Göran Sedvall seminar abstract

Mapping positive and negative symptoms using brain imaging

G. Sedvall1, R. Adolfsson2, I. Agartz1, S. Arnborg3, B. Ekholm1, H. Hall1, E. Jönsson1, T.F. McNeil4, G. Okugawa5, U. Ösby1, M.J. Owen6, L. Terenius1

1Karolinska Institutet, Department of Clinical Neuroscience, Karolinska Hospital, Stockholm, Sweden

The neurophysiological basis for positive and negative symptoms in patients with schizophrenic psychoses is still largely unknown.

The brain imaging techniques, MRI, fMRI and PET have introduced new possibilities to explore the localization of brain regions and systems involved in the manifestation of specific psychopathological phenomena.

PET and fMRI recording of regional blood flow changes in patients with schizophrenia have demonstrated increased flow in superior and medial temporal cortex during the experience of auditory hallucinations, reduced flow in superior and medial temporal cortex during the experience of auditory halluciantions. Reduced flow in prefrontal cortical regions has been reported in subjects with negative symtpoms.

Disorganized and paranoid symptoms appear to have more wide spread and diverse blood flow correlates. In general, few studies have been performed and most of them lack analyses of reliability and reproducibility. Molecular PET imaging of neuroreceptors and transporters using specific radioligands have so far demonstrated few correlations to psychopathological dimensions.

However, PET studies of drug-induced dopamine release have demonstrated positive relationships to aspects of positive of symptomalogy. More systematic studies in patients experiencing specific aspects of psychopathology should be performed with several imaging modalities in the same patient to explore specificity and reproducibility of changes observed.