PhD: Fabien Alcaraz

Thalamocortical networks of decision making

Defended on December 7, 2015

Survival of living organisms depends on the ability to make decision adapted to their current needs and desires. Such an ability results from the integration of multiple basic cognitive processes such as events prediction and action control. These processes are best investigated within the framework of associative learning. Past research has demonstrated that these processes are supported by a widespread neuronal circuit, in which the prefrontal cortex and his major afferent structure, the mediodorsal thalamus (MD), play a central role. In this context, this thesis work aimed at investigating the functional role of the exchanges between these two structures in decision making.

In a first part of this work, we assessed the role of the MD in prediction and control. We showed that MD lesioned rats are unable to adapt their behavior to a change in reward value, in an experimental procedure asking the integration of instrumental and Pavlovian contingencies. This result confirmed the fundamental role of MD in goal representation. As a second step, we performed an anatomical study in order to characterize the architecture of the thalamocortical pathways arising from the MD.We first showed that multiple thalamocortical pathways originate from segregated neuronal populations within the MD. We also discovered a poorly known thalamic structure innervating the orbitofrontal cortex, the submedius nuclei. In order to understand the functional role of these pathways, we used a conditional chemogenetic technique aimed at inactivating neuronal populations selected on the basis of their projections. Using this technique, we showed that the animal’s abilities to represent either the value or the action-reward relationship depend on the directionality of MD and prefrontal cortex exchanges. Finally, we identified a specific role for the submedius nuclei in updating Pavlovian contingencies, by using a more classical lesioning approach.

Taken together, these results support the idea that decision making involved several thalamocortical loops, differentially supporting prediction and action control.

 

Publications
Alcaraz, F., Naneix, F., Desfosses, E., Marchand, A.R., Wolff, M. & Coutureau, E. Dissociable effects of anterior and mediodorsal thalamic lesions on spatial goal-directed behavior. Brain Struct. Funct. (2014). doi:10.1007/s00429-014-0893-7

Wolff, M., Alcaraz, F., Marchand, A. R. & Coutureau, E. Functional heterogeneity of the limbic thalamus: From hippocampal to cortical functions. Neurosci. Biobehav. Rev. 54, 120–130 (2015).

Alcaraz, F., Marchand, A.R., Vidal, E., Guillou, A., Faugere, A., Coutureau, E. & Wolff, M. Flexible Use of Predictive Cues beyond the Orbitofrontal Cortex: Role of the Submedius Thalamic Nucleus. J. Neurosci. 35, 13183–13193 (2015).

Alcaraz, F., Marchand, A. R, Courtant, G., Coutureau, E. & Wolff, M. Parallel inputs from the mediodorsal thalamus to the prefrontal cortex in the Rat. EJN (In revision).

Jury

  • Jean-Christophe CASSEL, rapporteur, Laboratoire de Neurosciences Cognitives et adaptatives, CNRS UMR 7364, Université de Strasbourg
  • Bruno POUCET, rapporteur, Laboratoire de Neurosciences Cognitives, CNRS UMR 7291, Université d’Aix-Marseille
  • Eric KREMER, examinateur, Institut de Génétique Moléculaire de Montpellier, CNRS UMR 5535, Université de Montpellier
  • Catherine LE MOINE, examinateur, Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, CNRS UMR 5287, Université de Bordeaux
  • Etienne COUTUREAU, directeur de thèse, Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, CNRS UMR 5287, Université de Bordeaux
  • Mathieu WOLFF, directeur de thèse, Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, CNRS UMR 5287, Université de Bordeaux

PhD supervisor

Etienne Coutureau, CNRS Researcher
Team Leader : Decision and Adaptation

Mathieu Wolff, CNRS Researcher

Team Decision and Adaptation

INCIA
Aquitaine Institute for Cognitive and Integrative Neuroscience (INCIA)

Last update: 6 April 2018