The spatiotemporal organization of cerebellar network activity resolved by two-photon imaging of multiple single neurons.
In order to investigate the spatiotemporal organization of neuronal activity in local microcircuits, techniques allowing the simultaneous recording from multiple single neurons are required. To this end, we implemented an advanced spatial-light modulator two-photon microscope (SLM-2PM). A critical issue for cerebellar theory is the organization of granular layer activity in the cerebellum, which has been predicted by single-cell recordings and computational models. With SLM-2PM, calcium signals could be recorded from different network elements in acute cerebellar slices including granule cells (GrCs), Purkinje cells (PCs) and molecular layer interneurons. By combining WCRs with SLM-2PM, the spike/calcium relationship in GrCs and PCs could be extrapolated toward the detection of single spikes. The SLM-2PM technique made it possible to monitor activity of over tens to hundreds neurons simultaneously. GrC activity depended on the number of spikes in the input mossy fiber bursts. PC and molecular layer interneuron activity paralleled that in the underlying GrC population revealing the spread of activity through the cerebellar cortical network. Moreover, circuit activity was increased by the GABA-A receptor blocker, gabazine, and reduced by the AMPA and NMDA receptor blockers, NBQX and APV. The SLM-2PM analysis of spatiotemporal patterns lent experimental support to the time-window and center-surround organizing principles of the granular layer.
Laboratory of Neurophysiology, Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Laboratory of Experimental and Computational Neurophysiology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia Modena, Italy.
Daniela
D
Gandolfi
Laboratory of Biophysics and Biophotonics, Department of Physics, University of Milano-Bicocca Milano, Italy.
Paolo
P
Pozzi
Laboratory of Neurophysiology, Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy.
Marialuisa
M
Tognolina
Laboratory of Biophysics and Biophotonics, Department of Physics, University of Milano-Bicocca Milano, Italy.
Giuseppe
G
Chirico
Laboratory of Experimental and Computational Neurophysiology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia Modena, Italy ; Laboratory of Neurophysiology, Brain Connectivity Center, C. Mondino National Neurological Institute, Fondazione IRCCS C. Mondino Pavia, Italy.
Jonathan
J
Mapelli
Laboratory of Neurophysiology, Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Laboratory of Neurophysiology, Brain Connectivity Center, C. Mondino National Neurological Institute, Fondazione IRCCS C. Mondino Pavia, Italy.
Egidio
E
D'Angelo
Purkinje cells; cerebellum; granule cells; two-photon microscopy