A combinatorial approach to study synapses, circuits and retinal function
We utilize electrophysiological recording and functional imaging to assay neuronal function. We correlate single cell physiology with detailed anatomical analysis using light and electron microscopy. We take advantage of ultrastructural tools like serial block face SEM to map connectivity between cell types and construct wiring diagrams. We use genetic and viral tools to perturb cell function, express fluorescent probes and map circuits. This combinatorial approach allows us to dissect the molecular, anatomical and functional diversity of retinal circuits one element at a time.
- Two-photon functional imaging
- Labeling of neurons and receptors
- Serial Electron Microscopy
- Molecular Biology and genetic manipulations
We use patch clamp electrophysiology in whole mount retina as well as retinal slices to measure electrical responses from diverse cell types. We measure both synaptic inputs and neuronal output to examine synaptic physiology and circuit function. Our experimental designs especially cater to determining how visual signals are initiated in the photoreceptors and then transformed at different anatomical stages of the retinal circuit by cellular and synaptic mechanisms.
We use two-photon functional imaging in whole mount retina and slices for mapping light evoked responses from population of neurons. This method provides high spatial resolution and reasonable temporal resolution in monitoring activity in neuronal populations and their subcellular compartments.
We are interested in correlating physiology and function of retinal neurons with detailed knowledge about their morphology and synaptic inputs. We use two major techniques to label diverse cell types and study distribution of receptors and other molecules.
- Biolistic transfection
Movie: A midget ganglion cell imaged with a confocal microscope from the cell soma to its dendritic arbor. Dendrites masked out in blue. PSD-95, a marker for excitatory postsynaptic receptors in green; Inhibitory receptors (GABAa) labeled in red.
Understanding vision requires unraveling the circuit-level organization of the mammalian retina. Achieving this goal requires a detailed knowledge of the anatomical/synaptic connections between retinal neurons. To uncover the synaptic connectivity in the primate and mouse retina, my laboratory is using a Serial Block Face Scanning Electron Microscope (SBFSEM) in collaboration with other groups. This will provide a detailed connectivity map of the diverse visual pathways in the mammalian retina.
Our genetic strategies rely on cell-type specific recombinase expressing transgenic driver mouse lines and delivery of recombinant viruses to selectively target and express genetically encoded proteins.