title: Hierarchy of neural organization in the embryonic spinal cord: Granger-causality graph analysis of in vivo calcium imaging data.
abstract: The recent development of genetically encoded calcium indicators enables monitoring in vivo the activity of neuronal populations. Most analysis of these calcium transients relies on linear regression analysis based on the sensory stimulus applied or the behavior observed. To estimate the basic properties of the functional neural circuitry, we propose a network approach to calcium imaging recorded at single cell resolution. Differently from previous analysis based on cross-correlation, we used Granger-causality estimates to infer information propagation between the activities of different neurons. The resulting functional network was then modeled as a directed graph and characterized in terms of connectivity and node centralities. We applied our approach to calcium transients recorded at low frequency (4 Hz) in ventral neurons of the zebrafish spinal cord at the embryonic stage when spontaneous coiling of the tail occurs. Our analysis on population calcium imaging data revealed a strong ipsilateral connectivity and a characteristic hierarchical organization of the network hubs that supported established propagation of activity from rostral to caudal spinal cord. Our method could be used for detecting functional defects in neuronal circuitry during development and pathological conditions.
authors.forename: Fabrizio De Vico
authors.initials: Fde V
authors.lastname: Fallani
authors.forename: Martina
authors.initials: M
authors.lastname: Corazzol
authors.forename: Jenna R
authors.initials: JR
authors.lastname: Sternberg
authors.forename: Claire
authors.initials: C
authors.lastname: Wyart
authors.forename: Mario
authors.initials: M
authors.lastname: Chavez
mesh_terms: D000465:Algorithms; D000818:Animals; D002118:Calcium / Q000737:chemistry*; D015984:Causality; D007814:Larva / Q000502:physiology; D009046:Motor Neurons / Q000502:physiology; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D016571:Neural Networks, Computer; D009434:Neural Pathways / Q000502:physiology; D059906:Neuroimaging / Q000379:methods*; D009474:Neurons; D013116:Spinal Cord / Q000033:anatomy & histology* / Q000196:embryology*; D015027:Zebrafish
chemical_list: D002118:Calcium