Venue: Centre Broca Nouvelle-Aquitaine
Thesis supervisor: Romuald NARGEOT (INCIA)
Title : Contribution of a pacemaker neuronal activity to the expression and adaptation of a motivated behavior in Aplysia
Abstract
The expression of motivated behaviors, such as feeding or sexual acts, depends in part on the autonomous and variable functioning of the central nervous system, which selects and emits motor acts independently of sensory triggers. Sensory stimuli, such as rewards, help to adapt these central processes through learning. This thesis analyses the elementary neuronal mechanisms that are responsible for the spontaneous impulse for food-searching behavior and its adaptation by operant conditioning, a learning paradigm. The work was carried out in Aplysia, a simple animal model whose neural networks responsible for the spontaneous emission of the buccal motor pattern are identified. In isolated nervous preparations, it was shown that a spontaneous oscillation of the membrane potential in an identified decision-making neuron (B63) underlay the autonomous and variable emission of this motor pattern. This pacemaker oscillation depended on intracellular calcium dynamics and was differently modulated by serotonin and dopamine, two essential transmitters in the motivation and learning processes. Operant conditioning that regulated the motor pattern and increased the frequency of the motor pattern genesis did not modify this oscillation but changed the excitability and intrinsic membrane properties of the neuron. In conclusion, this work shows the contribution of a new calcium-dependent pacemaker property in a decision-making process that organizes the emission of a motivated behavior and its regulation by learning.
Key words: motivated behavior; decision-making; learning; neural network; pacemaker; neuromodulation; monoamines
Publications
Romuald Nargeot et Laura Puygrenier 2019. Operant Learning in Invertebrates Reference module in Life Sciences (chapitre de livre)
Cabanas M, Pistono C, Puygrenier L, Rakesh D, Jeantet Y, Garret M, Cho YH 2019. Neurophysiological and Behavioral Effects of Anti-Orexinergic Treatments in a Mouse Model of Huntington’s Disease Neurotherapeutics , volume 16 pages 1-13 (Article)
Jury
Président : Valérie FENELON
Rapporteur : Olivier PIERREFICHE
Rapporteur : Jean-Christophe SANDOZ
Examinateur : Catherine ARMENGAUD
Directeur de thèse : Romuald NARGEOT