Appetitive overshadowing is disrupted by systemic amphetamine but not by electrolytic lesions to the nucleus accumbens shell.

Rachel Rutter Horsley, Paula M. Moran, Helen J. Cassaday

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

7 Dyfyniadau(SciVal)

Crynodeb

There is evidence that the indirect dopamine (DA) agonist amphetamine (AMP) can disrupt selective learning in an aversive overshadowing task, consistent with a role for the DA system in this form of salience manipulation. In the following experiments we assessed in the male Wistar rat: (1) whether amphetamine disruption of overshadowing extends to an appetitively motivated overshadowing task; and (2) whether selective electrolytic lesions to the n.acc (shell versus core subfields) disrupt appetitively motivated overshadowing. The experiments used sucrose reward pellets as the unconditioned stimulus (UCS). In each case, a conditioned stimulus (CS, light) was either conditioned alone or in compound together with a more intense CS (noise or tone). The presence of overshadowing was demonstrated as reduced conditioning to the light when it had been previously conditioned in compound compared to when it had been conditioned alone.

It was predicted that AMP and lesions to the n.acc shell would disrupt overshadowing. AMP was found to abolish overshadowing at 0.5 mg/kg, but not at 1 mg/kg. Contrary to prediction, the shell lesioned animals did not differ from shams. The results of Experiment 1 add to the evidence that the DA system can moderate salience processing of weaker predictors, also in cases where CS salience is manipulated directly via the physical intensities of the stimuli, as here. However, in terms of the brain structures involved, Experiment 2 suggests that, overshadowing is moderated by projections of the DA system without n.acc.
Iaith wreiddiolSaesneg
Tudalennau (o-i)172-181
Nifer y tudalennau9
CyfnodolynJournal of Psychopharmacology
Cyfrol22
Rhif cyhoeddi2
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - Maw 2008

Ôl bys

Gweld gwybodaeth am bynciau ymchwil 'Appetitive overshadowing is disrupted by systemic amphetamine but not by electrolytic lesions to the nucleus accumbens shell.'. Gyda’i gilydd, maen nhw’n ffurfio ôl bys unigryw.

Dyfynnu hyn