MRI anatomy of schizophrenia

Abstract

Structural magnetic resonance imaging (MRI) data have provided much evidence in support of our current view that schizophrenia is a brain disorder with altered brain structure, and consequently involving more than a simple disturbance in neurotransmission. This review surveys 118 peerreviewed studies with control group from 1987 to May 1998. Most studies (81%) do not find abnormalities of whole brain/intracranial contents, while lateral ventricle enlargement is reported in 77%, and third ventricle enlargement in 67%. The temporal lobe was the brain parenchymal region with the most consistently documented abnormalities. Volume decreases were found in 62% of 37 studies of whole temporal lobe, and in 81% of 16 studies of the superior temporal gyrus (and in 100% with gray matter separately evaluated). Fully 77% of the 30 studies of the medial temporal lobe reported volume reduction in one or more of its constituent structures (hippocampus, amygdala, parahippocampal gyrus).Despite evidence for frontal lobe functional abnormalities, structural MRI investigations less consistently found abnormalities, with 55% describing volume reduction. It may be that frontal lobe volume changes are small, and near the threshold for MRI detection. The parietal and occipital lobes were much less studied; about half of the studies showed positive findings. Most studies of cortical gray matter (86%) found volume reductions were not diffuse, but more pronounced in certain areas. About two thirds of the studies of subcortical structures of thalamus, corpus callosum and basal ganglia (which tend to increase volume with typical neuroleptics), show positive findings, as do almost all (91%) studies of cavum septi pellucidi (CSP). Most data were consistent with a developmental model, but growing evidence was compatible also with progressive, neurodegenerative features, suggesting a "two-hit" model of schizophrenia, for which a cellular hypothesis is discussed. The relationship of clinical symptoms to MRI findings is reviewed, as is the growing evidence suggesting structural abnormalities differ in affective (bipolar) psychosis and schizophrenia.

Schizophrenia Breakdown in the Well-regulated Lifelong Process of Brain Development and Maturation

“…Nevertheless, recent histopathologic and neuroimaging techniques have demonstrated subtle structural changes that provide clues to the disorder's pathophysiology and heterogeneity despite the failure to identify a single pathophysiologic "lesion" (Harrison 1999). Brain imaging studies of adult patients have consistently documented enlarged cerebral spinal fluid (CSF) volumes (sulcal and ventricular), as well as subtle decreases in total brain volume and smaller gray matter volumes in a variety of locations (cortical, medial temporal lobe structures, and thalamus) (for reviews see Lawrie and Abukmeil 1998;Nelson et al 1998;Pearlson and Marsh 1999;McCarley et al 1999;Wright et al 2000).…”

Planum Temporale and Heschl Gyrus Volume Reduction in Schizophrenia: A Magnetic Resonance Imaging Study of First-Episode Patients

“…[6][7][8][9][10][11][12][13][14] The impetus for much of this work is based on the role that the left (dominant) hemisphere PT plays in language processing [15][16][17] and the role that the HG plays in the initial processing of auditory information. [1][2][3] DeLisi et al 10 measured length of the sylvian fissure and reported asymmetry differences in patients with first-episode schizophrenia compared with controls. Reduced cortical PT volume was reported in a postmortem study in schizophrenia compared with controls, 18 and we reported reduced left PT gray matter volume and a reversal of PT asymmetry in patients diagnosed as having chronic schizophrenia.…”

A quantitative MR measure of the fornix in schizophrenia

“…Andreasen et al, 1994;Buchsbaum, 1996). Analyses of other areas of the brain, such as the frontal and parietal lobes, have yielded more equivocal results (again, see our reviews in Shenton et al, 1997Shenton et al, , 2000McCarley et al, 1999).…”

“…Of note, MR volumetric brain abnormalities have been consistently reported in medial temporal and temporal lobe structures (see reviews in Shenton et al, 1997Shenton et al, , 2000McCarley et al, 1999). Currently, the most robust MR findings include enlargement of the lateral ventricles, especially in the left temporal horn (e.g.…”

“…In fact, there are no reliable MR studies of the fornix in schizophrenia. This is particularly surprising given that the fornix is a key fiber tract connecting two structures, the hippocampus and thalamus, both of which have been implicated in schizophrenia (for the role of the hippocampus in schizophrenia, see review in Shenton et al, 1997;McCarley et al, 1999; for the role of the thalamus in schizophrenia, see Andreasen et al, 1990Andreasen et al, , 1994Corey-Bloom et al, 1995;Flaum et al, 1995;Buchsbaum, 1996;Andreasen, 1997;Shenton et al, 1997Shenton et al, , 2000Portas et al, 1998).…”