Deficit schizophrenia patients show reduced FA in the left uncinate fasciculus
MedWire News: Patients with schizophrenia who have primarily negative symptoms (deficit schizophrenia) show reduced fractional anisotropy (FA) values in the left uncinate fasciculus, indicating disrupted communication between frontal and temporal areas of the brain, say Turkish researchers.
"A large number of neuroimaging and neurophysiology studies have shown anatomical and functional abnormalities in multiple brain regions of schizophrenia patients," observe Saffet Gonul (Ege University School of Medicine, Izmir) and team.
"Among them, frontal and temporal regions contain the most frequently reported abnormalities. These two regions function in concert to perform many functions, such as speech, social cognition, decision-making, and emotional learning; functions which are defective in many schizophrenia patients," they add.
The researchers explain that the uncinate fasciculus is the largest of three fasciculi that interconnect the frontal lobes to temporal regions.
To investigate whether patients with deficit schizophrenia differ from those with nondeficit schizophrenia regarding FA values in the uncinate fasciculus, the team studied 29 clinically stable schizophrenia outpatients treated with antipsychotic medication and 17 mentally healthy individuals (controls). There were no significant age or gender differences between the groups.
Of the patients with schizophrenia, 11 had deficit and 18 nondeficit schizophrenia, as assessed using the Schedule for Deficit Syndrome and the Positive and Negative Syndrome Scale (PANSS).
Overall, left uncinate fasciculus FA values were significantly lower in schizophrenia patients compared with controls, whereas there were no significant differences in right uncinate fasciculus FA values.
Among the patients, those with deficit schizophrenia showed significantly lower left uncinate fasciculus FA values than those with nondeficit schizophrenia, with no significant difference in right uncinate fasciculus FA values.
There were no correlations between uncinate fasciculus FA values and duration of illness, age of onset, PANSS scores, or antipsychotic doses, the researchers note.
Gonul and team conclude in Psychiatry and Clinical Neurosciences: "Our findings add weight to the view that the deficit syndrome reflects frontal and temporal impairment, and further suggest that communication between these regions is degraded by uncinate fasciculus pathology in the left hemisphere."
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By Mark Cowen