Researchers at the Boston Veterans Affairs Health Care System – Brockton Division, Harvard Medical School, and the University of Massachusetts-Boston are using new imaging technology to gather valuable information about the brains of people with schizophrenia.
Schizophrenia is a mental disorder that causes a separation between the thought processes and the emotions. Consumers may experience confusion of reality with hallucinations and/or delusions and may become paranoid. A change in personality with bizarre behavior may occur.
This new variety of magnetic resonance imaging (MRI) is called diffusion tensor imaging (DTI). Using DTI on patients with schizophrenia, neuropsychologists have related smaller sizes in two distinct webs of brain fibers to two distinct types of cognitive malfunction.
The findings appear in the October issue of Neuropsychology, which is published by the American Psychological Association (APA).
Diffusion tensor imaging (DTI) uses a regular MRI machine to analyze the movement of water molecules in and around the fibers that connect different parts of the brain. Neuroscientists use DTI to track indicators of brain "connectivity" – factors such as the number, thickness, density and arrangement of axons (the hair-like extensions of neurons, which send messages to other neurons) and thickness of the insulating/conducting fatty myelin sheath in which they are embedded. If weaker structural integrity reduces connectivity, lead author Paul Nestor, PhD, says it may mean that, "different brain areas do not communicate as well – with less synchrony or harmony, akin to an orchestra or band playing out of synch."
The researchers conducted neuropsychological tests on 41 patients with schizophrenia and 46 healthy controls, and used DTI scans on a 14-person subset of people with schizophrenia and healthy controls, a sample size typical of seminal studies of the human brain and comparable to early studies using functional MRI.
Brain images from the schizophrenic patients showed abnormalities in two functionally and anatomically different neural pathways – the uncinate fasciculus (UF) and the cingulate bundle (CB). Compared with age-matched controls, patients had smaller UF and CB. These bunches of axons are wrapped in myelin sheaths and bundled like electrical wire. The UF connects different parts of the frontal and temporal lobes and the CB connects parts of the prefrontal-cingulate regions. Each of these fiber tracts may help to define distinct neural networks. "We presume that the health of these fibers reflects the degree to which different parts of the brain are able to communicate," says Nestor.