Understanding the complexities of information processing within the brain requires more than just knowing the precise neuronal wiring diagram, it also requires a detailed description of the temporal and spatial dynamics of signal flow between and within single neurons connected in a complex network. This daunting task is simplified by studying small groups of connected neurons, or microcircuits (1). A particularly attractive model microcircuit is that of the cerebellar cortex, because of its ordered, well-defined connectivity and small numbers of neuron types. Nevertheless, surprisingly little is known about how this microcircuit builds upon its well-known synaptic and cellular properties to dynamically integrate and process sensory information, largely because of the difficulty of measuring dynamic activity of many individual synapses or the ensuing postsynaptic signals in fine dendrites.

To overcome these challenges, my laboratory has combined optical and electrical recordings to tackle the challenges of studying dynamic neuronal computations within a canonical microcircuit, the cerebellar cortex. In order to control, monitor, and analyze information flow, we will employ state-of-the-art optical (ChR2-based photoactivation, rapid 3D two-photon (2P) imaging of dendritic Ca2+ and voltage, and neurotransmitter uncaging) and electrophysiological (in vivo whole-cell patch-clamp recording of neuronal responses to sensory stimuli) techniques. Several projects in the lab are focused on the development of advanced in vivo and super-resolution imaging strategies. Through collaborations we are also taking advantage of cutting-edge mathematical approaches to analysis of how biophysical properties of neurons lead to computations (Boolean functional analysis, reconstructed single-neuron and network modeling). Specifically, biological projects in the laboratory are focused on:  a) sensory-specific synaptic properties and integration at the input stage of cerebellar cortex, b) cellular mechanisms underlying dendritic computations by molecular layer interneurons, and c) general theoretical and experimental approaches to examine how dendritic computations participate in the processing of specific sensory features along the mossy fiber (MF) - granule cell (GC) – molecular layer interneuron (MLI) – Purkinje cell (PC) – axis of the cerebellar circuit. We hope to provide new and comprehensive insights into the neuronal computations, their underlying molecular and cellular mechanisms, and impact on microcircuit information processing.

Please see also: http://www.ura2182.cnrs-bellevue.fr/dni/

5 Selected Publications

Fink AE., Bender KJ., Trussell LO., Otis TS., and DiGregorio DA. (2012) Two-photon compatibility and single-voxel, single-trial detection of subthreshold neuronal activity by a two-component optical voltage sensor. PLoS One, 7 (8): e41434.

Abrahamsson T.,  Cathala L., Matsui K., Shigemoto R., and DiGregorio DA. (2012) Thin dendrites of cerebellar interneurons confer sublinear synaptic integration and a gradient of short-term plasticity. Neuron., 73 (6) : 1159-72.

DiGregorio DA. (2011) Confocal spot detection of presynaptic Ca2+ domains. In: Imaging in neuroscience: A laboratory manual (ed. Helmchen F, Konnerth A, Yuste R), 141-50. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY.

Bradley J., Luo R., Otis TS., and DiGregorio DA. (2009) Submillisecond optical reporting of membrane potential in situ using a neuronal tracer dye. J. Neurosci., 29 (29) : 9197–9209.

Lutz C., Otis T., DeSars V., Charpak S., DiGregorio DA., and Emiliani V. (2008) Holographic photolysis of caged neurotransmitters. Nat. Methods, 5(9): 821-7.

Awards, Fellowships and Honours

2012            AERS (evaluation: top score, A+)
2011            ANR Blanc: OpticNeuron (Coordinator)
2010            NERF Big equipment grant (Coordinator)
2009            ENP Collaborative Grant (Coordinator)
2009            AERS (evaluation: top score, A+)
2008            ANR Neuroscience: CalcSynFunc (Coordinator)
2008            ATIP Plus Award
2007            Federation pour la Recherche sur le Cerveau (FRC) Grant (Co-recipient)
2007            European Community Collaborative Grant on Photolysis
2006            Federation pour la Recherche sur le Cerveau (FRC) grant
2006            Bourse Fondation Fyssen
2005            Federation Recherche Medicale Grant
2005            ATIP grant for Young Independent Researchers
1999            UCLA Alumni Association Outstanding Graduate Student
1998            Hortense Fishbaugh Fellowship
1996            Nation Institutes of Health Individual Fellowship
1993            Nation Institutes of Health MD/Ph.D. (MSTP) Fellowship

• Cerebellar microcircuit function
• Synaptic and dendritic function
• In vivo and in situ optical detection of neuronal signaling (Ca2+ and voltage)
• Neuorotransmitter uncaging
• Super-resolution and 2-photon imaging