A Little Look Inside the Brain
One of the key strategies in the search for some biological basis for schizophrenia is to locate abnormalities in the structure of the brain. Comparing the size, volume, cell count and function of the brain can be undertaken during autopsy but, most significantly perhaps, the use of scanning techniques such as magnetic resonance imaging (MRI) allows investigation of the living brain. What have these investigations revealed? In this sharepost I highlight just a few of the approaches used in the study of the brain and the findings they reveal.
Early approaches looked for distinct differences in the anatomy of the brain between people with schizophrenia and those without. These differences are still being sought but in ever more sophisticated ways. In terms of the size and weight of the brain, research findings are mixed. Some indicate a decrease of brain weight by up to 10 per cent yet others find no difference in the size and weight of the brain in people with schizophrenia.
Because the limbic system of the brain is considered the center of emotions, cell loss has been investigated in this area. Studies tend to show cell loss does occur as does unusual cell connectivity with another area of the brain called the hypothalamus.
Mid brain structures and the large bundle of fibers that connect the brain hemispheres have also been studied. Some changes to the mid brain have been reported but these may be due to long term effects of neuroleptic treatments.
The most active area of research, certainly over the past 20 years or so, has been in relation to brain imaging. A variety of techniques can look at highly localized areas of the brain, as well as the activity of neurone receptors. In terms of the structure of the brain, the fluid filled cavities known as ventricles have been shown to be enlarged in many cases. However, repeat scans of people with enlarged ventricles show no worsening over time, which dismisses the idea of any process of degeneration.
So far, everything I've said tends to point to little in the way of significant differences between people with schizophrenia and the controls they are compared with. This isn't always the case as many studies have revealed that the activity of the brain of people with schizophrenia tends to be underactive in the tempero-frontal region. This has become known as "hypofrontality", a situation far more common in chronic patients. Other findings have revealed higher levels of blood flow in areas of the brain associated with auditory hallucinations.
Ever more ingenious studies continue to reveal how the brain coordinates activities during everyday tasks and more complex cognitive routines. The more we discover about the brain in terms of its development, its function and the difference between abnormal and normal functioning, the closer we come to more effective treatments for diseases affecting the brain.
Birchwood, M., Jackson, C (2005) Schizophrenia. Psychology Press.