Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

Appropriate reaction to changes in the environment is essential for survival. Appetitive stimuli decrease anxiety levels and activity of the stress-related hypothalamic-pituitary adrenal (HPA) axis in order to promote seeking and consumption of food. Conversely, imminent danger activates the HPA axis and suppresses feeding and other behaviors non-related to immediate fight or flight reaction. This coordination of specialized physiological systems requires precise functioning of interfaces between specific neuronal networks involved in stress and feeding behaviors.
In the stress-related neuronal network, the parvocellular part of the paraventricular hypothalamic nucleus (PVNp) is an important structure integrating stress-related signals and regulating activity of the HPA axis. In the food intake regulating network, the lateral hypothalamic area (LHA) plays the important role in initiation and maintenance of feeding. LHA neurons do not project directly to the PVNp, and how the activity of the LHA and PVNp neurons is coordinated during feeding and stress is unknown. The recent evidence suggests that the PVNp and LHA have reciprocal connections with the inhibitory gamma-aminobutyric acid (GABAergic) neurons of the anterior hypothalamic area (AHA). We detected local sub-populations of specialized neurons in the AHA that increase their activity in response to sucrose intake (sucrose-excited neurons) or are inhibited during sucrose intake and activated in response to stress (sucrose-inhibited/stress-activated). The general hypothesis of the present program is that the AHA neurons coordinate the activity of the PVNp and LHA neurons during feeding and stress. The program will test the following specific hypotheses :

1. Sucrose-excited GABAergic AHA neurons project to the PVNp; activation of these neurons during sucrose intake coincides with inhibition of the PVNp neurons.

2. Sucrose-inhibited/stress-activated GABAergic AHA neurons project to the LHA; inhibition of these neurons during sucrose intake coincides with activation of the LHA neurons.

3. Local inactivation of sucrose-excited neurons will activate the HPA axis and PVNp neurons. Conversely, local inactivation of sucrose-inhibited/stress-activated neurons will activate the LHA neurons and increase feeding.

The specific objectives of the program are to investigate the connections and functions of the AHA sucrose-excited and sucrose-inhibited neurons, and to study the functional role of the sucrose-excited and sucrose-inhibited AHA neurons in the coordination of feeding and stress networks.

This program will generate new knowledge on the mechanisms of coordinated activity of the specialized neuronal networks. This program will also create a great opportunity for training of highly qualified personnel in the avant-garde fields of electrophysiology and behavioral neuroscience.