Long-term two-photon imaging of spinal cord in freely behaving mice

The spinal cord is critical to integrating peripheral information under sensory-guided motor behaviors in health and disease. However, the cellular activity underlie spinal cord function in freely behaving animals is not clear. Here, we developed a new method for imaging the spinal cord at cellular and subcellular resolution over weeks under naturalistic conditions. The method involves an improved surgery to reduce spinal movement, and the installation of a miniaturized two-photon microscope to obtain high-resolution imaging in moving mice. In vivo calcium imaging demonstrated that dorsal horn neurons show a sensorimotor program-dependent synchronization and heterogeneity under distinct cutaneous stimuli in behaving mice. The long-term imaging of sensory neurons revealed that in the spinal cord, healthy mice demonstrated stereotyped responses. However, in a neuropathic pain model, plasticity changes and neuronal sensitization were observed. We provide a practical method to study the function of spinal cord on sensory perception and disorders in freely behaving mice.

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In Vivo Two-Photon Imaging of Neurons and Glia in the Mouse Spinal Cord

Cold Spring Harbor Protocols ◽

10.1101/pdb.prot072264 ◽

2012 ◽

Vol 2012 (12) ◽

pp. pdb.prot072264-pdb.prot072264 ◽

Cited By ~ 5

Author(s):

H. Steffens ◽

F. Nadrigny ◽

F. Kirchhoff

Keyword(s):

Spinal Cord ◽

Mouse Spinal Cord ◽

Two Photon ◽

Photon Imaging ◽

Two Photon Imaging

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Spinal substance P release in vivo during the induction of long-term potentiation in dorsal horn neurons

Pain ◽

10.1016/s0304-3959(01)00414-6 ◽

2002 ◽

Vol 96 (1) ◽

pp. 49-55 ◽

Cited By ~ 39

Author(s):

Abdullahi Warsame Afrah ◽

Atle Fiskå ◽

Johannes Gjerstad ◽

Henrik Gustafsson ◽

Arne Tjølsen ◽

...

Keyword(s):

Substance P ◽

Dorsal Horn ◽

Long Term Potentiation ◽

Dorsal Horn Neurons ◽

P Release ◽

Term Potentiation ◽

Substance P Release

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Developmental Changes in the Fidelity and Short-Term Plasticity of GABAergic Synapses in the Neonatal Rat Dorsal Horn

Journal of Neurophysiology ◽

10.1152/jn.01342.2007 ◽

2008 ◽

Vol 99 (6) ◽

pp. 3144-3150 ◽

Cited By ~ 18

Author(s):

Rachel A. Ingram ◽

Maria Fitzgerald ◽

Mark L. Baccei

Keyword(s):

Spinal Cord ◽

Dorsal Horn ◽

Receptive Fields ◽

Neuronal Firing ◽

Neonatal Rat ◽

Superficial Dorsal Horn ◽

Short Term ◽

Dorsal Horn Neurons ◽

Gabaergic Synapses

The lower thresholds and increased excitability of dorsal horn neurons in the neonatal rat suggest that inhibitory processing is less efficient in the immature spinal cord. This is unlikely to be explained by an absence of functional GABAergic inhibition because antagonism of γ-aminobutyric acid (GABA) type A receptors augments neuronal firing in vivo from the first days of life. However, it is possible that more subtle deficits in GABAergic signaling exist in the neonate, such as decreased reliability of transmission or greater depression during repetitive stimulation, both of which could influence the relative excitability of the immature spinal cord. To address this issue we examined monosynaptic GABAergic inputs onto superficial dorsal horn neurons using whole cell patch-clamp recordings made in spinal cord slices at a range of postnatal ages (P3, P10, and P21). The amplitudes of evoked inhibitory postsynaptic currents (IPSCs) were significantly lower and showed greater variability in younger animals, suggesting a lower fidelity of GABAergic signaling at early postnatal ages. Paired-pulse ratios were similar throughout the postnatal period, whereas trains of stimuli (1, 5, 10, and 20 Hz) revealed frequency-dependent short-term depression (STD) of IPSCs at all ages. Although the magnitude of STD did not differ between ages, the recovery from depression was significantly slower at immature GABAergic synapses. These properties may affect the integration of synaptic inputs within developing superficial dorsal horn neurons and thus contribute to their larger receptive fields and enhanced afterdischarge.

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Central pattern generators in the brainstem and spinal cord: an overview of basic principles, similarities and differences

Reviews in the Neurosciences ◽

10.1515/revneuro-2017-0102 ◽

2019 ◽

Vol 30 (2) ◽

pp. 107-164 ◽

Cited By ~ 7

Author(s):

Inge Steuer ◽

Pierre A. Guertin

Keyword(s):

Spinal Cord ◽

Animal Models ◽

Central Pattern Generators ◽

Basic Principles ◽

Advanced Level ◽

Motor Behaviors ◽

Similarities And Differences ◽

Pattern Generators

AbstractCentral pattern generators (CPGs) are generally defined as networks of neurons capable of enabling the production of central commands, specifically controlling stereotyped, rhythmic motor behaviors. Several CPGs localized in brainstem and spinal cord areas have been shown to underlie the expression of complex behaviors such as deglutition, mastication, respiration, defecation, micturition, ejaculation, and locomotion. Their pivotal roles have clearly been demonstrated although their organization and cellular properties remain incompletely characterized. In recent years, insightful findings about CPGs have been made mainly because (1) several complementary animal models were developed; (2) these models enabled a wide variety of techniques to be used and, hence, a plethora of characteristics to be discovered; and (3) organizations, functions, and cell properties across all models and species studied thus far were generally found to be well-preserved phylogenetically. This article aims at providing an overview for non-experts of the most important findings made on CPGs inin vivoanimal models,in vitropreparations from invertebrate and vertebrate species as well as in primates. Data about CPG functions, adaptation, organization, and cellular properties will be summarized with a special attention paid to the network for locomotion given its advanced level of characterization compared with some of the other CPGs. Similarities and differences between these networks will also be highlighted.

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In vivo method of long-term perfusion of the central canal of the adult cat spinal cord for neurophysiological research

Bulletin of Experimental Biology and Medicine ◽

10.1007/bf00830266 ◽

1984 ◽

Vol 97 (1) ◽

pp. 130-131

Author(s):

Yu. S. Sverdlov ◽

T. Yu. Ruchinskaya

Keyword(s):

Spinal Cord ◽

Central Canal ◽

Adult Cat

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In vivo characterization of colorectal and cutaneous inputs to lumbosacral dorsal horn neurons in the mouse spinal cord

Neuroscience ◽

10.1016/j.neuroscience.2015.12.023 ◽

2016 ◽

Vol 316 ◽

pp. 13-25 ◽

Cited By ~ 5

Author(s):

K.E. Farrell ◽

M.M. Rank ◽

S. Keely ◽

A.M. Brichta ◽

B.A. Graham ◽

...

Keyword(s):

Spinal Cord ◽

Dorsal Horn ◽

Mouse Spinal Cord ◽

Dorsal Horn Neurons ◽

In Vivo Characterization

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Large-Scale Chronically Implantable Precision Motorized Microdrive Array for Freely Behaving Animals

Journal of Neurophysiology ◽

10.1152/jn.90687.2008 ◽

2008 ◽

Vol 100 (4) ◽

pp. 2430-2440 ◽

Cited By ~ 40

Author(s):

Jun Yamamoto ◽

Matthew A. Wilson

Keyword(s):

Single Unit ◽

Large Scale ◽

Neural Circuits ◽

Brain Regions ◽

Unit Recording ◽

Chronic Recording ◽

Large Numbers ◽

Freely Behaving

Multiple single-unit recording has become one of the most powerful in vivo electro-physiological techniques for studying neural circuits. The demand has been increasing for small and lightweight chronic recording devices that allow fine adjustments to be made over large numbers of electrodes across multiple brain regions. To achieve this, we developed precision motorized microdrive arrays that use a novel motor multiplexing headstage to dramatically reduce wiring while preserving precision of the microdrive control. Versions of the microdrive array were chronically implanted on both rats (21 microdrives) and mice (7 microdrives), and relatively long-term recordings were taken.

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Serotonin Increases the Incidence of Primary Afferent-Evoked Long-Term Depression in Rat Deep Dorsal Horn Neurons

Journal of Neurophysiology ◽

10.1152/jn.2001.85.5.1864 ◽

2001 ◽

Vol 85 (5) ◽

pp. 1864-1872 ◽

Cited By ~ 42

Author(s):

Sandra M. Garraway ◽

Shawn Hochman

Keyword(s):

Spinal Cord ◽

Dorsal Horn ◽

Long Term Potentiation ◽

Neonatal Rat ◽

Long Term Depression ◽

Primary Afferent ◽

Dorsal Horn Neurons ◽

Sensory Evoked ◽

Synaptic Responses

5-hydroxytryptamine (5-HT) is released in spinal cord by descending systems that modulate somatosensory transmission and can potently depress primary afferent-evoked synaptic responses in dorsal horn neurons. Since primary afferent activity-induced long-term potentiation (LTP) may contribute to central sensitization of nociception, we studied the effects of 5-HT on the expression of sensory-evoked LTP and long-term depression (LTD) in deep dorsal horn (DDH) neurons. Whole cell, predominantly current clamp, recordings were obtained from DDH neurons in transverse slices of neonatal rat lumbar spinal cord. The effect of 5-HT on dorsal-root stimulation-evoked synaptic responses was tested before, during, or after high-frequency conditioning stimulation (CS). In most cells (80%), 5-HT caused a depression of the naı̈ve synaptic response. Even though 5-HT depressed evoked responses, CS in the presence of 5-HT was not only still capable of inducing LTD but also increased its incidence from 54% in controls to 88% ( P < 0.001). Activation of ligands selective for 5-HT1A/1B and 5-HT1B, but not 5-HT2A/2C or 5-HT3receptors, best reproduced these actions. 5-HT also potently depressed postconditioning synaptic responses regardless of whether the induced plasticity was LTP or LTD. Our results demonstrate that in addition to depressing the amplitude of evoked sensory input, 5-HT can also control the direction of its long-term modifiability, favoring the expression of LTD. These findings demonstrate cellular mechanisms that may contribute to the descending serotonergic control of nociception.

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