Measuring dopamine neuromodulation in the thalamus: using [F-18]fallypride PET to study dopamine release during a spatial attention task.

We used the highly selective D2/D3 dopamine PET radioligand [F-18]fallypride to demonstrate that cognitive task induced dopamine release can be measured in the extrastriatal region of the thalamus, a region containing 10-fold fewer D2 dopamine receptors than the striatum. Human studies were acquired on 8 healthy volunteers using a single [F-18]fallypride injection PET imaging session. A spatial attention task, previously demonstrated to increase FDG uptake in the thalamus, was initiated following a period of radioligand uptake.