Placebo and Opioid Analgesia-- Imaging a Shared Neuronal Network
Predrag Petrovic,1
Eija Kalso,2
Karl Magnus Petersson,1
Martin Ingvar1*
It has been suggested that placebo analgesia involves both
higher order cognitive networks and endogenous opioid systems. The
rostral anterior cingulate cortex (rACC) and the brainstem are
implicated in opioid analgesia, suggesting a similar role for these
structures in placebo analgesia. Using positron emission tomography, we
confirmed that both opioid and placebo analgesia are associated with
increased activity in the rACC. We also observed a covariation between
the activity in the rACC and the brainstem during both opioid and
placebo analgesia, but not during the pain-only condition. These
findings indicate a related neural mechanism in placebo and opioid
analgesia.
1 Cognitive Neurophysiology Research Group,
Department of Clinical Neuroscience, Karolinska Institute, Stockholm
171 76, Sweden.
2 Pain Clinic, Department of
Anaesthesia and Intensive Care Medicine, Helsinki University Hospital,
Finland.
*
To whom correspondence should be addressed. E-mail:
martin{at}ingvar.com
