Mathieu Wolff, Fabien Alcaraz et al. dans The J of N
Flexible use of predictive cues beyond the orbitofrontal cortex: role of the submedius thalamic nucleus. Fabien Alcaraz, Alain R. Marchand, Elisa Vidal, Alexandre Guillou, Angélique Faugère, Etienne Coutureau, Mathieu Wolff. Journal of Neuroscience. 23 septembre 2015.
Team: Neurobiology of executive functions/ Research team leader: Etienne Coutureau.
Lab: Cognitive and Integrative Neuroscience – Aquitaine Institute – Jean-René Cazalets
Flexible use of predictive cues beyond the orbitofrontal cortex: role of the submedius thalamic nucleus. Fabien Alcaraz, Alain R. Marchand, Elisa Vidal, Alexandre Guillou, Angélique Faugère, Etienne Coutureau, Mathieu Wolff. Journal of Neuroscience. 23 septembre 2015.
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In a continuously changing world, living organisms must select appropriate options to fulfill their needs. Adaptive responding when unexpected events occur in the environment is critical for survival. In this study, we identify a thalamocortical circuit supporting such adaptive responding, based on a thalamic nucleus of previously unknown functions.
High order cognitive functions associated with adaptive behaviors are built upon elementary processes highly conserved between species. They are thought to be critically supported by the prefrontal cortex, classically considered as the most evolved brain region.
To investigate whether neuronal circuits supporting these processes may extend beyond the prefrontal corex we first employed a tract-tracing approach to identify the principal sources of afferent of this cortical region. Dextran injections in the orbitofrontal cortex revealed unusually high labelling at the thalamic level, corresponding to the submedius thalamus, a brain region whose functions were not known.
Second, we performed neurotoxic lesions of either the orbitofrontal or the submedius nucleus of the thalamus in separate cohorts of rats. These rats were then submitted to a task assessing the ability to make flexible use of Pavlovian associations (Figure 1B). None of the lesion prevented the rats from learning that auditory cues signaled the delivery of the reward. However, when the contingency between the conditional stimulus and the food reward was degraded by providing “free” rewards (i.e. not signaled by the auditory cue) only sham rats exhibited adaptive responding by reducing their visits to the magazine during this specific stimulus.(Figure C)
Collectively, these data point to the submedius nucleus as a critical component of a thalamocortical circuit supporting the updating of the contingency between relevant environmental items. Moreover, this suggests that numerous neuronal circuits supporting adaptive behaviors may rely on a specific functional contribution of the thalamus, in agreement with recent evidence in the literature (Alcaraz et al., Brain Structure and Function 2014 ; Wolff et al., Neuroscience and Biobehavioral Reviews 2015).
Understanding the functional connectivity these specific thalamocortical circuits represents a major issue for the coming years with considerable relevance for many pathological conditions such as schizophrenia or addiction.
Flexible use of predictive cues beyond the orbitofrontal cortex: role of the submedius thalamic nucleus. Fabien Alcaraz, Alain R. Marchand, Elisa Vidal, Alexandre Guillou, Angélique Faugère, Etienne Coutureau, Mathieu Wolff. Journal of Neuroscience. 23 septembre 2015.
See the press release from the CNRS : http://www2.cnrs.fr/presse/communiq…
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Blogs:
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http://dyslectern.info/2015/09/27/t…
Translation available at several places:
http://www2.cnrs.fr/en/2627.htm
http://medicalxpress.com/news/2015-…
http://www.sciencedaily.com/release…
http://www.healthcanal.com/brain-ne…
http://neurosciencenews.com/decisio…
Spanish version: http://axxon.com.ar/noticias/2015/0…
Turkish version: http://www.tipacilar.com/karar-verm…
Dernière mise à jour le 06.10.2015
1er auteur
Fabien Alcaraz
... soutiendra sa thèse le 17 décembre 2015 (co-supervision Etienne Coutureau / Mathieu Wolff), le détail des informations est à venir d’ici peu. Il pourra ensuite poursuivre ses travaux dans l’équipe DECAD pour finaliser un ultime projet grâce à l’obtention d’une bourse de soudure du Labex Brain.
Last update 04/04/18