Neural Pathways Between Sacrocaudal Afferents and Lumbar Pattern Generators in Neonatal Rats

2003 ◽  
Vol 89 (2) ◽  
pp. 773-784 ◽  
Author(s):  
I. Strauss ◽  
A. Lev-Tov
Keyword(s):  
Spinal Cord ◽  
Nmda Receptors ◽  
Neural Control ◽  
Nmda Receptor Antagonist ◽  
Neural Pathways ◽  
Synaptic Activation ◽  
Neonatal Rats ◽  
Artificial Cerebrospinal Fluid ◽  
Pattern Generators ◽  
Lumbar Cord

Projections of sacrocaudal afferents (SCA) onto lumbar pattern generators were studied in isolated spinal cords of neonatal rats. A locomotor-like pattern could be produced by SCA stimulation in the majority of the preparations. The SCA-induced lumbar rhythm was abolished after blocking synaptic transmission in the sacrococcygeal (SC) cord by bathing its segments in a low-calcium, high-magnesium artificial cerebrospinal fluid and restored when the synaptic block was alleviated by local application of calcium onto specific SC segments prior to SCA stimulation. Thus the SCA evoked lumbar rhythm involves synaptic activation of relay neurons in the SC cord. Functional activation of these relays depends on non– N-methyl-d-aspartate (NMDA) receptors because the lumbar rhythm was abolished when the non-NMDA receptor antagonist CNQX was added to the SC cord. By contrast, pharmacological block of the rhythmicity in the SC cord by specific antagonists of NMDA receptors and α1 and α2 adrenoceptors did not impair the SCA-induced lumbar rhythm. Midsagittal splitting experiments of parts of the SC and lumbar cord revealed that crossed and uncrossed ascending/propriospinal pathways are coactivated by SCA stimulation. We suggest that these pathways ascend onto the thoracolumbar cord through the lateral, ventrolateral, and ventral funiculi, because a complete block of the lumbar rhythm could only be obtained with a bilateral interruption of all of these funiculi. The relevance of our findings to the neural control of the rhythmogenic networks in the spinal cord is discussed.

Orexin-induced feeding requires NMDA receptor activation in the perifornical region of the lateral hypothalamus

2007 ◽  
Vol 293 (3) ◽  
pp. R1022-R1026 ◽  
Author(s):  
Dolores F. Doane ◽  
Marcus A. Lawson ◽  
Jonathan R. Meade ◽  
Catherine M. Kotz ◽  
J. Lee Beverly
Keyword(s):  
Nmda Receptor ◽  
Food Intake ◽  
Nmda Receptors ◽  
Lateral Hypothalamus ◽  
Receptor Activation ◽  
Nmda Receptor Antagonist ◽  
Sprague Dawley ◽  
Orexin A ◽  
Sprague Dawley Rats ◽  
Artificial Cerebrospinal Fluid

Food intake is stimulated following administration of orexin-A into the perifornical region of the lateral hypothalamus (LH/PFA). Orexin neurons originating in the LH/PFA interact with a number of hypothalamic systems known to influence food intake, including glutamatergic neurons. Glutamatergic systems in the LH/PFA were demonstrated to initiate feeding through N-methyl-d-aspartic acid (NMDA) receptors. Male Sprague-Dawley rats fitted with brain guide cannulas to the LH/PFA were used in two experiments. In the first experiment, a combination microdialysis/microinjection probe was used to deliver artificial cerebrospinal fluid (aCSF) or 500 pmol of orexin-A into the LH/PFA. Orexin-A increased interstitial glutamate to 143 ± 12% of baseline ( P < 0.05), which remained elevated over the 120-min collection period. In the second experiment, the NMDA receptor antagonist d-2-amino-5-phosphonopentanoic acid (d-AP5; 10 nmol) was administered before orexin-A. The orexin-induced increase in food intake (from 1.1 ± 0.4 to 3.2 ± 0.5 g, P < 0.05) during the first hour was absent in rats receiving d-AP5 + orexin-A (1.2 ± 0.5 g). There was no effect of d-AP5 alone on food intake. These data support glutamatergic systems in the LH/PFA mediating the feeding response to orexin-A through NMDA receptors.

scholarly journals Features of hand-foot crawling behavior in human adults

2012 ◽  
Vol 107 (1) ◽  
pp. 114-125 ◽  
Author(s):  
M. J. MacLellan ◽  
Y. P. Ivanenko ◽  
G. Cappellini ◽  
F. Sylos Labini ◽  
F. Lacquaniti
Keyword(s):  
Spinal Cord ◽  
Neural Control ◽  
The Body ◽  
Bipedal Walking ◽  
Emg Activity ◽  
Gradual Transition ◽  
Spatiotemporal Pattern ◽  
Plantar Flexors ◽  
Pattern Generators ◽  
Hands And Feet

Interlimb coordination of crawling kinematics in humans shares features with other primates and nonprimate quadrupeds, and it has been suggested that this is due to a similar organization of the locomotor pattern generators (CPGs). To extend the previous findings and to further explore the neural control of bipedal vs. quadrupedal locomotion, we used a crawling paradigm in which healthy adults crawled on their hands and feet at different speeds and at different surface inclinations (13°, 27°, and 35°). Ground reaction forces, limb kinematics, and electromyographic (EMG) activity from 26 upper and lower limb muscles on the right side of the body were collected. The EMG activity was mapped onto the spinal cord in approximate rostrocaudal locations of the motoneuron pools to characterize the general features of cervical and lumbosacral spinal cord activation. The spatiotemporal pattern of spinal cord activity significantly differed between quadrupedal and bipedal gaits. In addition, participants exhibited a large range of kinematic coordination styles (diagonal vs. lateral patterns), which is in contrast to the stereotypical kinematics of upright bipedal walking, suggesting flexible coupling of cervical and lumbosacral pattern generators. Results showed strikingly dissimilar directional horizontal forces for the arms and legs, considerably retracted average leg orientation, and substantially smaller sacral vs. lumbar motoneuron activity compared with quadrupedal gait in animals. A gradual transition to a more vertical body orientation (increasing the inclination of the treadmill) led to the appearance of more prominent sacral activity (related to activation of ankle plantar flexors), typical of bipedal walking. The findings highlight the reorganization and adaptation of CPG networks involved in the control of quadrupedal human locomotion and a high specialization of the musculoskeletal apparatus to specific gaits.

Activation of NMDA receptors is required for the initiation and maintenance of walking-like activity in the mudpuppy (Necturus Maculatus)

2004 ◽  
Vol 82 (8-9) ◽  
pp. 637-644 ◽  
Author(s):  
Igor Lavrov ◽  
Jianguo Cheng
Keyword(s):  
Spinal Cord ◽  
Nmda Receptor ◽  
Nmda Receptors ◽  
Rhythmic Activity ◽  
Nmda Receptor Antagonist ◽  
Glycine Site ◽  
Burst Frequency ◽  
Selective Antagonist ◽  
Dependent Inhibition ◽  
Dose Dependent

We hypothesized that blocking the activation of N-methyl-D-aspartate (NMDA) receptors prevents the initiation of walking-like activity and abolishes the ongoing rhythmic activity in the spinal cord - forelimb preparation from the mudpuppy. Robust walking-like movements of the limb and rhythmic alternating elbow flexor–extensor EMG pattern characteristic of walking were elicited when continuous perfusion of the spinal cord with solution containing D-glutamate. The frequency of the walking-like activity was dose-dependent on the concentration of D-glutamate in the bath over a range of 0.2 to 0.9 mmol/L. Elevation of potassium concentrations failed to induce walking-like activity. Application of the selective antagonist 2-amino-5-phosphonovalerate (AP-5) produced dose-dependent block of the initiation and maintenance of walking-like activity induced by D-glutamate. Complete block of the activity was achieved when the concentration of AP-5 reached 20 µmol/L. Furthermore, application of L-701,324 (a selective antagonist of the strychnine-insensitive glycine site of NMDA receptor) (1–10 µmol/L) also resulted in complete block of the walking-like activity. In contrast, application of the non-NMDA receptor antagonist 6-cyno-7-nitroquinoxaline-2,3-dione (CNQX) (1–50 µmol/L) induced a dose-dependent inhibition of the burst frequency but failed to result in a complete block. Only at concentration as high as 100 µmol/L, did CNQX cause complete block of the rhythmic activity, presumably through nonspecific action on the strychnine-insensitive glycine site of NMDA receptors. These results suggest that activation of NMDA receptors is required for the initiation and maintenance of walking-like activity. Operation of non-NMDA receptors plays a powerful role in the modulation of the walking-like activity in the mudpuppy.Key words: locomotion, central pattern generator, spinal cord, mudpuppy, glutamate, glycine, N-methyl-D-aspartate (NMDA)-receptor, 2-amino-5-phosphonovalerate (AP-5), 6-cyno-7-nitroquinoxaline-2,3-dione (CNQX).

scholarly journals Reduction of food intake by cholecystokinin requires activation of hindbrain NMDA-type glutamate receptors

2011 ◽  
Vol 301 (2) ◽  
pp. R448-R455 ◽  
Author(s):  
Jason Wright ◽  
Carlos Campos ◽  
Thiebaut Herzog ◽  
Mihai Covasa ◽  
Krzysztof Czaja ◽  
...  
Keyword(s):  
Nmda Receptor ◽  
Food Intake ◽  
Nmda Receptors ◽  
Receptor Antagonist ◽  
Fourth Ventricle ◽  
Nmda Receptor Antagonist ◽  
Behavioral Pattern ◽  
Vagal Afferents ◽  
Nmda Receptor Antagonists ◽  
The Brain

Intraperitoneal injection of CCK reduces food intake and triggers a behavioral pattern similar to natural satiation. Reduction of food intake by CCK is mediated by vagal afferents that innervate the stomach and small intestine. These afferents synapse in the hindbrain nucleus of the solitary tract (NTS) where gastrointestinal satiation signals are processed. Previously, we demonstrated that intraperitoneal (IP) administration of either competitive or noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonists attenuates reduction of food intake by CCK. However, because vagal afferents themselves express NMDA receptors at both central and peripheral endings, our results did not speak to the question of whether NMDA receptors in the brain play an essential role in reduction of feeding by CCK. We hypothesized that activation of NMDA receptors in the NTS is necessary for reduction of food intake by CCK. To test this hypothesis, we measured food intake following IP CCK, subsequent to NMDA receptor antagonist injections into the fourth ventricle, directly into the NTS or subcutaneously. We found that either fourth-ventricle or NTS injection of the noncompetitive NMDA receptor antagonist MK-801 was sufficient to inhibit CCK-induced reduction of feeding, while the same antagonist doses injected subcutaneously did not. Similarly fourth ventricle injection of d-3-(2-carboxypiperazin-4-yl)-1-propenyl-1-phosphoric acid (d-CPPene), a competitive NMDA receptor antagonist, also blocked reduction of food intake following IP CCK. Finally, d-CPPene injected into the fourth ventricle attenuated CCK-induced expression of nuclear c-Fos immunoreactivity in the dorsal vagal complex. We conclude that activation of NMDA receptors in the hindbrain is necessary for the reduction of food intake by CCK. Hindbrain NMDA receptors could comprise a critical avenue for control and modulation of satiation signals to influence food intake and energy balance.

Activation of NMDA receptors drives action potentials in superficial dorsal horn from neonatal rats

Neuroreport ◽  
2000 ◽  
Vol 11 (8) ◽  
pp. 1721-1727 ◽  
Author(s):  
Rita Bardoni ◽  
Pier Cosimo Magherini ◽  
Amy B. MacDermott
Keyword(s):  
Nmda Receptors ◽  
Dorsal Horn ◽  
Action Potentials ◽  
Superficial Dorsal Horn ◽  
Neonatal Rats

scholarly journals Neuro-musculoskeletal Upper Limb in-silico as virtual patient

2021 ◽  
Author(s):  
Mallampalli Kapardi ◽  
Madhav Pithapuram ◽  
Raghu Seshadri Iyengar ◽  
Mandayam Rangayyan Yashaswini ◽  
Avinash Kumar Singh ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Upper Limb ◽  
In Silico ◽  
Neural Control ◽  
Early Stage ◽  
Cervical Spinal Cord ◽  
Human Movement ◽  
Virtual Patient ◽  
Spatio Temporal ◽  
Movement Simulation

Virtual patients and physiologies allow experimentation, design, and early-stage clinical trials in-silico. Virtual patient technology for human movement systems that encompasses musculoskeleton and its neural control are few and far in between. In this work, we present one such neuro-musculoskeletal upper limb in-silico model. This upper limb is both modular in architecture and generates movement as an emergent phenomenon out of a multiscale co-simulation of spinal cord neural control and musculoskeletal dynamics. It is developed on the NEUROiD movement simulation platform that enables a co-simulation of popular neural simulator NEURON and the musculoskeletal simulator OpenSim. In this work, we describe the design and development of the upper limb in a modular fashion, while reusing existing models and modules. We further characterize and demonstrate the use of this model in generating a range of commonly observed movements by means of a spatio temporal stimulation pattern delivered to the cervical spinal cord. We believe this work enables a first and small step towards an in-silico paradigms for understanding upper limb movement, disease pathology, medication, and rehabilitation. Index Terms : co-simulation, in-silico, NEUROiD, neuromusculoskeletal, upper limb, Virtual patient.

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