Research interests
We work on the development, the evolution and the functional anatomy of the nervous system, using as a model system the autonomic or visceral nervous system (VNS). The VNS controls vital functions and bodily homeostasis by regulating respiratory, cardiovascular and digestive functions. Its core component is a series of reflex arcs travelling through the medulla, represented in the figure below.
Simplified schematic of the VNS circuits. AM: adrenal medulla; AP: area postrema; BM: branchiomotor neurons; C1: C1 adrenergic center; CB: carotid body; ENS: enteric nervous system; GG: geniculate ganglion; NG: nodose ganglion; nTS: nucleus of the solitary tract; PG: petrose ganglion; PSy: parasympathetic ganglia; pgSy: preganglionic sympathetic neurons (i.e. spinal visceromotor neurons); RTN: retrotrapezoid nucleus; Sy: sympathetic ganglia; VM: parasympathetic preganglionic (i.e. medullary visceromotor) neurons. This schematic includes BM neurons (which are usually omitted from descriptions of the VNS) owing to the fact that they are the respiratory motoneurons in aquatic vertebrates.
In the 90’s, we uncovered a highly unusual developmental property of these circuits, namely that the vast majority of their component neurons (depicted in red in the figure) depend on the same dedicated master gene: the homeodomain transcription factor Phox2b. The system-wide (or circuit specific) developmental role of Phox2b informs the current work of the lab on three main themes: the development of the VNS, its evolution on a large phylogenetic scale, and the functional anatomy —at the cellular level— of some of its poorly understood parts.
Last update : 17 September 2009