Neuronal activity underlying behavior is encoded by distinct populations comprising a myriad of excitatory and inhibitory cell classes. These populations not only form local networks in individual brain areas but also act concertedly with neural assemblies in other relevant brain areas via global connections that facilitate interareal communication. In my recent work, I developed a high-throughput protein engineering and voltage screening approach to create a suite of 4 mutually compatible fluorescent voltage indicators for recording neuronal activity at submillisecond precision. Using a novel dual-polarity, dual-color voltage imaging technique, these indicators enable concurrent optical recordings of the spiking dynamics of three distinct excitatory and interneuronal populations in the visual cortex or the hippocampus in running mice. In a parallel study, I used genetically encoded calcium indicators and a synchronized dual microscope system to uncover the concerted spatial and temporal odor patterning in the dorsal and previously inaccessible lateral regions of the olfactory bulb. Collectively, the multipopulation and multiareal recording approaches will empower studies of the interplay between local and global neural circuit dynamics underlying stimulus-guided behavior in awake animals.
- J Neurophysiol. 2023 Feb 1;129(2):431-444. Odor encoding by signals in the olfactory bulb.
- Science. 2022 Nov 4;378(6619):eabm8797. *equal contribution. . Dual-polarity voltage imaging of the concurrent dynamics of multiple neuron types.
- Baker KL, Vasan G, Gumaste A, V Pieribone VA, Verhagen JV. Spatiotemporal dynamics of odor responses in the lateral and dorsal olfactory bulb. PLoS Biology. 2019;17(9):e3000409.
- Gruber DF, Phillips BT, O'Brien R, Boominathan V, Veeraraghavan A, Vasan G, O'Brien P, Pieribone VA, Sparks JS. Bioluminescent ashes drive nighttime schooling behavior and synchronized swimming dynamics in flashlight fish. PloS ONE. 2019;14(8).
- Kannan M, Vasan G, Pieribone VA. Optimizing strategies for developing genetically encoded voltage indicators. Frontiers in Cellular Neuroscience. 2019;13:53
- Kannan M*, Vasan G*, Huang C, Haziza S, Li JZ, Inan H, Schnitzer MJ, Pieribone VA. Fast, in vivo voltage imaging using a red fluorescent indicator. Nature Methods. 2018;15(12):11081116. *equal contribution.
- Platisa J, Vasan G, Yang A, Pieribone VA. Directed evolution of key residues in uorescent protein inverses the polarity of voltage sensitivity in the genetically encoded indicator arclight. ACS Chemical Neuroscience. 2017;8(3):513523.
- Phillips BT, Gruber DF, Vasan G, Roman CN, Pieribone VA, Sparks JS. Observations of in situ deep-sea marine bioluminescence with a high-speed, high-resolution scmos camera. Deep Sea Research Part I: Oceanographic Research Papers. 2016;111:102109.
- Phillips BT, Gruber DF, Vasan G, Roman CN, Pieribone VA, Sparks JS, Roman CN. First evidence of bioluminescence on black smoker hydrothermal chimney. Oceanography. 2016;29(2):10.
- Lesser-Rojas L, Ebbinghaus P, Vasan G, Chu M, Erbe A, Chou C. Low-copy number protein detection by electrode nanogap-enabled dielectrophoretic trapping for surface enhanced raman spectroscopy and electronic measurements. Nano Letters. 2014;14(5):22422250.
- Vasan G, Erbe A. Incidence angle dependence of the enhancement factor in attenuated total reflection surface enhanced infrared absorption spectroscopy studied by numerical solution of the vectorial maxwell equations. Physical Chemistry Chemical Physics. 2012;14(42):1470214709.
- Gogoi M, Deb P, Vasan G, Keil P, Kostka A, Erbe A. Direct monophasic replacement of fatty acid by DMSA on SPION surface Applied Surface Science. 2012;258(24):96859691.