The central objective of our team’s research is to understand how defined neuronal populations contribute to the selection, execution and adaptation of behaviors. Our work focuses on the dorsal striatum, a key node of the basal ganglia involved in motor control, action selection and instrumental learning, and on how its neuronal circuits dynamically encode behaviors in response to internal states and environmental contingencies.
A major line of our research is to uncover the general principles by which neural circuits represent actions and action repertoires, and how these encoding rules reconfigure across contexts and throughout learning. By combining longitudinal high-density in vivo calcium imaging in freely behaving mice with fine-grained behavioral reconstruction and machine-learning-based analyses, our team investigates how neural ensembles map behavioral action spaces and how these maps are updated when the animal’s internal state or environment changes. Within this framework, we view dopamine as a key signal that does not simply drive behavior, but reshapes the neural code itself: by modulating the gain, selectivity and stability of striatal ensemble activity, dopamine can bias which actions become represented as accessible, which competing actions are suppressed, and how these representations are refined throughout experience and instrumental learning.
More broadly, our research program integrates systems neuroscience, neurophysiology and computational approaches to establish general principles governing neural coding of behavior and learning. These questions are central to understanding basal ganglia-dependent disorders such as Parkinson’s disease, addiction, autism spectrum disorders and schizophrenia, in which action selection and behavioral flexibility are profoundly altered
Nucleus accumbens D1- and D2-expressing neurons control the balance between feeding and activity-mediated energy expenditure.
Walle, R., Petitbon, A., Fois, G.G., Varin, C., Montalban, E., Hardt, L., Contini, A., Angelo, M.F., Potier, M., Ortole, R., Oummadi, A., De Smedt-Peyrusse, V., Adan, R.R., Giros, B., Chaouloff, F., Ferreira, G., de Kerchove d’Exaerde, A., Ducrocq, F., Georges, F. and Trifilieff, P., 2024. Nature Communications, 15(1):2543.
DOI 10.1038/s41467-024-46874-9
Neuronal encoding of behaviors and instrumental learning in the dorsal striatum.
Varin, C. and de Kerchove d’Exaerde, A., 2024. Trends in Neurosciences, 48(1):77–91.
DOI 10.1016/j.tins.2024.11.003
Striatal projection neurons coexpressing dopamine D1 and D2 receptors modulate the motor function of D1- and D2-SPNs.
Bonnavion, P., Varin, C., Fakhfouri, G., Martinez Olondo, M.D.P., De Groote, A., Cornil, A., Lorenzo Lopez, J.R., Pozuelo Fernandez, E., Isingrini, E., Rainer, Q., Xu, K., Tzavara, E.T., Vigneault, E., Dumas, S., de Kerchove d’Exaerde, A.+ and Giros, B.+, 2024. Nature Neuroscience, 27(9):1783–1793.
DOI 10.1038/s41593-024-01694-4
*co-first authors, +co-corresponding authors.
The respective activation and silencing of striatal direct and indirect pathway neurons support behavior encoding.
Varin, C., Cornil, A., Houtteman, D., Bonnavion, P. and de Kerchove d’Exaerde, A., 2023. Nature Communications, 14(1):4982.
DOI 10.1038/s41467-023-40677-0
It takes two to tango: Dorsal direct and indirect pathways orchestration of motor learning and behavioral flexibility.
Bonnavion, P., Pozuelo Fernandez, E., Varin, C. and de Kerchove d’Exaerde, A., 2019. Neurochemistry International, 124:200–214.
DOI 10.1016/j.neuint.2019.01.009
Pharmacosynthetic Deconstruction of Sleep-Wake Circuits in the Brain.
Varin, C. and Bonnavion, P., 2019. Handbook of Experimental Pharmacology, 253:153–206.
DOI 10.1007/164_2018_183
Melanin-concentrating hormone-expressing neurons adjust slow-wave sleep dynamics to catalyze paradoxical (REM) sleep.
Varin, C., Luppi, P.-H. and Fort, P., 2018. Sleep, 41(6).
DOI 10.1093/sleep/zsy068
Sleep architecture and homeostasis in mice with partial ablation of melanin-concentrating hormone neurons.
Varin, C., Arthaud, S., Salvert, D., Gay, N., Libourel, P.-A., Luppi, P.-H., Léger, L. and Fort, P., 2016. Behavioural Brain Research, 298:100–110.
DOI 10.1016/j.bbr.2015.10.051
Glucose induces slow-wave sleep by exciting the sleep-promoting neurons in the ventrolateral preoptic nucleus: A new link between sleep and metabolism.
Varin, C., Rancillac, A., Geoffroy, H., Arthaud, S., Fort, P. and Gallopin, T., 2015. Journal of Neuroscience, 35(27):9900–9911.
DOI 10.1523/JNEUROSCI.0609-15.2015
Paradoxical (REM) sleep deprivation in mice using the small-platforms over-water method: polysomnographic analyses and melanin-concentrating hormone and hypocretin/orexin neuronal activation before, during and after deprivation.
Arthaud, S., Varin, C., Gay, N., Libourel, P.-A., Chauveau, F., Fort, P., Luppi, P.-H. and Peyron, C., 2015. Journal of Sleep Research, 24(3):309–319.
DOI 10.1111/jsr.12269
Lab Director: Serge Schiffmann
Lab Manager: Fabienne Reisen
Phone: +32 2 555 42 30
Laboratory of Neurophysiology, CP601 Bldg C, Room 3.134
ULB Campus Erasme,
808, Route de Lennik,
1070, Brussels, Belgium
Lab Director: Serge Schiffmann
Lab Manager: Fabienne Reisen
Phone: +32 2 555 42 30
Laboratory of Neurophysiology, CP601
Bldg C, Room 3.134
ULB Campus Erasme,
808, Route de Lennik,
1070, Brussels, Belgium
