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Shah PT, Valiante TA, Packer AM. Highly local activation of inhibition at the seizure wavefront in vivo. Cell Rep 2024; 43:114189. [PMID: 38703365 DOI: 10.1016/j.celrep.2024.114189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 12/22/2023] [Accepted: 04/17/2024] [Indexed: 05/06/2024] Open
Abstract
The propagation of a seizure wavefront in the cortex divides an intensely firing seizure core from a low-firing seizure penumbra. Seizure propagation is currently thought to generate strong activation of inhibition in the seizure penumbra that leads to its decreased neuronal firing. However, the direct measurement of neuronal excitability during seizures has been difficult to perform in vivo. We used simultaneous optogenetics and calcium imaging (all-optical interrogation) to characterize real-time neuronal excitability in an acute mouse model of seizure propagation. We find that single-neuron excitability is decreased in close proximity to the seizure wavefront but becomes increased distal to the seizure wavefront. This suggests that inhibitory neurons of the seizure wavefront create a proximal circumference of hypoexcitability but do not influence neuronal excitability in the penumbra.
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Affiliation(s)
- Prajay T Shah
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Taufik A Valiante
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada; Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada; Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Adam M Packer
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, UK.
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Gonzales DL, Khan HF, Keri HVS, Yadav S, Steward C, Muller LE, Pluta SR, Jayant K. A Translaminar Spacetime Code Supports Touch-Evoked Traveling Waves. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.09.593381. [PMID: 38766232 PMCID: PMC11100787 DOI: 10.1101/2024.05.09.593381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Linking sensory-evoked traveling waves to underlying circuit patterns is critical to understanding the neural basis of sensory perception. To form this link, we performed simultaneous electrophysiology and two-photon calcium imaging through transparent NeuroGrids and mapped touch-evoked cortical traveling waves and their underlying microcircuit dynamics. In awake mice, both passive and active whisker touch elicited traveling waves within and across barrels, with a fast early component followed by a variable late wave that lasted hundreds of milliseconds post-stimulus. Strikingly, late-wave dynamics were modulated by stimulus value and correlated with task performance. Mechanistically, the late wave component was i) modulated by motor feedback, ii) complemented by a sparse ensemble pattern across layer 2/3, which a balanced-state network model reconciled via inhibitory stabilization, and iii) aligned to regenerative Layer-5 apical dendritic Ca 2+ events. Our results reveal a translaminar spacetime pattern organized by cortical feedback in the sensory cortex that supports touch-evoked traveling waves. GRAPHICAL ABSTRACT AND HIGHLIGHTS Whisker touch evokes both early- and late-traveling waves in the barrel cortex over 100's of millisecondsReward reinforcement modulates wave dynamics Late wave emergence coincides with network sparsity in L23 and time-locked L5 dendritic Ca 2+ spikes Experimental and computational results link motor feedback to distinct translaminar spacetime patterns.
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Koek LA, Scholl B. Mirrored might: A vision for inhibition. Neuron 2024; 112:868-869. [PMID: 38513616 DOI: 10.1016/j.neuron.2024.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 02/27/2024] [Accepted: 02/27/2024] [Indexed: 03/23/2024]
Abstract
In this issue of Neuron, Znamenskiy et al.1 unveil functional connection specificity between PV+ inhibitory interneurons and excitatory pyramidal neurons in mouse visual cortex, providing a circuit mechanism for stable amplification of cortical subpopulations.
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Affiliation(s)
- Laura A Koek
- Department of Physiology and Biophysics, University of Colorado School of Medicine, 12800 East 19(th) Avenue, MS8307, Aurora, CO 80045, USA
| | - Benjamin Scholl
- Department of Physiology and Biophysics, University of Colorado School of Medicine, 12800 East 19(th) Avenue, MS8307, Aurora, CO 80045, USA.
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Ocana-Santero G, Packer AM, Sharp T, Butt SJB. In Vivo Two-Photon Microscopy Reveals Sensory-Evoked Serotonin (5-HT) Release in Adult Mammalian Neocortex. ACS Chem Neurosci 2024; 15:456-461. [PMID: 38251903 PMCID: PMC10853926 DOI: 10.1021/acschemneuro.3c00725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/09/2024] [Accepted: 01/16/2024] [Indexed: 01/23/2024] Open
Abstract
The recent development of genetically encoded fluorescent neurotransmitter biosensors has opened the door to recording serotonin (5-hydroxytryptamine, 5-HT) signaling dynamics with high temporal and spatial resolution in vivo. While this represents a significant step forward for serotonin research, the utility of available 5-HT biosensors remains to be fully established under diverse in vivo conditions. Here, we used two-photon microscopy in awake mice to examine the effectiveness of specific 5-HT biosensors for monitoring 5-HT dynamics in somatosensory cortex. Initial experiments found that whisker stimulation evoked a striking change in 5-HT biosensor signal. However, similar changes were observed in controls expressing green fluorescent protein, suggesting a potential hemodynamic artifact. Subsequent use of a second control fluorophore with emission peaks separated from the 5-HT biosensor revealed a reproducible, stimulus-locked increase in 5-HT signal. Our data highlight the promise of 5-HT biosensors for in vivo application, provided measurements are carried out with appropriate optical controls.
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Affiliation(s)
- Gabriel Ocana-Santero
- Department
of Pharmacology, University of Oxford, Oxford OX1 3QT, U.K.
- Department
of Physiology, Anatomy & Genetics, University
of Oxford, Oxford OX1 3PT, U.K.
| | - Adam M. Packer
- Department
of Physiology, Anatomy & Genetics, University
of Oxford, Oxford OX1 3PT, U.K.
| | - Trevor Sharp
- Department
of Pharmacology, University of Oxford, Oxford OX1 3QT, U.K.
| | - Simon J. B. Butt
- Department
of Physiology, Anatomy & Genetics, University
of Oxford, Oxford OX1 3PT, U.K.
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Zeng K, Jiao ZH, Jiang Q, He R, Zhang Y, Li WG, Xu TL, Chen Y. Genetically Encoded Photocatalysis Enables Spatially Restricted Optochemical Modulation of Neurons in Live Mice. ACS CENTRAL SCIENCE 2024; 10:163-175. [PMID: 38292609 PMCID: PMC10823520 DOI: 10.1021/acscentsci.3c01351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 02/01/2024]
Abstract
Light provides high temporal precision for neuronal modulations. Small molecules are advantageous for neuronal modulation due to their structural diversity, allowing them to suit versatile targets. However, current optochemical methods release uncaged small molecules with uniform concentrations in the irradiation area, which lack spatial specificity as counterpart optogenetic methods from genetic encoding for photosensitive proteins. Photocatalysis provides spatial specificity by generating reactive species in the proximity of photocatalysts. However, current photocatalytic methods use antibody-tagged heavy-metal photocatalysts for spatial specificity, which are unsuitable for neuronal applications. Here, we report a genetically encoded metal-free photocatalysis method for the optochemical modulation of neurons via deboronative hydroxylation. The genetically encoded photocatalysts generate doxorubicin, a mitochondrial uncoupler, and baclofen by uncaging stable organoboronate precursors. The mitochondria, nucleus, membrane, cytosol, and ER-targeted drug delivery are achieved by this method. The distinct signaling pathway dissection in a single projection is enabled by the dual optogenetic and optochemical control of synaptic transmission. The itching signaling pathway is investigated by photocatalytic uncaging under live-mice skin for the first time by visible light irradiation. The cell-type-specific release of baclofen reveals the GABABR activation on NaV1.8-expressing nociceptor terminals instead of pan peripheral sensory neurons for itch alleviation in live mice.
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Affiliation(s)
- Kaixing Zeng
- State
Key Laboratory of Chemical Biology, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 China
- School
of Physical Science and Technology, ShanghaiTech
University, 100 Haike Road, Shanghai 201210, China
| | - Zhi-Han Jiao
- Centre
for Brain Science and Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Qin Jiang
- Centre
for Brain Science and Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Ru He
- State
Key Laboratory of Chemical Biology, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 China
- School
of Physical Science and Technology, ShanghaiTech
University, 100 Haike Road, Shanghai 201210, China
| | - Yixin Zhang
- State
Key Laboratory of Chemical Biology, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 China
| | - Wei-Guang Li
- Centre
for Brain Science and Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
- Department
of Rehabilitation Medicine, Huashan Hospital, Institute for Translational
Brain Research, State Key Laboratory of Medical Neurobiology and Ministry
of Education Frontiers Centre for Brain Science, Fudan University, 131 Dongan Road, Shanghai 200032, China
| | - Tian-Le Xu
- Centre
for Brain Science and Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China
| | - Yiyun Chen
- State
Key Laboratory of Chemical Biology, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 China
- School
of Physical Science and Technology, ShanghaiTech
University, 100 Haike Road, Shanghai 201210, China
- School
of Chemistry and Material Sciences, Hangzhou Institute for Advanced
Study, University of Chinese Academy of
Sciences, Sub-lane Xiangshan, Hangzhou 310024, China
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