Characterization of DTI Indices in the Cervical, Thoracic, and Lumbar Spinal Cord in Healthy Humans

The aim of this study was to characterizein vivomeasurements of diffusion along the length of the entire healthy spinal cord and to compare DTI indices, including fractional anisotropy (FA) and mean diffusivity (MD), between cord regions. The objective is to determine whether or not there are significant differences in DTI indices along the cord that must be considered for future applications of characterizing the effects of injury or disease. A cardiac gated, single-shot EPI sequence was used to acquire diffusion-weighted images of the cervical, thoracic, and lumbar regions of the spinal cord in nine neurologically intact subjects (19 to 22 years). For each cord section, FA versus MD values were plotted, and a k-means clustering method was applied to partition the data according to tissue properties. FA and MD values from both white matter (averageFA=0.69, averageMD=0.93×10−3 mm2/s) and grey matter (averageFA=0.44, averageMD=1.8×10−3 mm2/s) were relatively consistent along the length of the cord.

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Active Dendritic Integration of Inhibitory Synaptic Inputs In Vivo

Journal of Neurophysiology ◽

10.1152/jn.00521.2003 ◽

2003 ◽

Vol 90 (6) ◽

pp. 3617-3624 ◽

Cited By ~ 45

Author(s):

Jason J. Kuo ◽

Robert H. Lee ◽

Michael D. Johnson ◽

Heather M. Heckman ◽

C. J. Heckman

Keyword(s):

Spinal Cord ◽

Lumbar Spinal Cord ◽

Standard State ◽

Dendritic Integration ◽

Local Inhibition ◽

Highly Active ◽

Linear Integration ◽

Inward Currents ◽

Lumbar Spinal

Synaptic integration in vivo often involves activation of many afferent inputs whose firing patterns modulate over time. In spinal motoneurons, sustained excitatory inputs undergo enormous enhancement due to persistent inward currents (PICs) that are generated primarily in the dendrites and are dependent on monoaminergic neuromodulatory input from the brain stem to the spinal cord. We measured the interaction between dendritic PICs and inhibition generated by tonic electrical stimulation of nerves to antagonist muscles during voltage clamp in motoneurons in the lumbar spinal cord of the cat. Separate samples of cells were obtained for two different states of monoaminergic input: standard (provided by the decerebrate preparation, which has tonic activity in monoaminergic axons) and minimal (the chloralose anesthetized preparation, which lacks tonic monoaminergic input). In the standard state, steady inhibition that increased the input conductance of the motoneurons by an average of 38% reduced the PIC by 69%. The range of this reduction, from <10% to >100%, was proportional to the magnitude of the applied inhibition. Thus nearly linear integration of synaptic inhibition may occur in these highly active dendrites. In the minimal state, PICs were much smaller, being approximately equal to inhibition-suppressed PICs in the standard state. Inhibition did not further reduce these already small PICs. Overall, these results demonstrate that inhibition from local spinal circuits can oppose the facilitation of dendritic PICs by descending monoaminergic inputs. As a result, local inhibition may also suppress active dendritic integration of excitatory inputs.

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An in vivo method for recording single unit activity in lumbar spinal cord in mice anesthetized with a volatile anesthetic

Brain Research Protocols ◽

10.1016/j.brainresprot.2004.03.002 ◽

2004 ◽

Vol 13 (2) ◽

pp. 126-134 ◽

Cited By ~ 6

Author(s):

Jason M Cuellar ◽

Joseph F Antognini ◽

Earl Carstens

Keyword(s):

Spinal Cord ◽

Unit Activity ◽

Single Unit ◽

Volatile Anesthetic ◽

Lumbar Spinal Cord ◽

Single Unit Activity ◽

Lumbar Spinal

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Characterization of the hemodynamic response in the rat lumbar spinal cord using intrinsic optical imaging and laser speckle

Journal of Neuroscience Methods ◽

10.1016/j.jneumeth.2010.06.012 ◽

2010 ◽

Vol 191 (2) ◽

pp. 151-157 ◽

Cited By ~ 9

Author(s):

Nicolas Brieu ◽

Eric Beaumont ◽

Simon Dubeau ◽

Julien Cohen-Adad ◽

Frederic Lesage

Keyword(s):

Spinal Cord ◽

Optical Imaging ◽

Hemodynamic Response ◽

Laser Speckle ◽

Lumbar Spinal Cord ◽

Lumbar Spinal

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Characterization of [3H]Rauwolscine binding to alpha2-adrenoceptor sites in the lumbar spinal cord of the cat: Comparison to such binding sites in the cat frontal cerebral cortex

Brain Research ◽

10.1016/0006-8993(86)91045-0 ◽

1986 ◽

Vol 368 (1) ◽

pp. 87-100 ◽

Cited By ~ 11

Author(s):

James R. Howe ◽

Tony L. Yaksh

Keyword(s):

Spinal Cord ◽

Cerebral Cortex ◽

Binding Sites ◽

Lumbar Spinal Cord ◽

Frontal Cerebral Cortex ◽

Alpha2 Adrenoceptor ◽

Lumbar Spinal

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In Vivo Electrophysiology of Peptidergic Neurons in Deep Layers of the Lumbar Spinal Cord after Optogenetic Stimulation of Hypothalamic Paraventricular Oxytocin Neurons in Rats

International Journal of Molecular Sciences ◽

10.3390/ijms22073400 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3400

Author(s):

Daisuke Uta ◽

Takumi Oti ◽

Tatsuya Sakamoto ◽

Hirotaka Sakamoto

Keyword(s):

Spinal Cord ◽

Electrical Response ◽

Oxytocin Receptor ◽

Lumbar Spinal Cord ◽

Whole Cell ◽

Optogenetic Stimulation ◽

Lumbar Spinal ◽

Whole Cell Recordings ◽

Stimulation Of

The spinal ejaculation generator (SEG) is located in the central gray (lamina X) of the rat lumbar spinal cord and plays a pivotal role in the ejaculatory reflex. We recently reported that SEG neurons express the oxytocin receptor and are activated by oxytocin projections from the paraventricular nucleus of hypothalamus (PVH). However, it is unknown whether the SEG responds to oxytocin in vivo. In this study, we analyzed the characteristics of the brain–spinal cord neural circuit that controls male sexual function using a newly developed in vivo electrophysiological technique. Optogenetic stimulation of the PVH of rats expressing channel rhodopsin under the oxytocin receptor promoter increased the spontaneous firing of most lamina X SEG neurons. This is the first demonstration of the in vivo electrical response from the deeper (lamina X) neurons in the spinal cord. Furthermore, we succeeded in the in vivo whole-cell recordings of lamina X neurons. In vivo whole-cell recordings may reveal the features of lamina X SEG neurons, including differences in neurotransmitters and response to stimulation. Taken together, these results suggest that in vivo electrophysiological stimulation can elucidate the neurophysiological response of a variety of spinal neurons during male sexual behavior.

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Spinal Laminae I-II Neurons in Rat Recorded In Vivo in Whole Cell, Tight Seal Configuration: Properties and Opioid Responses

Journal of Neurophysiology ◽

10.1152/jn.1999.82.6.3316 ◽

1999 ◽

Vol 82 (6) ◽

pp. 3316-3326 ◽

Cited By ~ 68

Author(s):

Alan R. Light ◽

Helen H. Willcockson

Keyword(s):

Lumbar Spinal Cord ◽

Opioid Agonist ◽

Whole Cell ◽

Nociceptive Neurons ◽

Lamina I ◽

Cell Recording ◽

Conductance Increase ◽

Lumbar Spinal

Using the in vivo whole cell recording procedure described previously, we recorded 73 neurons in laminae I and II in the lumbar spinal cord of the rat. Input impedances averaged 332 MΩ, which indicated that prior sharp electrode recordings contained a significant current shunt. Characterization of the adequate stimuli from the excitatory hindlimb receptive field indicated that 39 of 73 neurons were nociceptive, 6 were innocuous cooling cells, 20 responded maximally to brush, and 8 cells were not excited by stimulation of the skin of the hindlimb. The locations of 15 neurons were marked with biocytin. Nociceptive neurons were mostly found in lamina I and outer II, cooling cells in lamina I, and innocuous mechanoreceptive cells were mostly found in inner II or in the overlying white matter. The μ-opioid agonist [d-Ala2, N-Me-Phe4, Gly5-ol]-Enkephalin (DAMGO) hyperpolarized 7 of 19 tested neurons with a conductance increase. This hyperpolarization was reversed by naloxone in the neurons in which it was applied. DAMGO also decreased the frequency of spontaneous PSPs in 13 neurons, 7 of which were also hyperpolarized by DAMGO. Five of the seven hyperpolarized neurons were nociceptive, responding to both heat and mechanically noxious stimuli, whereas two responded to slow, innocuous brush. These results indicate that whole cell, tight seal recordings sample a similar population of lamina I and II neurons in the rat as those found with sharp electrode recordings in cat and monkey. They further indicate that DAMGO hyperpolarizes a subset of the nociceptive neurons that have input from both heat and mechanical nociceptors and that presynaptic DAMGO effects can be observed in nociceptive neurons that are not hyperpolarized by DAMGO.

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Involvement of cannabinoid type 1 receptor in fasting-induced analgesia

Molecular Pain ◽

10.1177/1744806920969476 ◽

2020 ◽

Vol 16 ◽

pp. 174480692096947

Author(s):

Jeong-Yun Lee ◽

Grace J. Lee ◽

Ayumi Nakamura ◽

Pa Reum Lee ◽

Yeajin Kim ◽

...

Keyword(s):

Spinal Cord ◽

Endocannabinoid System ◽

Lumbar Spinal Cord ◽

Peripheral Tissues ◽

Cannabinoid Type 1 Receptor ◽

Analgesic Effects ◽

Sr 141716 ◽

Lumbar Spinal

The endocannabinoid system (ECS) is known to modulate not only food intake but also pain, especially via the cannabinoid type 1 receptor (CB1R) expressed throughout the central nervous system and the peripheral tissues. Our previous study demonstrated that fasting produces an analgesic effect in adult male mice, which is reversed by intraperitoneal (i.p.) administration of CB1R antagonist (SR 141716). In the present study, we further examined the effect of CB1R expressed in the peripheral tissues. In the formalin-induced inflammatory pain model, i.p. administration of peripherally restricted CB1R antagonist (AM 6545) reversed fasting-induced analgesia. However, intraplantar administration of SR 141716 did not affect fasting-induced analgesia. Furthermore, mRNA expression of CB1R did not change in the formalin model by fasting in the dorsal root ganglia. The formalin-induced c-Fos expression at the spinal cord level was not affected by fasting, and in vivo recording from the superficial dorsal horn of the lumbar spinal cord revealed that fasting did not affect formalin-induced neural activity, which indicates minimal involvement of the spinal cord in fasting-induced analgesia. Finally, when we performed subdiaphragmatic vagotomy to block the hunger signal from the gastrointestinal (GI) system, AM 6545 did not affect fasting-induced analgesia, but SR 141716 still reversed fasting-induced analgesia. Taken together, our results suggest that both peripheral and central CB1Rs contribute to fasting-induced analgesic effects and the CB1Rs in the GI system which transmit fasting signals to the brain, rather than those in the peripheral sensory neurons, may contribute to fasting-induced analgesic effects.

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In Vivo Recording of Nerve Conduction Velocity of Spinal CNS Fibers in the Mouse

Physiological Research ◽

10.33549/physiolres.933489 ◽

2017 ◽

pp. 545-548

Author(s):

P. DIBAJ ◽

E. D. SCHOMBURG

Keyword(s):

Spinal Cord ◽

Conduction Velocity ◽

Nerve Conduction ◽

Nerve Conduction Velocity ◽

Compound Action Potential ◽

Lumbar Spinal Cord ◽

Measured Distance ◽

Spinal Cord Level ◽

Lumbar Spinal

Anesthetic and surgical procedures and an electrophysiological method were developed for recording nerve conduction velocity (NCV) of CNS fibers in the murine spinal cord. Under intravenous anesthesia and artificial ventilation the lumbar spinal cord segments L1 to L4 and dorsal roots L3 to L5 on the left side were exposed by laminectomy. After stimulation of the dorsal root L4, a compound action potential (CAP) was recorded at the ipsilateral left fasciculus gracilis at the spinal cord level L1. The latency from stimulation to the CAP together with the measured distance between the electrodes was used for the determination of the NCV. NCV of the fastest fibers in the fasciculus gracilis was observed to be approximately 28 m/s. Reversible decrease of the NCV was measured, in vivo, under general hypothermia. The technique described serves for in vivo electrophysiological investigations of spinal central fibers in wildtype and mutant mice.

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Effects of Glutamate andγ-Aminobutyric Acid on Spontaneously Active Intraocular Spinal Cord Graft Neurons

Journal of Neural Transplantation and Plasticity ◽

10.1155/np.1991.101 ◽

1991 ◽

Vol 2 (2) ◽

pp. 101-111

Author(s):

J. G. Broton ◽

R. P. Yezierski ◽

Å. Seiger

Keyword(s):

Spinal Cord ◽

Firing Rate ◽

Gaba Receptor ◽

Aminobutyric Acid ◽

Lumbar Spinal Cord ◽

Adult Rat ◽

Fetal Rat ◽

Single Unit Recordings ◽

Lumbar Spinal

Pieces of fetal rat lumbar spinal cord were transplanted into the anterior eye chamber of adult rat hosts. At least seven months later, extracellular single-unit recordings of spontaneously active graft neurons were made prior to and during the superfusion of either glutamate orγ-aminobutyric acid (GABA). Superfusion of glutamate produced an increase (five cells), decrease (three cells), or had no effect (two cells) on the firing rate of neurons tested. Superfusion of GABA decreased the firing rate of all twelve neurons tested, while superfusion of the GABA receptor antagonist bicuculline increased the firing rates of all eight neurons tested. The latency and magnitude of the responses to glutamate and GABA were not related to depth of the recording electrode below the graft surface. Together, these data suggest that the intraocular spinal cord graft is suitable for thein vivostudy of GABA and glutamate neuropharmacology.

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