The classic mutant dunce1 is amnesic for olfactory conditioning and hypermnesic for context recognition.

MARIO RAFAEL PAGANI; D'ODORICO CAROLINA; ASSOF IVAN

Cordoba

Congreso; XXXIV Congreso anual de la sociedad Argentina de investigación en neurociencias; 2019

Sociedad Argentina de Investigaciones en Neurociencias

Habituation is the most basic form of learning. It describes the decrease of a behavioral response to a repeated non-threatening sensory stimulus. The mechanisms of habituation are considered to be a prerequisite for other forms of learning. Suggestively, genes involved in intellectual disability are required for reflexive habituation. However, very little is known about habituation in motivated behaviors. Here we established a learning paradigm of context recognition in Drosophila, in which habituation and sensitization were predominant behaviors during learning and memory, respectively. We characterized the behavioral response of flies subjected to distinct protocols composed by one or two training trials with different length and different inter-trial intervals. Protocols with longer training trials led to an increased memory. The dunce (dnc) PDE restricts the level of cAMP at the presynapse, a function that is widely accepted to cause deficits in short-lived memory performances once deregulated in dnc1 (PDE loss-of-function) mutants. Surprisingly, dnc1 animals showed an increased short-term memory to the context, contrary to what had been shown in olfactory conditioning. Consistently, during training dnc1 showed a stronger habituation than wild-type flies, suggesting a better learning. These results show that the real nature of some classic mutants is more complex than we previously thought, and it might depend on the specific brain function involved.