Opposite actions of dopamine on aversive and appetitive memories in a crab

MARTÍN KLAPPENBACH; HÉCTOR MALDONADO; LAURA KACZER; FERNANDO LOCATELLI

Huerta Grande, Córdoba

Congreso; XXVI Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia; 2011

Sociedad Argentina de Neurociencias (SAN)

The understanding of how the reinforcement is represented in the central nervous system during memory formation is a current issue in neurobiology. In insects, it is widely accepted that dopamine (DA) mediates aversive reinforcements. However, the idea of DA being exclusively involved in aversive memory is challenged in the present study. Here we address the involvement of DA in aversive and appetitive memories in the crab Chasmagnathus. We found that DA-receptor antagonists impair aversive memory consolidation, in agreement with previous reports in insects, while administration of DA facilitates memory formation after a weak training protocol. By contrast, DA treatment was found to impair appetitive memory formation, revealing a yet not described action of this amine. In addition, as a first step to elucidate the neuroanatomical correlates of DA action on memory, we mapped dopaminergic neurons in the central nervous system of the crab. Results of the current study together with those obtained in a previous work about the role of octopamine (OA) suggest that each amine (DA and OA) has a dual action on memory processes. On the one hand, they mediate the reinforcement signal throughout training and, on the other, they interfere with the formation of memory of the opposite sign.