Several planimetric postmortem studies of the whole cortex have been performed, some reporting significant reduction of cortical volume (12 per cent) and central grey matter (6 per cent) and others reporting no difference in volumes of cortex, white matter and whole hemispheres between schizophrenics and controls. Other general brain parameters measured have shown reduced brain length, brain weight, and increased ventricular area/volume.
Since the first report of reduced tissue volume in temporolimbic structures of schizophrenics, (3°) numerous quantitative or qualitative anatomical postmortem studies on limbic structures of schizophrenics were published. Of these studies the majority found subtle structural changes (15-20 per cent mean volume reduction) in at least one of the investigated areas, whereas only a few yielded entirely negative results. The findings comprise reduced volumes or cross-sectional areas of the hippocampus, amygdala, parahippocampal gyrus, which were later corroborated by morphometric magnetic resonance imaging (MRI) studies.Figure 1 demonstrates the subtle bilateral volume reduction of the hippocampus in schizophrenics and furthermore visualizes the kind of hypoplastic appearance of the anterior hippocampus, which can be seen in about a third of the patients (lower row of the photographs). Other findings in limbic brain regions are left temporal horn enlargement, white-matter reductions in parahippocampal gyrus or hippocampus, and an increased incidence of a cavum septi pellucidi.
Fig. 1 Hippocampal volumes (left) and representative photographs at the level of the mamillary body (right) in schizophrenics and controls.
Unchanged volumes of the striatum and external pallidum but a subtle volume decrease in the internal pallidal segment were found in brains from the preneuroleptic era. Pallidal volume reduction was due to a reduction in the catatonic subgroup. These initial findings have to be pursued, as longitudinal MRI studies suggest that enlargement of basal ganglia can be seen in schizophrenia as a consequence of treatment with classical neuroleptics, which can be reversed by the use of atypical substances.
After initially finding no volumetric changes in the thalamic nuclei, subsequently the area/volume of the mediodorsal nucleus and anteroventral thalamic nucleus were found to be decreased.
Changes in area measurements of the corpus callosum were described in some studies. The findings, however, are inconsistent; there are reports of increased as well as of decreased midline areas. More consistent are reports of shape abnormalities, in that the sex difference in anterior and posterior callosal thickness in normal controls seems to be reversed in schizophrenics and the mean curvature in the corpus callosum is bent upwards.
Findings of decreased volume of the substantia nigra and the periventricular grey matter as well as no volumteric change in the locus coeruleus await replication.
In summary, macroscopic morphometric postmortem studies demonstrate increased ventricular size and volume/area reduction of temporolimbic areas in schizophrenia. Findings on other regions such as the basal ganglia, thalamus, cerebellum, and brainstem await replication.
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Autism is a developmental disorder that manifests itself in early childhood and affects the functioning of the brain, primarily in the areas of social interaction and communication. Children with autism look like other children but do not play or behave like other children. They must struggle daily to cope and connect with the world around them.