@article {69516, title = {Dynamic assemblies of parvalbumin interneurons in brain oscillations.}, journal = {Neuron}, year = {2024}, month = {2024 Jun 02}, abstract = {

Brain oscillations are crucial for perception, memory, and behavior. Parvalbumin-expressing (PV) interneurons are critical for these oscillations, but their population dynamics remain unclear. Using voltage imaging, we simultaneously recorded membrane potentials in up to 26 PV interneurons in\ vivo during hippocampal ripple oscillations in mice. We found that PV cells generate ripple-frequency rhythms by forming highly dynamic cell assemblies. These assemblies exhibit rapid and significant changes from cycle to cycle, varying greatly in both size and membership. Importantly, this variability is not just random spiking failures of individual neurons. Rather, the activities of other PV cells contain significant information about whether a PV cell spikes or not in a given cycle. This coordination persists without network oscillations, and it exists in subthreshold potentials even when the cells are not spiking. Dynamic assemblies of interneurons may provide a new mechanism to modulate postsynaptic dynamics and impact cognitive functions flexibly and rapidly.

}, issn = {1097-4199}, doi = {10.1016/j.neuron.2024.05.015}, author = {Huang, Yi-Chieh and Chen, Hui-Ching and Lin, Yu-Ting and Lin, Szu-Ting and Zheng, Qinsi and Abdelfattah, Ahmed S and Lavis, Luke D and Schreiter, Eric R and Lin, Bei-Jung and Chen, Tsai-Wen} } @article {68690, title = {Sensitivity optimization of a rhodopsin-based fluorescent voltage indicator}, journal = {Neuron}, volume = {111}, year = {2023}, month = {2023 May 17}, pages = {1547-1563}, abstract = {

The ability to optically image cellular transmembrane voltages at millisecond-timescale resolutions can offer unprecedented insight into the function of living brains in behaving animals. Here, we present a\ point mutation\ that increases the sensitivity of Ace2 opsin-based voltage indicators. We use the mutation to develop Voltron2, an improved chemigeneic voltage indicator that has a 65\% higher sensitivity to single APs and 3-fold higher sensitivity to subthreshold potentials than Voltron. Voltron2 retained the sub-millisecond kinetics and photostability of its predecessor, although with lower baseline fluorescence. In multiple\ in\ vitro\ and\ in\ vivo\ comparisons with its predecessor across multiple species, we found Voltron2 to be more sensitive to APs and subthreshold fluctuations. Finally, we used Voltron2 to study and evaluate the possible mechanisms of\ interneuron\ synchronization in the mouse hippocampus. Overall, we have discovered a generalizable mutation that significantly increases the sensitivity of Ace2 rhodopsin-based sensors, improving their voltage reporting capability.

}, issn = {08966273}, doi = {10.1016/j.neuron.2023.03.009}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0896627323002052}, author = {Abdelfattah, Ahmed S. and Zheng, Jihong and Singh, Amrita and Huang, Yi-Chieh and Reep, Daniel and Tsegaye, Getahun and Tsang, Arthur and Arthur, Benjamin J. and Rehorova, Monika and Olson, Carl V.L. and Shuai, Yichun and Zhang, Lixia and Fu, Tian-Ming and Milkie, Daniel E. and Moya, Maria V. and Weber, Timothy D. and Lemire, Andrew L. and Baker, Christopher A. and Falco, Natalie and Zheng, Qinsi and Grimm, Jonathan B. and Yip, Mighten C. and Walpita, Deepika and Chase, Martin and Campagnola, Luke and Murphy, Gabe J. and Wong, Allan M. and Forest, Craig R. and Mertz, Jerome and Economo, Michael N. and Turner, Glenn C. and Koyama, Minoru and Lin, Bei-Jung and Betzig, Eric and Novak, Ondrej and Lavis, Luke D. and Svoboda, Karel and Korff, Wyatt and Chen, Tsai-Wen and Schreiter, Eric R. and Hasseman, Jeremy P. and Kolb, Ilya} } @article {65081, title = {Bright and photostable chemigenetic indicators for extended in vivo voltage imaging.}, journal = {Science}, volume = {365}, year = {2019}, month = {2019 Aug 13}, pages = {699-704}, abstract = {

Imaging changes in membrane potential using genetically encoded fluorescent voltage indicators (GEVIs) has great potential for monitoring neuronal activity with high spatial and temporal resolution. Brightness and photostability of fluorescent proteins and rhodopsins have limited the utility of existing GEVIs. We engineered a novel GEVI, "Voltron", that utilizes bright and photostable synthetic dyes instead of protein-based fluorophores, extending the combined duration of imaging and number of neurons imaged simultaneously by more than tenfold relative to existing GEVIs. We used Voltron for in vivo voltage imaging in mice, zebrafish, and fruit flies. In mouse cortex, Voltron allowed single-trial recording of spikes and subthreshold voltage signals from dozens of neurons simultaneously, over 15 min of continuous imaging. In larval zebrafish, Voltron enabled the precise correlation of spike timing with behavior.

}, issn = {1095-9203}, doi = {10.1126/science.aav6416}, author = {Abdelfattah, Ahmed S and Kawashima, Takashi and Singh, Amrita and Novak, Ondrej and Liu, Hui and Shuai, Yichun and Huang, Yi-Chieh and Campagnola, Luke and Seeman, Stephanie C and Yu, Jianing and Zheng, Jihong and Grimm, Jonathan B and Patel, Ronak and Friedrich, Johannes and Mensh, Brett D and Paninski, Liam and Macklin, John J and Murphy, Gabe J and Podgorski, Kaspar and Lin, Bei-Jung and Chen, Tsai-Wen and Turner, Glenn C and Liu, Zhe and Koyama, Minoru and Svoboda, Karel and Ahrens, Misha B and Lavis, Luke D and Schreiter, Eric R} }