@article {69833,
	title = {Glutamate indicators with increased sensitivity and tailored deactivation rates},
	journal = {bioRxiv},
	year = {2025},
	month = {2025 Mar 20},
	abstract = {<p>Identifying the input-output operations of neurons requires measurements of synaptic transmission simultaneously at many of a neuron{\textquoteright}s thousands of inputs in the intact brain. To facilitate this goal, we engineered and screened 3365 variants of the fluorescent protein glutamate indicator iGluSnFR3 in neuron culture, and selected variants in the mouse visual cortex. Two variants have high sensitivity, fast activation (\&lt; 2 ms) and deactivation times tailored for recording large populations of synapses (iGluSnFR4s, 153 ms) or rapid dynamics (iGluSnFR4f, 26 ms). By imaging action-potential evoked signals on axons and visually-evoked signals on dendritic spines, we show that iGluSnFR4s/4f primarily detect local synaptic glutamate with single-vesicle sensitivity. The indicators detect a wide range of naturalistic synaptic transmission, including in the vibrissal cortex layer 4 and in hippocampal CA1 dendrites. iGluSnFR4 increases the sensitivity and scale (4s) or speed (4f) of tracking information flow in neural networks in vivo.</p>
},
	doi = {10.1101/2025.03.20.643984},
	url = {https://www.biorxiv.org/content/early/2025/03/24/2025.03.20.643984},
	author = {Aggarwal, Abhi and Negrean, Adrian and Chen, Yang and Iyer, Rishyashring and Reep, Daniel and Liu, Anyi and Palutla, Anirudh and Xie, Michael E. and MacLennan, Bryan J. and Hagihara, Kenta M. and Kinsey, Lucas W. and Sun, Julianna L. and Yao, Pantong and Zheng, Jihong and Tsang, Arthur and Tsegaye, Getahun and Zhang, Yonghai and Patel, Ronak H. and Arthur, Benjamin J. and Hiblot, Julien and Leippe, Philipp and Tarnawski, Miroslaw and Marvin, Jonathan S. and Vevea, Jason D. and Turaga, Srinivas C. and Tebo, Alison G. and Carandini, Matteo and Rossi, L. F. and Kleinfeld, David and Konnerth, Arthur and Svoboda, Karel and Turner, Glenn C. and Hasseman, Jeremy and Podgorski, Kaspar}
}
@article {69021,
	title = {Extracellular glutamate and GABA transients at the transition from interictal spiking to seizures.},
	journal = {Brain},
	year = {2023},
	month = {2023 Oct 03},
	abstract = {<p>Focal epilepsy is associated with intermittent brief population discharges (interictal spikes), which resemble sentinel spikes that often occur at the onset of seizures. Why interictal spikes self-terminate whilst seizures persist and propagate is incompletely understood. We used fluorescent glutamate and GABA sensors in an awake rodent model of neocortical seizures to resolve the spatiotemporal evolution of both neurotransmitters in the extracellular space. Interictal spikes were accompanied by brief glutamate transients which were maximal at the initiation site and rapidly propagated centrifugally. GABA transients lasted longer than glutamate transients and were maximal \~{}1.5 mm from the focus where they propagated centripetally. Prior to seizure initiation GABA transients were attenuated, whilst glutamate transients increased, consistent with a progressive failure of local inhibitory restraint. As seizures increased in frequency, there was a gradual increase in the spatial extent of spike-associated glutamate transients associated with interictal spikes. Neurotransmitter imaging thus reveals a progressive collapse of an annulus of feed-forward GABA release, allowing seizures to escape from local inhibitory restraint.</p>
},
	issn = {1460-2156},
	doi = {10.1093/brain/awad336},
	author = {Shimoda, Yoshiteru and Leite, Marco and Graham, Robert T and Marvin, Jonathan S and Hasseman, Jeremy and Kolb, Ilya and Looger, Loren L and Magloire, Vincent and Kullmann, Dimitri M}
}
