Two-photon imaging of capillary blood flow in olfactory bulb glomeruli.
Analysis of the spatiotemporal coupling between neuronal activity and cerebral blood flow requires the precise measurement of the dynamics of RBC flow in individual capillaries that irrigate activated neurons. Here, we use two-photon microscopy in vivo to image individual RBCs in glomerular capillaries in the rat dorsal olfactory bulb. We find that odor stimulation evokes capillary vascular responses that are odorant- and glomerulus-specific. These responses consist of increases as well as decreases in RBC flow, both resulting from independent changes in RBC velocity or linear density. Finally, measuring RBC flow with micrometer spatial resolution and millisecond temporal resolution, we demonstrate that, in olfactory bulb superficial layers, capillary vascular responses precisely outline regions of synaptic activation.
Laboratory of Neurophysiology, INSERM EPI 0002, Centre National de la Recherche Scientifique FRE2500, Ecole Supérieure de Physique et Chimie Industrielles de la Ville de Paris, 10 Rue Vauquelin, 75231 Paris, France.
Emmanuelle
E
Chaigneau
Martin
M
Oheim
Etienne
E
Audinat
Serge
S
Charpak
D000818:Animals; D001783:Blood Flow Velocity; D002196:Capillaries / Q000502:physiology*; D004912:Erythrocytes / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D009812:Odorants; D009830:Olfactory Bulb / Q000098:blood supply*; D017785:Photons; D051381:Rats; D017208:Rats, Wistar