@article{d2943d1fc2cd4660bce519be60483852,
title = "Selective responding of nucleus accumbens core and shell dopamine to aversively conditioned contextual and discrete stimuli",
abstract = "Dopamine transmission within the nucleus accumbens has been implicated as a neurochemical substrate of associative learning processes. It has been suggested that the acquisition of classically conditioned fear to a specific environment, or context, differs fundamentally from the development of conditioned fear to a discrete stimulus, such as a light or a tone. In this study, we assessed extracellular dopamine in the rat nucleus accumbens shell and core during the expression of a conditioned fear response. Animals were aversively conditioned to either a context or a tone and extracellular dopamine was measured in the nucleus accumbens shell and core by in vivo microdialysis over the next 2 days as animals were returned first to the conditioning chamber (day 1: context test), and subsequently as animals were again returned to the chamber and presented with the conditioned tone stimulus (day 2: tone test). Dopamine levels in the core were significantly higher in the Context-Shock group compared to the Tone-Shock group during the 30-min exposure to context while dopamine levels in the nucleus accumbens shell did not differ significantly during the context test between groups. In contrast, extracellular dopamine in the shell but not the core of Tone-Shock animals increased significantly during presentation of the tone. Dopamine in both the shell and core remained unchanged during the tone test in the Context-Shock groups. These data suggest distinct roles for shell and core dopamine transmission in the expression of a conditioned emotional response. While dopamine increased in the shell primarily during the presentation of a discrete tone conditioned stimulus, core dopamine responded more to a contextual conditioned stimulus. These results may reflect differences in either the type of information acquired or the salience of the learned associations which are formed to a context vs. a discrete tone cue.",
keywords = "Conditioned fear, Context, Freezing, Microdialysis",
author = "Pezze, {M. A.} and Heidbreder, {C. A.} and J. Feldon and Murphy, {C. A.}",
note = "Funding Information: This research was supported by grants from the Swiss National Science Foundation (Grants 3100-051657 and 3100-042009.94) and the Swiss Federal Institute of Technology. The authors thank the animal facility team for their care and maintenance of the animals used in this study and Mr. Peter Schmid for his excellent technical assistance.",
year = "2001",
month = dec,
day = "5",
doi = "10.1016/S0306-4522(01)00403-1",
language = "אנגלית",
volume = "108",
pages = "91--102",
journal = "Neuroscience",
issn = "0306-4522",
publisher = "Elsevier Ltd.",
number = "1",
}