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.