title: Neurophysiological theory of kamin blocking in fear conditioning.
abstract: 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. The results suggest that opiate-mediated, negative-feedback control of US processing is too slow for efficient blocking of cue conditioning. The reason is that conditioning-produced synaptic modifications can be induced before the opiate-mediated inhibition has any substantial effect on US processing. The results suggest the existence of an additional, faster-acting, inhibitory neurotransmitter in the blocking circuit.
authors.affiliation: Department of Psychology, Yale University, New Haven, CT 06520, USA.
authors.forename: Diana B
authors.initials: DB
authors.lastname: Padlubnaya
authors.forename: Nirav H
authors.initials: NH
authors.lastname: Parekh
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Brown
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001921:Brain / Q000166:cytology; D003198:Computer Simulation; D003214:Conditioning, Classical / Q000502:physiology*; D005108:Extinction, Psychological; D005239:Fear; D005246:Feedback / Q000502:physiology; D016571:Neural Networks, Computer; D009474:Neurons / Q000502:physiology; D009482:Neurophysiology; D013569:Synapses / Q000502:physiology; D013997:Time Factors