Enkephalinergic Control of Segmental Reflex Pathways and Descending Pathways in the Cat

1995 ◽  
pp. 435-442
Author(s):  
H. Steffens ◽  
U. Fronhöfer
Keyword(s):  
Descending Pathways ◽  
Reflex Pathways ◽  
Segmental Reflex

scholarly journals The Evaluation of “Spasticity”

1987 ◽  
Vol 14 (S3) ◽  
pp. 497-500 ◽  
Author(s):  
P. Ashby ◽  
A. Mailis ◽  
J. Hunter
Keyword(s):  
Motor Neuron ◽  
Past History ◽  
Muscle Mechanics ◽  
Muscle Length ◽  
Scoring Systems ◽  
Reflex Activity ◽  
Descending Pathways ◽  
Voluntary Activity ◽  
Reflex Pathways ◽  
Segmental Reflex

ABSTRACT:Lesions of the upper motor neuron cause: 1. Alterations in segmental reflex activity. For example increased tendon jerks and velocity dependent stretch reflexes ("spasticity"), clonus, the clasp knife response, release of flexion reflexes and extensor plantar reflexes. 2. Impaired ability to activate motoneurons rapidly and selectively. Voluntary movements may also be restrained by co-contraction of antagonists muscles, by segmental reflexes (enhanced during voluntary effort) or by contractures. A combination of these factors may impair overall functional ability. Segmental reflexes, voluntary power and overall functional abilities can be assessed using clinical scoring systems. Recordings of muscle length, tension andEMG offer more objective measures of reflex and voluntary activity and of overall functions such as locomotion, and can separate weakness from co-contraction, spasticity from contracture. Methods are now available for exploring individual (transmitter specific) segmental reflex pathways and descending pathways in man. Lesions of the upper motor neuron are complicated by secondary changes in segmental neurons. Segmental reflex activity and muscle mechanics depend on the immediate past history of events. These factors must be taken into account.

scholarly journals Segmental reflex pathways in spinal shock and spinal spasticity in man

1974 ◽  
Vol 37 (12) ◽  
pp. 1352-1360 ◽  
Author(s):  
P. Ashby ◽  
M. Verrier ◽  
E. Lightfoot
Keyword(s):  
Reflex Pathways ◽  
Spinal Shock ◽  
Segmental Reflex

Insights into mechanisms of intestinal segmentation in guinea pigs: a combined computational modeling and in vitro study

2008 ◽  
Vol 295 (3) ◽  
pp. G534-G541 ◽  
Author(s):  
Jordan D. Chambers ◽  
Joel C. Bornstein ◽  
Evan A. Thomas
Keyword(s):  
Guinea Pig ◽  
Computational Model ◽  
In Vitro Study ◽  
Afferent Pathway ◽  
Synaptic Coupling ◽  
Descending Pathways ◽  
Motor Patterns ◽  
Reflex Pathways ◽  
Vitro Model

Segmentation in the guinea pig small intestine consists of a number of discrete motor patterns including rhythmic stationary contractions that occur episodically at specific locations along the intestine. The enteric nervous system regulates segmentation, but the exact circuit is unknown. Using simple computer models, we investigated possible circuits. Our computational model simulated the mean neuron firing rate in the feedforward ascending and descending reflex pathways. A stimulus-evoked pacemaker was located in the afferent pathway or in a feedforward pathway. Output of the feedforward pathways was fed into a simple model to determine the response of the muscle. Predictions were verified in vitro by using guinea pig jejunum, in which segmentation was induced with luminal fatty acid. In the computational model, local stimuli produced an oral contraction and anal dilation, similar to in vitro responses to local distension, but did not produce segmentation. When the stimulus was distributed, representing a nutrient load, the result was either a tonic response or globally synchronized oscillations. However, when we introduced local variations in synaptic coupling, stationary contractions occurred around these locations. This predicts that severing the ascending and descending pathways will induce stationary contractions. An acute lesion in our in vitro model significantly increased the number of stationary contractions immediately oral and anal to the lesion. Our results suggest that spatially localized rhythmic contractions arise from a local imbalance between ascending excitatory and descending inhibitory muscle inputs and require a distributed stimulus and a rhythm generator in the afferent pathway.

scholarly journals Neuro-Ocular Release: A New Osteopathic Technique For Resolving Somatic Dysfunction

2020 ◽  
Vol 30 (2) ◽  
pp. 17-22
Author(s):  
Richard A. Feely ◽  
Jillian L. Smith
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Descending Pathways ◽  
Peripheral Tissues ◽  
Ocular Reflex ◽  
Reflex Pathways ◽  
Somatic Dysfunction ◽  
Osteopathic Treatment ◽  
Ascending Pathways ◽  
The Central Nervous System

Abstract Neuro-ocular release(NOR) is a new osteopathic treatment modality that can be used in conjunction with any indirect osteopathic technique. It is proposed that NOR utilizes the recruitment of the visual system to access the descending pathways, while counterstrain access the ascending pathways, resulting in a resetting of the central and peripheral nervous systems. This resetting allows for dampening of the potentiation of somatic dysfunction (SD). The ascending pathways integrate with many of the vision and ocular reflex pathways influencing the descending response to the peripheral tissues, the location of palpable somatic dysfunction. The authors purport the NOR technique allows for more time efficient and effective treatment by changing the central nervous system entrainment of SD.

Effects of spinal cord stimulation on segmental reflex pathways in man

Pain ◽  
1987 ◽  
Vol 30 ◽  
pp. S286
Author(s):  
J. P. Hunter ◽  
P. A. Ashby ◽  
P. G. Vanderlinden
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Stimulation ◽  
Reflex Pathways ◽  
Segmental Reflex

Peripheral reflex pathways involving abdominal viscera: transmission of impulses through prevertebral ganglia

1989 ◽  
Vol 256 (3) ◽  
pp. G581-G588 ◽  
Author(s):  
B. F. King ◽  
J. H. Szurszewski
Keyword(s):  
Nervous System ◽  
Distal Colon ◽  
Descending Pathways ◽  
Autonomic Ganglion ◽  
Reflex Pathways ◽  
Afferent Nerves ◽  
Prevertebral Ganglia ◽  
Mesenteric Ganglion ◽  
Pelvic Viscera ◽  
Vertebrate Central Nervous System

In neurophysiological terms, divergence describes the transmission of impulse traffic from a single afferent line, through an integrating nervous system, and out into multiple efferent lines. This feature has been ascribed to the vertebrate central nervous system and invertebrate ganglionic systems but has not yet been associated with the autonomic nervous system in mammals. Therefore, this study investigated the degree of divergence of afferent impulse traffic through a mammalian autonomic ganglion, the inferior mesenteric ganglion (IMG) in guinea pig. Multiunit discharges were recorded extracellularly from the peripheral nerves, which emerge from the IMG, to determine the lines of efferent outflow (i.e., divergence) of impulse traffic generated by stimulating central efferent and peripheral afferent nerves. Pathways interrupted by a cholinergic ganglion synapse were identified by using hexamethonium. Pathways running directly through the IMG were identified by studying the effects of dividing nerves surgically. A complex arrangement of ascending and descending pathways was revealed, showing a neural network that interconnects the upper gastrointestinal tract, distal colon, and pelvic viscera via prevertebral ganglia.

Neuromuscular Control of Movement

2018 ◽  
Keyword(s):  
Nervous System ◽  
Sensory Information ◽  
Neuromuscular Control ◽  
Complex Environments ◽  
Locomotor Rhythm ◽  
Motor Responses ◽  
Reflex Pathways ◽  
Local Reflex ◽  
Local Circuits ◽  
And Control

The control of movement is essential for animals traversing complex environments and operating across a range of speeds and gaits. We consider how animals process sensory information and initiate motor responses, primarily focusing on simple motor responses that involve local reflex pathways of feedback and control, rather than the more complex, longer-term responses that require the broader integration of higher centers within the nervous system. We explore how local circuits facilitate decentralized coordination of locomotor rhythm and examine the fundamentals of sensory receptors located in the muscles, tendons, joints, and at the animal’s body surface. These sensors monitor the animal’s physical environment and the action of its muscles. The sensory information is then carried back to the animal’s nervous system by afferent neurons, providing feedback that is integrated at the level of the spinal cord of vertebrates and sensory-motor ganglia of invertebrates.

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