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Titolo:
The role of nucleus accumbens dopamine in motivated behavior: a unifying interpretation with special reference to reward-seeking
Autore:
Ikemoto, S; Panksepp, J;
Indirizzi:
NIDA, Intramural Res Program, Behav Neurosci Branch, Baltimore, MD 21224 USA NIDA Baltimore MD USA 21224 ehav Neurosci Branch, Baltimore, MD 21224 USA Bowling Green State Univ, Dept Psychol, Bowling Green, OH 43402 USA Bowling Green State Univ Bowling Green OH USA 43402 g Green, OH 43402 USA
Titolo Testata:
BRAIN RESEARCH REVIEWS
fascicolo: 1, volume: 31, anno: 1999,
pagine: 6 - 41
SICI:
0165-0173(199912)31:1<6:TRONAD>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
VENTRAL TEGMENTAL AREA; INTRACRANIAL SELF-STIMULATION; INCREASED EXTRACELLULAR DOPAMINE; FREELY MOVING RATS; CONDITIONED AVOIDANCE-BEHAVIOR; INDUCED LOCOMOTOR-ACTIVITY; NON-PSYCHOSTIMULANT DRUGS; MEDIAL PREFRONTAL CORTEX; 3 STRIATAL SUBREGIONS; FREE FOOD-CONSUMPTION;
Keywords:
learning; operant; Pavlovian; arousal; aversion; novelty; self-stimulation; feeding; sexual behavior; conditioned reinforcement; locomotion; avoidance; latent inhibition; incentive motivation;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
311
Recensione:
Indirizzi per estratti:
Indirizzo: Ikemoto, S NIDA, Intramural Res Program, Behav Neurosci Branch, 550 NathanShock Dr, Baltimore, MD 21224 USA NIDA 550 Nathan Shock Dr Baltimore MD USA 21224 e, MD 21224 USA
Citazione:
S. Ikemoto e J. Panksepp, "The role of nucleus accumbens dopamine in motivated behavior: a unifying interpretation with special reference to reward-seeking", BRAIN RES R, 31(1), 1999, pp. 6-41

Abstract

Studies addressing behavioral functions of dopamine (DA) in the nucleus accumbens septi (NAS) are reviewed. A role of NAS DA in reward has long been suggested. However, some investigators have questioned the role of NAS DA in rewarding effects because of its role in aversive contexts. As findings supporting the role of NAS DA in mediating aversively motivated behaviors accumulate, it is necessary to accommodate such data for understanding the role of NAS DA in behavior. The aim of the present paper is to provide a unifying interpretation that can account for the functions of NAS DA in a variety of behavioral contexts: (1) its role in appetitive behavioral arousal, (2) its role as a facilitator as well as an inducer of reward processes, and(3) its presently undefined role in aversive contexts. The present analysis suggests that NAS DA plays an important role in sensorimotor integrationsthat facilitate flexible approach responses. Flexible approach responses an contrasted with fixed instrumental approach responses (habits), which mayinvolve the nigro-striatal DA system more than the meso-accumbens DA system. Functional properties of NAS DA transmission are considered in two stages: unconditioned behavioral invigoration effects and incentive learning effects. (1) When organisms are presented with salient stimuli (e.g., novel stimuli and incentive stimuli), NAS DA is released and invigorates flexible approach responses (invigoration effects). (2) When proximal exteroceptive receptors are stimulated by unconditioned stimuli, NAS DA is released and enables stimulus representations to acquire incentive properties within specific environmental context. It is important to make a distinction that NAS DA is a critical component for the conditional formation of incentive representations but not the retrieval of incentive stimuli or behavioral expressions based on over-learned incentive responses (i.e., habits). Nor is NAS DAessential for the cognitive perception of environmental stimuli. Therefore, even without normal NAS DA transmission, the habit response system still allows animals to perform instrumental responses given that the tasks take place in fixed environment. Such a role of NAS DA as an incentive-property constructor is not limited to appetitive contexts but also aversive contexts. This dual action of NAS DA in invigoration and incentive learning may explain the rewarding effects of NAS DA as well as other effects of NAS DA ina variety of contexts including avoidance and unconditioned/conditioned increases in open-field locomotor activity. Particularly, the present hypothesis offers the following interpretation for the finding that both conditioned and unconditioned aversive stimuli stimulate DA release in the NAS: NAS DA invigorates approach responses toward 'safety'. Moreover. NAS DA modulates incentive properties of the environment so that organisms emit approach responses toward 'safety' (i.e., avoidance responses) when animals later encounter similar environmental contexts. There may be no obligatory relationship between NAS DA release and positive subjective effects, even though these systems probably interact with other brain systems which can mediate such effects. The present conceptual framework may be valuable in understanding the dynamic interplay of NAS DA neurochemistry and behavior, both normaland pathophysiological. (C) 1999 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/01/20 alle ore 00:57:37