Chronic nicotine increases midbrain dopamine neuron activity and biases individual strategies towards reduced exploration in mice

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Dongelmans, Malou | Durand-de Cuttoli, Romain | Nguyen, Claire | Come, Maxime | Duranté, Etienne, K | Lemoine, Damien | Brito, Raphaël | Ahmed Yahia, Tarek | Mondoloni, Sarah | Didienne, Steve | Bousseyrol, Elise | Hannesse, Bernadette | Reynolds, Lauren, M | Torquet, Nicolas | Dalkara, Deniz | Marti, Fabio | Mourot, Alexandre | Naudé, Jérémie | Faure, Philippe

Edité par CCSD ; Nature Publishing Group -

International audience. Long-term exposure to nicotine alters brain circuits and induces profound changes in decision-making strategies, affecting behaviors both related and unrelated to drug seeking and consumption. Using an intracranial self-stimulation reward-based foraging task, we investigated in mice the impact of chronic nicotine on midbrain dopamine neuron activity and its consequence on the trade-off between exploitation and exploration. Model-based and archetypal analysis revealed substantial inter-individual variability in decision-making strategies, with mice passively exposed to nicotine shifting toward a more exploitative profile compared to non-exposed animals. We then mimicked the effect of chronic nicotine on the tonic activity of dopamine neurons using optogenetics, and found that photo-stimulated mice adopted a behavioral phenotype similar to that of mice exposed to chronic nicotine. Our results reveal a key role of tonic midbrain dopamine in the exploration/exploitation trade-off and highlight a potential mechanism by which nicotine affects the exploration/exploitation balance and decision-making.

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