⇨  Teams  ⇨  Physiology of neural networks


Didier Desaintjan

My group is interested in understanding the synaptic and functional organization of the olfactory bulb, where olfactory sensory neurons that detect odorant molecules in the nasal cavities project their axons. Olfactory sensory neurons interact with mitral and tufted cells, the projection neurons of the bulb, within spherical strutures called glomeruli. The integration and transformation of the sensory input is modulated by diverse interneuron subtypes that, together, constitute 90% of all neurons in the bulb.

Our earlier work focused on intraglomerular excitatory interactions that generate the surprisingly complex and long-lasting synaptic activation of mitral and tufted cells (De Saint Jan and Westbrook, JNeurosci 2007; De Saint Jan et al., JNeurosci 2009; Najac et al., JNeurosci 2011).

Basal forebrain GABAergic axons (red) in the glomerular layer of the olfactory bulb. Calretinin-expressing PG cells (white) delineate three glomeruli.

Currently, our goal is to understand the functional implications of the diverse subtypes of periglomerular (PG) interneurons mediating intraglomerular inhibition as well as their modulation by long-range projections from the basal forebrain. Recently, we have described a major circuit and a PG cell subtype mediating intraglomerular inhibition (Najac et al., JNeurosci 2015). We have also characterized the properties of calretinin-expressing periglomerular cells (Benito et al., JNeurosci 2018) and revealed the connections made by basal forebrain GABAergic axons on diverse subtypes of periglomerular interneurons (Sanz Diez et al., JPhysiol 2019). Finally, our last study identifies a novel PG cell subtype with selective basal forebrain cholinergic inputs mediated by M1 muscarinic receptors (De Saint Jan, eLife 2022).

Selected publications

Target-specific control of olfactory bulb periglomerular cells by GABAergic and cholinergic basal forebrain inputs.
De Saint Jan D. eLife. 2022 Feb 28;11:e71965. Link

Basal forebrain GABAergic innervation of olfactory bulb periglomerular interneurons.
Sanz Diez A, Najac M, De Saint Jan D. J Physiol. 2019 May;597(9):2547-2563. Link

A Pool of Postnatally Generated Interneurons Persists in an Immature Stage in the Olfactory Bulb.
Benito N, Gaborieau E, Sanz Diez A, Kosar S, Foucault L, Raineteau O, De Saint Jan D. J Neurosci. 2018 Nov 14;38(46):9870-9882.