title: The functional divide for primary reinforcement of D-amphetamine lies between the medial and lateral ventral striatum: is the division of the accumbens core, shell, and olfactory tubercle valid?
abstract: When projection analyses placed the nucleus accumbens and olfactory tubercle in the striatal system, functional links between these sites began to emerge. The accumbens has been implicated in the rewarding effects of psychomotor stimulants, whereas recent work suggests that the medial accumbens shell and medial olfactory tubercle mediate the rewarding effects of cocaine. Interestingly, anatomical evidence suggests that medial portions of the shell and tubercle receive afferents from common zones in a number of regions. Here, we report results suggesting that the current division of the ventral striatum into the accumbens core and shell and the olfactory tubercle does not reflect the functional organization for amphetamine reward. Rats quickly learned to self-administer D-amphetamine into the medial shell or medial tubercle, whereas they failed to learn to do so into the accumbens core, ventral shell, or lateral tubercle. Our results suggest that primary reinforcement of amphetamine is mediated via the medial portion of the ventral striatum. Thus, the medial shell and medial tubercle are more functionally related than the medial and ventral shell or the medial and lateral tubercle. The current core-shell-tubercle scheme should be reconsidered in light of recent anatomical data and these functional findings.
authors.affiliation: Behavioral Neuroscience Branch, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland 21224, USA. sikemoto@intra.nida.nih.gov
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ikemoto
authors.forename: Mei
authors.initials: M
authors.lastname: Qin
authors.forename: Zhong-Hua
authors.initials: ZH
authors.lastname: Liu
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D003342:Corpus Striatum / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D003913:Dextroamphetamine / Q000008:administration & dosage*; D004192:Discrimination, Psychological / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D007839:Functional Laterality; D008297:Male; D009714:Nucleus Accumbens / Q000033:anatomy & histology / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012054:Reinforcement, Psychology; D012646:Self Administration
chemical_list: D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine