Flexible Use of Predictive Cues beyond the Orbitofrontal Cortex: Role of the Submedius Thalamic Nucleus

F. Alcaraz, A. R. Marchand, E. Vidal, A. Guillou, A. Faugere, E. Coutureau, M. Wolff
Journal of Neuroscience. 2015-09-23; 35(38): 13183-13193
DOI: 10.1523/jneurosci.1237-15.2015

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1. J Neurosci. 2015 Sep 23;35(38):13183-93. doi: 10.1523/JNEUROSCI.1237-15.2015.

Flexible Use of Predictive Cues beyond the Orbitofrontal Cortex: Role of the
Submedius Thalamic Nucleus.

Alcaraz F(1), Marchand AR(1), Vidal E(1), Guillou A(1), Faugère A(1), Coutureau
E(1), Wolff M(2).

Author information:
(1)Centre National de la Recherche Scientifique and Université de Bordeaux,
Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, UMR 5287, 33076
Bordeaux, France.
(2)Centre National de la Recherche Scientifique and Université de Bordeaux,
Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, UMR 5287, 33076
Bordeaux, France .

The orbitofrontal cortex (OFC) is known to play a crucial role in learning the
consequences of specific events. However, the contribution of OFC thalamic inputs
to these processes is largely unknown. Using a tract-tracing approach, we first
demonstrated that the submedius nucleus (Sub) shares extensive reciprocal
connections with the OFC. We then compared the effects of excitotoxic lesions of
the Sub or the OFC on the ability of rats to use outcome identity to direct
responding. We found that neither OFC nor Sub lesions interfered with the basic
differential outcomes effect. However, more specific tests revealed that OFC
rats, but not Sub rats, were disproportionally relying on the outcome, rather
than on the discriminative stimulus, to guide behavior, which is consistent with
the view that the OFC integrates information about predictive cues. In subsequent
experiments using a Pavlovian contingency degradation procedure, we found that
both OFC and Sub lesions produced a severe deficit in the ability to update
Pavlovian associations. Altogether, the submedius therefore appears as a
functionally relevant thalamic component in a circuit dedicated to the
integration of predictive cues to guide behavior, previously conceived as
essentially dependent on orbitofrontal functions. Significance statement: In the
present study, we identify a largely unknown thalamic region, the submedius
nucleus, as a new functionally relevant component in a circuit supporting the
flexible use of predictive cues. Such abilities were previously conceived as
largely dependent on the orbitofrontal cortex. Interestingly, this echoes recent
findings in the field showing, in research involving an instrumental setup, an
additional involvement of another thalamic nuclei, the parafascicular nucleus,
when correct responding requires an element of flexibility (Bradfield et al.,
2013a). Therefore, the present contribution supports the emerging view that
limbic thalamic nuclei may contribute critically to adaptive responding when an
element of flexibility is required after the establishment of initial learning.

Copyright © 2015 the authors 0270-6474/15/3513183-11$15.00/0.

DOI: 10.1523/JNEUROSCI.1237-15.2015
PMID: 26400947 [Indexed for MEDLINE]


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