iCal
Raum:
Saal A6
Topic:
Besondere Veranstaltung
Topic 02: Psychische Störungen durch psychotrope Substanzen, Verhaltenssüchte, F1
English programme
Format:
Lecture
Dauer:
60 Minuten
Besonderheiten:
Q&A-Funktion
Sitzung wurde von A8 in en Raum A6 verschoben am 28.11.2019 von Frau Holzhausen gewünscht!
Accumbens shell and core dopamine in sucrose and drug reinforcement
Gaetano Di Chiara, Cagliari (Italy)
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Autor:in:
Gaetano Di Chiara, Cagliari (Italy)
Dopamine (DA) neurons terminate in areas of the forebrain involved in the evaluation and utilization of environmental stimuli to guide behavior finalized to the survival of the self and its species. This basic function is subserved by areas at the interface between sensory systems coding for those stimuli (rewards) such as taste, metabolic, sexual and maternal stimuli, and areas mediating the expression of behavior and the acquisition of response habits. Thus, as a result of learning, behavior , initially guided by response outcome, comes to be maintained by conditioned stimuli that precede response and make it relatively independent from outcome (habit). DA is involved at various steps in this process. DA can act itself as a reward , as indicated by experimental evidence of DA-dependent reinforcement elicited by indirect DA stimulants (amphetamine, cocaine) and by intracranial self stimulation (ICSS) with electrodes in rats (Olds and Milner, 1954) and with optogenetics in rats (Witten et al, 2011) and monkeys (Stauffer et al, 2016). Microdialysis and voltammetry studies show that DA is also released by conventional and drug rewards and reward-conditioned stimuli in subdivisions of the n.accumbens/ventral striatum. PET studies in humans have largely confirmed and extended these observations. Nonetheless, large discrepancies do exist on the relationship between behavior and changes in DA transmission in the two subdivisions of the ventral striatum, namely, the shell and the core. Microdialysis has the advantage , over voltammetry, to allow long term within subjects monitoring of DA transmission in rats responding for conventional and drug rewards. It will be shown that some basic commonalities as well differences between drug and sucrose reinforcement do exist as far as regards the changes in shell and core DA transmission. These similarities and differences might be relevant for the mechanism of conventional and drug reward & addiction.