Cocaine enhances the expression of fear-potentiated startle: evaluation of state-dependent extinction and the shock-sensitization of acoustic startle. 1995

M L Willick, and L Kokkinidis
Department of Psychology, University of Saskatchewan, Saskatoon, Canada.

Cocaine's effects on fear extinction and on the shock-sensitization of acoustic startle were examined. Following fear acquisition, rats exposed to the nonreinforced conditioned stimulus (CS) after cocaine administration demonstrated significant levels of fear-potentiated startle when evaluated in the drug-free state. The CS also increased startle amplitudes in subjects extinguished and tested with cocaine, indicating that mechanisms other than state-dependent learning are involved in the extinction deficit. The presentation of 10 footshocks augmented acoustic startle, and the shock enhancement was unaffected by cocaine preexposure. These data indicate that the aversive consequences of footshock relevant to the acquisition of conditional fear are not sensitized by the drug. It was suggested that cocaine reinforces fear responding to a threatening stimulus.

UI MeSH Term Description Entries
D008297 Male Males
D001921 Brain The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM. Encephalon
D003042 Cocaine An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake. Cocaine HCl,Cocaine Hydrochloride,HCl, Cocaine,Hydrochloride, Cocaine
D003214 Conditioning, Classical Learning that takes place when a conditioned stimulus is paired with an unconditioned stimulus. Reflex, Conditioned,Classical Conditioning,Classical Conditionings,Conditioned Reflex,Conditionings, Classical
D005108 Extinction, Psychological The procedure of presenting the conditioned stimulus without REINFORCEMENT to an organism previously conditioned. It refers also to the diminution of a conditioned response resulting from this procedure. Psychological Extinction,Extinction (Psychology),Extinctions (Psychology),Extinctions, Psychological,Psychological Extinctions
D005239 Fear The affective response to an actual current external danger which subsides with the elimination of the threatening condition. Threat Cues,Threat Sensitivity,Cue, Threat,Fears,Sensitivity, Threat,Threat Cue,Threat Sensitivities
D000161 Acoustic Stimulation Use of sound to elicit a response in the nervous system. Auditory Stimulation,Stimulation, Acoustic,Stimulation, Auditory
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001143 Arousal Cortical vigilance or readiness of tone, presumed to be in response to sensory stimulation via the reticular activating system. Vigilance, Cortical,Arousals,Cortical Vigilance
D001245 Association Learning The principle that items experienced together enter into a connection, so that one tends to reinstate the other. Association Learnings,Learning, Association,Learnings, Association

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