Imaging spinal cord activity in behaving animals

Nelson, Nicholas A.; Wang, Xiang; Cook, Daniela; Carey, Erin M.; Nimmerjahn, Axel

doi:10.1016/j.expneurol.2019.112974

Cited by 28 publications

(48 citation statements)

References 136 publications

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“…The main drawbacks associated with these systems are their limited spatial resolution and depth of field, as well as a limited single‐photon/colour excitation and the impossibility of moving the lens during imaging. These drawbacks will undoubtedly be addressed in the near future and should render integrated microscopes as widespread, complementary tools to two‐photon excitation systems mainly for the study of the brain and the spinal cord (Paukert & Bergles, 2012; Sekiguchi et al ., 2016; Nelson et al ., 2019).…”

Section: Animal Restraint and Tissue Immobilizationmentioning

confidence: 99%

Multiphoton intravital microscopy in small animals: motion artefact challenges and technical solutions

Soulet

Lamontagne‐Proulx

Aubé

et al. 2020

Journal of Microscopy

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Summary Since its invention 29 years ago, two‐photon laser‐scanning microscopy has evolved from a promising imaging technique, to an established widely available imaging modality used throughout the biomedical research community. The establishment of two‐photon microscopy as the preferred method for imaging fluorescently labelled cells and structures in living animals can be attributed to the biophysical mechanism by which the generation of fluorescence is accomplished. The use of powerful lasers capable of delivering infrared light pulses within femtosecond intervals, facilitates the nonlinear excitation of fluorescent molecules only at the focal plane and determines by objective lens position. This offers numerous benefits for studies of biological samples at high spatial and temporal resolutions with limited photo‐damage and superior tissue penetration. Indeed, these attributes have established two‐photon microscopy as the ideal method for live‐animal imaging in several areas of biology and have led to a whole new field of study dedicated to imaging biological phenomena in intact tissues and living organisms. However, despite its appealing features, two‐photon intravital microscopy is inherently limited by tissue motion from heartbeat, respiratory cycles, peristalsis, muscle/vascular tone and physiological functions that change tissue geometry. Because these movements impede temporal and spatial resolution, they must be properly addressed to harness the full potential of two‐photon intravital microscopy and enable accurate data analysis and interpretation. In addition, the sources and features of these motion artefacts are varied, sometimes unpredictable and unique to specific organs and multiple complex strategies have previously been devised to address them. This review will discuss these motion artefacts requirement and technical solutions for their correction and after intravital two‐photon microscopy.

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Section: Animal Restraint and Tissue Immobilizationmentioning

confidence: 99%

Multiphoton intravital microscopy in small animals: motion artefact challenges and technical solutions

Soulet

Lamontagne‐Proulx

Aubé

et al. 2020

Journal of Microscopy

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“…However, these techniques have been restricted to the study of superficial brain regions. Only very recently, has it become possible to image the activity of premotor and downstream motor circuits in the spinal cord of tethered, behaving mice [15,16], and in the ventral nerve cord (VNC) of tethered, behaving flies [17]. The VNC is coarsely organized like the mammalian spinal cord [18], and its control principles also resemble those used by vertebrates-including the roles of central pattern generators (CPGs) and limb mechanosensory feedback [19,20].…”

Section: Introductionmentioning

confidence: 99%

Long-term imaging of the ventral nerve cord in behaving adultDrosophila

Ramdya

Hermans

Kaynak

et al. 2021

Preprint

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The dynamics and connectivity of neural circuits continuously change during an animal's lifetime on timescales ranging from milliseconds to days. Therefore, to investigate how biological networks accomplish remarkable cognitive and behavioral tasks, minimally invasive methods are needed to perform repeated measurements, or perturbations of neural circuits in behaving animals across time. Such tools have been developed to investigate the brain but similar approaches are lacking for comprehensively and repeatedly recording motor circuits in behaving animals. Here we describe a suite of microfabricated technologies that enable long-term, minimally invasive optical recordings of the adult Drosophila melanogaster ventral nerve cord (VNC)---neural tissues that are functionally equivalent to the vertebrate spinal cord. These tools consist of (i) a manipulator arm that permits the insertion of (ii) a compliant implant into the thorax to expose the imaging region of interest; (iii) a numbered, transparent polymer window that encloses and provides optical access to the inside of the thorax, and (iv) a hinged remounting stage that allows gentle and repeated tethering of an implanted animal for two-photon imaging. We validate and illustrate the utility of our toolkit in several ways. First, we show that the thoracic implant and window have minimal impact on animal behavior and survival while also enabling neural recordings from individual animals across at least one month. Second, we follow the degradation of chordotonal organ mechanosensory nerve terminals in the VNC over weeks after leg amputation. Third, because our tools allow recordings of the VNC with the gut intact, we discover waves of neural population activity following ingestion of a high-concentration caffeine solution. In summary, our microfabricated toolkit makes it possible to longitudinally monitor anatomical and functional changes in premotor and motor neural circuits, and more generally opens up the long-term investigation of thoracic tissues.

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“…However, these approaches lack the spatiotemporal resolution, resilience against tissue movement, or cell-type specificity necessary to interrogate genetically defined cell types' activity patterns in behaving animals. In vivo fluorescence imaging overcomes many of these barriers by permitting high-speed, stable measurement of neuronal and non-neuronal activity in the spinal cord 2 .…”

Section: Introductionmentioning

confidence: 99%

“…Sensory stimuli can recruit cellular networks distributed across multiple spinal segments 2,3 (each ~1-1.5 mm rostra-caudal length in mice 4 ). Current fluorescence microscopes' optical properties hamper the high-speed measurement of such distributed activity.…”

Section: Introductionmentioning

confidence: 99%

“…Current fluorescence microscopes' optical properties hamper the high-speed measurement of such distributed activity. While cellular-resolution devices typically offer small fields of view (FOVs) covering less than one vertebra, large-FOV microscopes ("macroscopes") provide limited spatiotemporal resolution, sensitivity, and contrast, or are incompatible with use in freely moving mice 2,5,6 . Wearable widefield macroscopes with millimeter-sized FOV have recently been developed [7][8][9] .…”

Section: Introductionmentioning

confidence: 99%

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Trans-segmental imaging in the spinal cord of behaving mice

Shekhtmeyster

Duarte

Carey

et al. 2021

Preprint

Self Cite

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Spinal cord circuits play crucial roles in transmitting and gating cutaneous somatosensory modalities, such as pain, but the underlying activity patterns within and across spinal segments in behaving mice have remained elusive. To enable such measurements, we developed a wearable widefield macroscope with a 7.9 mm2 field of view, subcellular lateral resolution, 2.7 mm working distance, and <10 g overall weight. We show that highly localized painful mechanical stimuli evoke widespread, coordinated astrocyte excitation across multiple spinal segments.

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Imaging spinal cord activity in behaving animals

Cited by 28 publications

References 136 publications

Multiphoton intravital microscopy in small animals: motion artefact challenges and technical solutions

Multiphoton intravital microscopy in small animals: motion artefact challenges and technical solutions

Long-term imaging of the ventral nerve cord in behaving adultDrosophila

Trans-segmental imaging in the spinal cord of behaving mice

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