Loss of Asymmetry

Many structures are normally lateralized in the human brain with area or volume being consistently larger in one hemisphere or the other. Some asymmetries are related to lateralized functions such as language. Abnormal cerebral asymmetry in schizophrenia has been studied since its first observation in 1879 by Crichton-Browne. Many studies of schizophrenia have shown an absence or reversal of the normal cerebral asymmetries found in controls. These disruptions in normal asymmetry are thought to reflect abnormalities during development. The main regions where this asymmetry has been noted in neuropathological studies are the left superior temporal gyrus, a reversal of the normally larger left planum temporali, and loss of the normally larger left Sylvian fissure. Moreover, certain abnormalities in the brains of patients with schizophrenia are restricted to or worse in one hemisphere (usually the left) over the other. To site a few examples, schizophrenia subjects show thinning of the left parahippocampal gyrus, left temporal horn enlargement, reduction in size of the left medial temporal lobe, and loss of synaptic proteins from the left thalamus (Selemon, 2001).

0 0

Post a comment