Title: Brain connectivity of the serotonergic system

PhD-student: Vincent Beliveau, NRU

Abstract:

The serotonin (5-HT) system plays a central role in the regulation of brain functions. It has been involved in a broad range of functions and implicated in the pathophysiology of neuropsychiatric illnesses. However, serotonergic brain functions are difficult to study using conventional imaging techniques and advanced methods are required.

In this project we first propose to identify intrinsic brain activity related to dorsal and median raphe nuclei, the seat of serotonergic projections throughout the brain. This was previously impossible as the raphe nuclei are not visible on normal MRI, however they can be accurately delineate from the 5-HT transporter images. Initial results indicate the existence of a resting-state network related to these nuclei. We then propose to construct an atlas of the 5-HT receptors and transporter (5-HT1A, 5-HT1B, 5-HT2A, 5-HT4 and 5-HTT) from data available in the Center for Integrated Molecular Brain Imaging (CIMBI) database and to perform the multivariate analyses of this atlas. The CIMBI database is unique in its genre and size and regroups high-resolution PET data for multiple tracers targeting the 5-HT system, structural and functional MRI data and a large battery of psychological tests. Finally, we will combine the results from the resting-state analysis and the multivariate analysis of the atlas to guide the investigation of the effect of GnRHa, a pharmacological challenge thought the influence the 5-HT system. The GnRHa dataset is part of the CIMBI database and contains high-resolution [11C]DASB images of the 5-HTT system, functional and structural MRI data.