically associated with both P300 amplitude reduction and left < right topographic asymmetry. In contrast, left hippocampus and parahippocampal gyrus gray matter volume reductions, although present in schizophrenics, were not associated with any P300 abnormalities. There were also no statistically significant correlations between P300 amplitude at any of the central or left-sided electrode sites or any of the MRI-defined volumes of gray matter regions of interest in the right temporal lobe, superior frontal gyrus, or cingulate gyrus; additional work will thus be required to determine the role of these regions, if any, in P300 generation, along with the role of other brain areas not examined in the present study. These initial data appear most compatible with a model that postulates a major role for bilateral STG sources in P300 generation: The strongly asymmetric STG volume reduction (left < < right STG volume) found in many schizophrenic subjects produces asymmetric P300 amplitudes (left < < right) at lateral electrode sites, where the influence of the abnormal region is most easily detected.

Semantic disturbance in schizophrenia and its relationship to the cognitive neuroscience of attention

“…Paralleling these findings of structural brain abnormalities in left temporal areas thought to be intimately involved in lexical and semantic processing are ERP studies demonstrating auditory P300 reduction that are greater at left compared to right electrode sites in schizophrenia (McCarley et al, 1997). In addition, McCarley et al (1993) demonstrated that P300 amplitude at left temporal electrode site correlated significantly with reduced STG volume, as measured by quantitative MRI, in the same group of patients with schizophrenia. And perhaps most interesting in terms of a potential neurobiological substrate for schizophrenic thought disorder are findings linking reduced STG to an objective clinical measure of severity of thought disturbance, as assessed by the TDI (Shenton et al, 1992).…”

Increased hippocampal volume in schizophrenics' parents with ancestral history of schizophrenia

“…In the neuropsychological evaluation of these saine parents, we found that they share the attentional dysfunction that also characterizes the probands, but not the deficits in learning (Harris et al, 1996). Some, but not all, studies have shown that reduced voluines of temporoliinbic structures have a relationship to diininished performance on specific neuropsychological measures in schizophrenia (Golden et al, 1980;Hoff et al, 1992;Nestor et al, 1993). A population of schizophrenic individuals is likely the outcoine of multiple selections for both genetic and environinental factors that result in brain dysfunction.…”

“…volume of specific brain structures, notably the hippocampus (Bogerts et al, 1985;Cannon et al, 1989;Jeste and Lohr, 1989;Suddath et al, 1989) but other brain areas have been implicated as well (Turetsky et al, 1995;McCarley et al, 1993;Andreasen et al, 1989). However, the differences reported between schizophrenic patients and unrelated normal controls have typically been small, perhaps reflecting the wide range of brain structure volumes in the normal population (Nelson et al, 1998).…”

Brain activation during eye gaze discrimination in stable schizophrenia

“…Lesion and functional brain studies in humans and primates support the role of the fusiform gyrus in face processing (Allison et al 1994, Clark et al 1996, Kanwisher et al 1997. Gaze detection consistently involves areas of the superior temporal sulcus (Perrett et al 1992, Campbell et al 1999, Hoffman and Haxby 2000, Pelphrey et al 2004 and prefrontal lobe (Wicker et al 1998), that are already implicated in schizophrenia, based on volumetric and functional studies (McCarley et al 1993, Gur and Pearlson 1993, Zipursky et al 1994. Rosse et al (1994) reported that persons with schizophrenia, particularly those with paranoia, misidentified faces with averted gaze as making eye contact.…”