Addiction expert Howard Fields published a very important paper this month in Nature Reviews Neuroscience. Given the paper's relative technical depth I asked Howard to summarize this research for the rest of us mortals. So he put together the following: (thanks Howard)

"Contrary to the intuitive sense that we passively receive signals from the outside world and that our experience reflects this input, evidence is growing that sensations are usually preceded by a decision process. To carry out this decision process the brain weighs different behaviors on a utility/cost scale and selects the optimal goal. Then it then screens all inputs for those that are task relevant and inhibits those that are not. This process is striking for the pain sensory pathway, which may be completely absent in the face of serious injuries, including bone fractures. The implementation of this phenomenon depends on the release of endogenous opioid peptides that activate a pain suppressing control system, under conditions in which it is not in the individual's interest to respond to such severe stimuli (A life threatening situation or one offering very large rewards)."

Here is the summary for the neuroscientists among you:

Opioid receptors are a family of related G-protein-coupled receptors. Both endogenous and exogenous ligands for these receptors have powerful motivational actions. Opioid actions on nociceptive transmission are exerted through a circuit that connects limbic forebrain and brainstem structures to spinal and trigeminal dorsal horn.

The opioid-mediated off-cell state is robustly activated by both aversive and appetitive motivational states. The reversal of placebo analgesia by naloxone indicates that it might be an example of an appetitive state.

The bottom line: Addiction science is advancing rapidly and brings with it profound changes for all aspects of society, including: neurocops, neurocompetitive advantage, and hopefully some less destructive leisure tools.