PET imaging of cortical S₂ serotonin receptors after stroke: lateralized changes and relationship to depression

Patients with right-hemisphere strokes (N = 9) more than 1 year after injury had greater cortical binding of (3-N-[¹¹C]methyl)spiperone than a similar group of patients with left-hemisphere strokes (N = 8) or normal control subjects (N = 17). The higher S₂ serotonin receptor binding occurred in uninjured regions of the right parietal and temporal cortex. The ratio of binding in the ipsilateral to contralateral cortex showed a significant negative correlation with severity of depression scores in the left temporal cortex. These findings suggest that the biochemical response of the brain may be different depending on which hemisphere is injured and that some depressions may be a consequence of the failure to upregulate serotonin receptors after stroke.