Neurophysiological theory of kamin blocking in fear conditioning.

Kamin blocking in fear conditioning is thought to reflect diminished processing of the unconditional stimulus (US) in the presence of a conditional stimulus (CS-super(+)) that was previously paired with this US. According to Fanselow's (1998) hypothesis, the CS-super(+) drives output from the amygdala that ultimately produces analgesia by causing opiate release onto afferent pain circuits. This hypothesis was explored quantitatively through neurophysiological simulations.