Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing

Latent inhibition (LI) is demonstrated when non-reinforced pre-exposure to a to-be-conditioned stimulus retards later learning. Learning is similarly retarded in overshadowing, in this case using the relative intensity of competing cues to manipulate associability. Electrolytic/excitotoxic lesions t...

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Main Authors: Nelson, Andrew J.D., Thur, Karen E., Marsden, C.A., Cassaday, Helen J.
Format: Article
Published: Sage 2012
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Online Access:https://eprints.nottingham.ac.uk/3210/
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author Nelson, Andrew J.D.
Thur, Karen E.
Marsden, C.A.
Cassaday, Helen J.
author_facet Nelson, Andrew J.D.
Thur, Karen E.
Marsden, C.A.
Cassaday, Helen J.
author_sort Nelson, Andrew J.D.
building Nottingham Research Data Repository
collection Online Access
description Latent inhibition (LI) is demonstrated when non-reinforced pre-exposure to a to-be-conditioned stimulus retards later learning. Learning is similarly retarded in overshadowing, in this case using the relative intensity of competing cues to manipulate associability. Electrolytic/excitotoxic lesions to shell accumbens (NAc) and systemic amphetamine both reliably abolish LI. Here a conditioned emotional response procedure was used to demonstrate LI and overshadowing and to examine the role of dopamine (DA) within NAc. Experiment 1 showed that LI but not overshadowing was abolished by systemic amphetamine (1.0 mg/kg i.p.). In Experiment 2, 6-hydroxydopamine (6-OHDA) was used to lesion DA terminals within NAc: both shell- and core- (plus shell-)lesioned rats showed normal LI and overshadowing. Experiment 3 compared the effects of amphetamine microinjected at shell and core coordinates prior to conditioning: LI, but not overshadowing, was abolished by 10.0 but not 5.0 µg/side amphetamine injected in core but not shell NAc. These results suggest that the abolition of LI produced by NAc shell lesions is not readily reproduced by regionally restricted DA depletion within NAc; core rather than shell NAc mediates amphetamine-induced abolition of LI; overshadowing is modulated by different neural substrates.
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spelling nottingham-32102020-05-04T16:32:15Z https://eprints.nottingham.ac.uk/3210/ Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing Nelson, Andrew J.D. Thur, Karen E. Marsden, C.A. Cassaday, Helen J. Latent inhibition (LI) is demonstrated when non-reinforced pre-exposure to a to-be-conditioned stimulus retards later learning. Learning is similarly retarded in overshadowing, in this case using the relative intensity of competing cues to manipulate associability. Electrolytic/excitotoxic lesions to shell accumbens (NAc) and systemic amphetamine both reliably abolish LI. Here a conditioned emotional response procedure was used to demonstrate LI and overshadowing and to examine the role of dopamine (DA) within NAc. Experiment 1 showed that LI but not overshadowing was abolished by systemic amphetamine (1.0 mg/kg i.p.). In Experiment 2, 6-hydroxydopamine (6-OHDA) was used to lesion DA terminals within NAc: both shell- and core- (plus shell-)lesioned rats showed normal LI and overshadowing. Experiment 3 compared the effects of amphetamine microinjected at shell and core coordinates prior to conditioning: LI, but not overshadowing, was abolished by 10.0 but not 5.0 µg/side amphetamine injected in core but not shell NAc. These results suggest that the abolition of LI produced by NAc shell lesions is not readily reproduced by regionally restricted DA depletion within NAc; core rather than shell NAc mediates amphetamine-induced abolition of LI; overshadowing is modulated by different neural substrates. Sage 2012-01-10 Article PeerReviewed Nelson, Andrew J.D., Thur, Karen E., Marsden, C.A. and Cassaday, Helen J. (2012) Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing. Journal of Psychopharmacology, 25 (12). pp. 1649-1660. ISSN 0269-8811 Dopamine; latent inhibition; nucleus accumbens; overshadowing http://jop.sagepub.com/content/25/12/1649 doi:10.1177/0269881110389211 doi:10.1177/0269881110389211
spellingShingle Dopamine; latent inhibition; nucleus accumbens; overshadowing
Nelson, Andrew J.D.
Thur, Karen E.
Marsden, C.A.
Cassaday, Helen J.
Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing
title Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing
title_full Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing
title_fullStr Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing
title_full_unstemmed Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing
title_short Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing
title_sort dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing
topic Dopamine; latent inhibition; nucleus accumbens; overshadowing
url https://eprints.nottingham.ac.uk/3210/
https://eprints.nottingham.ac.uk/3210/
https://eprints.nottingham.ac.uk/3210/