Objectif Functional-Magnetic Resonance Imaging (fMRI) has transformed our understanding of brain function due to its ability to noninvasively tag ‘active’ brain regions. Nevertheless, fMRI only detects neural activity indirectly, by relying on slow hemodynamic couplings whose relationships with underlying neural activity are not fully known. We have recently pioneered two unique MR approaches: Non-Uniform Oscillating-Gradient Spin-Echo (NOGSE) MRI and Relaxation Enhanced MR Spectroscopy (RE MRS). NOGSE-MRI is an exquisite microstructural probe, sensing cell sizes (l) with an unprecedented l^6 sensitivity (compared to l^2 in conventional approaches); RE MRS is a new spectral technique capable of recording metabolic signals with extraordinary fidelity at ultrahigh fields. This proposal aims to harness these novel concepts for mapping neural activity directly, without relying on hemodynamics. The specific objectives of this proposal are:(1) Mapping neural activity via sensing cell swellings upon activity: we hypothesize that NOGSE-fMRI can robustly sense subtle changes in cellular microstructure upon neural firings and hence convey neural activity directly. (2) Probing the nature of elicited activity via detection of neurotransmitter release: we posit that RE MRS is sufficiently sensitive to robustly detect changes in Glutamate and GABA signals upon activation. (3) Investigating widespread neural circuits in vivo via stroboscopic optogenetics: we propose to couple NOGSE-fMRI with optogenetics to resolve casual dynamics in global neural circuitry. Simulations for NOGSE-fMRI predict >4% signal changes upon subtle cell swellings; further, our in vivo RE MRS experiments have detected metabolites with SNR>50 in only 6 seconds. Hence, these two complementary –and importantly, hemodynamics-independent– approaches will represent a true paradigm shift: from indirect detection of neurovasculature couplings towards direct and noninvasive mapping of neural activity in vivo. Champ scientifique natural sciencesphysical sciencesopticsspectroscopy Mots‑clés Magnetic Resonance Imaging Functional Imaging fMRI neurotransmitters in vivo neuronal swelling MRI diffusion functional connectivity Programme(s) H2020-EU.1.3. - EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions Main Programme H2020-EU.1.3.2. - Nurturing excellence by means of cross-border and cross-sector mobility Thème(s) MSCA-IF-2014-EF - Marie Skłodowska-Curie Individual Fellowships (IF-EF) Appel à propositions H2020-MSCA-IF-2014 Voir d’autres projets de cet appel Régime de financement MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF) Coordinateur FUNDACAO D. ANNA DE SOMMER CHAMPALIMAUD E DR. CARLOS MONTEZ CHAMPALIMAUD Contribution nette de l'UE € 160 635,60 Adresse AVENIDA BRASILIA, CENTRO DE INVESTIGACAO DA FUNDACAO CHAMPALIMAUD 1400-038 Lisboa Portugal Voir sur la carte Région Continente Área Metropolitana de Lisboa Área Metropolitana de Lisboa Type d’activité Research Organisations Liens Contacter l’organisation Opens in new window Site web Opens in new window Participation aux programmes de R&I de l'UE Opens in new window Réseau de collaboration HORIZON Opens in new window Coût total € 160 635,60