# 17 - Histological changes

# Histological changes

© SPMM Course 
6. Schizophrenia 
 
Gross changes 
 A decrease in brain weight, brain length and volume of the cerebral hemispheres enlargement of the 
lateral ventricles (especially temporal horns) 
 Reduced tissue volume in the thalamus, in temporolimbic structures including hippocampus, 
amygdala, parahippocampal gyrus. 
 White-matter reductions in parahippocampal gyrus or hippocampus 
 An increased incidence of a cavum septi pellucidi is noted. 
 Basal ganglia volume reduction was noted especially in preneuroleptic era, in the catatonic subgroup. 
Enlargement of basal ganglia is now more common in schizophrenia as a consequence of treatment 
with classical neuroleptics, which can be reversed by the use of atypical substances. 
 Schizophrenia-like psychosis is commoner in temporal lobe epilepsy when the focus is in the left 
hemisphere. 
 The planum temporale, the posterior superior surface of the superior temporal gyrus, is a highly 
lateralized brain structure involved with language. In schizophrenic patients, a consistent reversal of 
the normal left-larger-than- right asymmetry of planum temporale surface area is noted. Heschl's 
gyrus (primary auditory cortex) showed no differences between the left and right sides. 
 
Histological changes 
 No evidence for astrogliosis in schizophrenia 
 Reduced cell numbers or cell size has been described especially affecting neurons in the hippocampus 
and DLPFC. 
 Increase in neuronal density, which may relate to the observed decrease in neuronal size (with 
decreased dendritic arborization and a decreased neuropil compartment) has been reported. 
 Subtle cytoarchitectural anomalies were described in the hippocampal formation, frontal cortex, e.g. a 
significant cellular disarray in the CA3–CA4 interface 
 Synaptic studies in the hippocampus and DLPFC in schizophrenia show decrements in presynaptic 
markers. These changes may reflect a reduction in the number of synaptic contacts formed and 
received in these areas and supports the hypothesis of excessive synaptic pruning in schizophrenia. 
 Glutamatergic synapses may be especially vulnerable in the hippocampus and perhaps the DLPFC, 
with predominantly GABAergic involvement in the cingulate gyrus. 
 Antipsychotics alter synaptic and neuronal morphology, particularly in the caudate–putamen and 
may increase glial density in the prefrontal cortex.