Differences in excitability properties between medial gastrocnemius, tibialis anterior, and abductor pollicis brevis motor axons

2017 ◽  
Vol 57 (1) ◽  
Author(s):  
Cliff S. Klein ◽  
Chen Ning Zhao ◽  
Hui Liu ◽  
Ping Zhou
Keyword(s):  
Tibialis Anterior ◽  
Medial Gastrocnemius ◽  
Motor Axons ◽  
Abductor Pollicis Brevis

The Correspondence Between Some Motor Points and Acupuncture Loci

1975 ◽  
Vol 03 (04) ◽  
pp. 347-358 ◽  
Author(s):  
Y. King Liu ◽  
Maria Varela ◽  
Robert Oswald
Keyword(s):  
Statistical Analysis ◽  
Tibialis Anterior ◽  
Double Blind Study ◽  
Vastus Medialis ◽  
Abductor Pollicis Brevis ◽  
Double Blind ◽  
Orbicularis Oculi ◽  
Peroneus Longus ◽  
Uv Illumination ◽  
Splenius Capitis

A double blind study was conducted to establish the possible correspondence between some motor points and acupuncture loci. THe protocol calls for the acupuncturist marking the first group of volunteers with invisible ink at the acupuncture loci. Then the motor points in the same volunteer are found by electrodiagnosis. The error is made visible by UV illumination. In the second group, the procedure is reversed. A statistical analysis of the error yields the following classes of correspondences: (a) Excellent: 1st Dorsal Interosseus (hand) = LI-4; Abductor Pollicis Brevis = Lu-10; Abductor Minimi Digiti = SI-4; 1st Dorsal Interosseus (foot)=LI-3; Tibialis Anterior = Curious Locus; Orbicularis Oculi = GB-I; Frontalis = GB-14; Splenius Capitis = GB-20; Sternocleidomastoid = LI-18; Semi-Spinalis Capitis = BI-10. (b) Good: Opponens Pollicis = Curious Locus; Peroneus Longus = Curious Locus; Flexior Digitorum Longus = Ki-3 (Ki-6); Trapezius (upper) = GB-21; Rectus Abdominis=Ki-15; Vastus Medialis = Sp-10.

Recurrent inhibition to and from motoneurons innervating the flexor digitorum and flexor hallucis longus muscles of the cat

1990 ◽  
Vol 63 (3) ◽  
pp. 395-403 ◽  
Author(s):  
T. M. Hamm
Keyword(s):  
Tibialis Anterior ◽  
Recurrent Inhibition ◽  
Medial Gastrocnemius ◽  
Flexor Hallucis Longus ◽  
Flexor Digitorum Longus ◽  
Lateral Gastrocnemius ◽  
Hindlimb Muscles ◽  
Inhibitory Postsynaptic Potentials ◽  
Flexor Digitorum ◽  
Stimulation Of

1. Recurrent inhibitory postsynaptic potentials (IPSPs) to and from motoneurons innervating the flexor digitorum longus (FDL) and flexor hallucis longus (FHL) muscles of the cat were investigated to determine whether recurrent inhibitory projections involving these motoneurons are similar--as would be consistent with the Ia and anatomic synergism of FDL and FHL--or are dissimilar, as are the activities of these muscles during locomotion (O'Donovan et al. 1982). 2. Composite recurrent IPSPs were recorded in several species of motoneurons innervating hindlimb muscles in response to stimulation of a number of muscle nerves in cats allowed to become unanesthetized after ischemic decapitation. 3. No recurrent IPSPs from stimulation of the FDL nerve were observed in motoneurons innervating FDL, FHL, lateral gastrocnemius-soleus (LG-S), medial gastrocnemius (MG), plantaris (Pl), tibialis anterior (TA), or extensor digitorum longus (EDL). 4. The recurrent IPSPs produced by stimulation of FHL were larger and found more frequently in LG-S than in FDL motoneurons. Recurrent inhibition from FHL was also greater in Pl than in FDL motoneurons. 5. The recurrent IPSPs produced by stimulation of LG-S, PL, and MG were larger in FHL than in FDL motoneurons, and those from LG-S and MG were found more frequently in FHL than in FDL motoneurons. 6. Stimulation of the TA nerve produces recurrent IPSPs in FDL but not in FHL motoneurons. A few FDL and FHL cells (6 of 23 and 9 of 34, respectively) received small (less than 0.5 mV) recurrent IPSPs from stimulation of the EDL nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

Average but not continuous speed match between motoneurons and muscle units of rat tibialis anterior

1993 ◽  
Vol 70 (4) ◽  
pp. 1300-1306 ◽  
Author(s):  
R. Bakels ◽  
D. Kernell
Keyword(s):  
Tibialis Anterior ◽  
Time Course ◽  
Muscle Fibers ◽  
Total Duration ◽  
Medial Gastrocnemius ◽  
Tetanic Force ◽  
Time To Peak ◽  
Time Courses ◽  
Isometric Twitch ◽  
Fatigue Sensitivity

1. Properties of single motoneuron/muscle-unit combinations were determined for tibialis anterior (TA) in rats anesthetized with pentobarbital. The TA observations were systematically compared with those obtained earlier by the use of the same techniques from rat medial gastrocnemius (MG). 2. TA motoneurons were investigated with regard to afterhyperpolarization (AHP; total duration 32-74 ms, amplitude 0.39-4.96 mV) and axonal conduction velocity (41-79 m/s). TA muscle-unit measurements included the time course of the isometric twitch (time-to-peak force 10.8-18.0 ms; total duration 42-92 ms), the maximum tetanic force (22-217 mN), and a measure of fatigue sensitivity (fatigue index 5-100%). The range of twitch and AHP durations ("speed range") was markedly smaller in the present TA material than for MG. 3. The mean duration of the TA motoneuronal AHP (49 +/- 8 ms, mean +/- SD) was close to that of its muscle-unit twitch (56 +/- 12 ms). Thus an "average" speed match existed between TA motoneurons and their muscle fibers. 4. For TA there was no correlation between the time courses of AHP and twitch. Thus there was for TA no "continuous" speed match between the motoneurons and their muscle fibers. 5. For TA twitches or AHPs studied separately, there was a significant correlation between different time course measures. Furthermore, compared with TA units having relatively fast twitches, those with slower twitches tended to show 1) a smaller maximum tetanic force and 2) a greater AHP amplitude. Fatigue-resistant units tended to have slower twitches than fatigue-sensitive ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunity to nerve growth factor and the effect on motor unit reinnervation in the rabbit

1992 ◽  
Vol 262 (5) ◽  
pp. R813-R818 ◽  
Author(s):  
D. I. Finkelstein ◽  
A. R. Luff ◽  
J. A. Schuijers
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neural Crest ◽  
Conduction Velocity ◽  
Motor Units ◽  
Medial Gastrocnemius ◽  
Afferent Neuron ◽  
Motor Axons ◽  
Nerve Growth ◽  
Myelin Thickness

The trophic effects of nerve growth factor (NGF) on sympathetic, peripheral afferent, and other neural crest-derived cells have been intensively investigated. More recently, NGF has been shown to have an influence on motoneurons. This study was undertaken to investigate whether NGF had any influence on the mechanical or histological properties of reinnervated motor units. Three groups of rabbits were used: normal rabbits, rabbits in which the nerve to medial gastrocnemius (MG) was cut and allowed to reinnervate for 56 days, and rabbits in which the MG nerve reinnervated in the presence of immunity to NGF. Immunity to NGF did not affect the ability of motor axons to reinnervate a muscle, nor were the contractile characteristics of the motor units altered. The size of horseradish peroxidase-labeled motoneurons was not influenced by immunization against NGF; however, the distribution of afferent neuron sizes was altered. Conduction velocity of motor axons proximal to the neuroma was significantly faster after immunization against NGF. Transection and subsequent reinnervation by a peripheral nerve normally causes an increase in myelin thickness proximal to the neuroma. However, immunization against NGF appeared to decrease the magnitude of myelin thickening. It was concluded that immunization against NGF affects motor axonal conduction velocity via an influence on the neural crest-derived Schwann cells.

Synaptic organization of defined motor-unit types in cat tibialis anterior

1980 ◽  
Vol 43 (6) ◽  
pp. 1631-1644 ◽  
Author(s):  
R. P. Dum ◽  
T. T. Kennedy
Keyword(s):  
Motor Unit ◽  
Tibialis Anterior ◽  
Muscle Afferents ◽  
Medial Gastrocnemius ◽  
Synaptic Organization ◽  
Ia Afferents ◽  
Group I ◽  
Ia Epsp ◽  
Group I Afferents ◽  
Stimulation Of

1. Synaptic potentials were recorded intracellularly in tibialis anterior (TA) motoneurons following stimulation of a descending brain stem pathway, the medial longitudinal fasciculus (MLF), and three segmental inputs, the homonymous and heteronymous group Ia afferents, the group I afferents from the antagonist, and the cutaneous and muscle afferents. Intracellular stimulation of the motoneurons was used to classify them, based on the properties of the innervated muscle units, into types FF, F(int), FR, and S (6, 16). 2. The sum of the monosynaptic EPSP amplitudes resulting from stimulation of homonymous and heteronymous group Ia afferents (summed group Ia EPSP) was inversely related to motoneuron size, as assessed by motoneuron input resistance, and was inversely related to motor-unit tetanic tension. Type-FF, -FR, and -S motoneurons showed significant differences in the mean amplitude of their summed group Ia EPSPs. 3. The amplitudes of disynaptic IPSPs resulting from stimulation of group I afferents in the antagonist muscle also showed an inverse relationship to motoneuron size. The observed relationships between motoneuron size and the monosynaptic group Ia EPSP amplitude or the disynaptic group I IPSP amplitude are compatible with the “size principle” of motor-unit recruitment (26). 4. The amplitudes of the monosynaptic EPSPs evoked in TA motoneurons by stimulation of the MLF were distributed rather randomly among all types of TA motoneurons. A slight tendency of larger monosynaptic EPSPs to occur in motoneurons with larger tetanic tensions was observed. 5. The polysynaptic effects from cutaneous and muscle afferents in sural and gastrocnemius-soleus nerves were frequently excitatory on type-FF motoneurons, but were primarily inhibitory on type-FR and -S motoneurons. Clearly, the polysynaptic cutaneous and muscle inputs and the monosynaptic MLF input onto TA motoneurons show a different pattern of synaptic organization than the group I inputs. 6. In general, the synaptic organization of the TA motor nucleus is similar to that of its extensor antagonist, medial gastrocnemius (MG) (2--5, 7, 8), when analogous neural circuits are compared. This parallel organization suggests a commonality of motor-control systems for both flexor and extensor muscles.

Dynamic Force Properties of Soleus, And Sensorimotor Interactions of Soleus, Medial Gastrocnemius, and Tibialis Anterior in the Freely Moving Cat

1997 ◽  
Vol 01 (02) ◽  
pp. 95-109 ◽  
Author(s):  
W. Herzog ◽  
T. R. Leonard
Keyword(s):  
Nerve Stimulation ◽  
Tibialis Anterior ◽  
Stance Phase ◽  
Tibialis Anterior Muscle ◽  
Force Production ◽  
Swing Phase ◽  
Medial Gastrocnemius ◽  
Active Force ◽  
Step Cycle ◽  
Sensorimotor Interactions

The dynamic properties of the cat soleus muscle were studied in freely walking animal preparations. The force and EMG responses of the soleus following supramaximal, ins tants of the step cycle. The sensorimotor interactions of soleus with the medial head of the gastrocnemius (a functional agonist of the soleus at the ankle) and the tibialis anterior (a functional antagonist of soleus at the ankle) were studied by measuring their force and EMG responses following the artifical stimulation of the soleus nerve. Supramaximal nerve stimulation showed distinct increases in the soleus forces during the entire swing phase and the second part (after peak forces had been reached) of the stance phase. Soleus forces could only be increased slightly in the first part of stance (from paw contact to peak force). These results suggest that force production of the soleus is virtually maximal during the early phases of stance but is submaximal for the remainder of the step cycle. Forces and EMGs of the medial gastrocnemius muscle were affected by the soleus nerve stimulation only in the latter part of the swing phase. In these cases, the force and EMG of the medial gastrocnemius were reduced significantly for the step cycle following the perturbation. The active force production of soleus during late swing causes an inhibition of medial gastrocnemius activity and force. Forces and EMGs of the tibialis anterior muscle were always affected by the soleus nerve stimulation during the swing phase of the step cycle. In these case, the force EMG of the medial gastrocnemius were reduced significantly for the step cycle following the perturbation. The active force production of soleus during late swing causes an inhibition of medial gastrocnemius activity and force. Forces and EMGs of the tibialis anterior muscle were always affected by the soleus nerve stimulation during the swing phase of the step cycle. In these instances, forces and EMGs of the tibialis anterior were significantly increased compared to step cycles preceding or following the perturbation. Part of the force enhancement is caused by the stretch of the activated tibialis anterior by the soleus, and part of the enhancement is caused by reflex activation. No effects on forces or EMGs of the tibialis anterior were observed when the soleus nerve stimulation showed its effects during the stance phase of the step cycle. The results of theis study suggest that the magnitude and the quality of ensorimotor interactions of soleus with medial gastrocnemius and tibialis anterior depend on the phase of the step cycle. The strongest interactions appear to exist during the swing phase; no observable interactions were found during stance.

Influence of Ankle Injury on Muscle Activation and Postural Control During Ballet Grand Plié

2014 ◽  
Vol 30 (1) ◽  
pp. 37-49 ◽  
Author(s):  
Chia-Wei Lin ◽  
Fong-Chin Su ◽  
Cheng-Feng Lin
Keyword(s):  
Lower Extremity ◽  
Tibialis Anterior ◽  
Muscle Activation ◽  
Center Of Pressure ◽  
Ankle Injury ◽  
Medial Gastrocnemius ◽  
Ankle Sprains ◽  
Activation Patterns ◽  
Temporal Muscle ◽  
Muscle Activation Patterns

Ballet deep squat with legs rotated externally (grand plié) is a fundamental movement for dancers. However, performing this task is a challenge to ankle control, particularly for those with ankle injury. Thus, the purpose of this study was to investigate how ankle sprains affect the ability of postural and muscular control during grand plié in ballet dancers. Thirteen injured dancers and 20 uninjured dancers performed a 15 second grand plié consisting of lowering, squatting, and rising phases. The lower extremity motion patterns and muscle activities, pelvic orientation, and center of pressure (COP) excursion were measured. In addition, a principal component analysis was applied to analyze waveforms of muscle activity in bilateral medial gastrocnemius, peroneus longus, and tibialis anterior. Our findings showed that the injured dancers had smaller pelvic motions and COP excursions, greater maximum angles of knee flexion and ankle dorsiflexion as well as different temporal activation patterns of the medial gastrocnemius and tibialis anterior. These findings suggested that the injured dancers coped with postural challenges by changing lower extremity motions and temporal muscle activation patterns.

Motoneuron and muscle-unit properties after long-term direct innervation of soleus muscle by medial gastrocnemius nerve in cat

1990 ◽  
Vol 64 (3) ◽  
pp. 847-861 ◽  
Author(s):  
R. C. Foehring ◽  
J. B. Munson
Keyword(s):  
Electrical Properties ◽  
Soleus Muscle ◽  
Previous Experiment ◽  
Muscle Fibers ◽  
Motor Units ◽  
Slow Muscle ◽  
Medial Gastrocnemius ◽  
Motor Axons ◽  
Lateral Gastrocnemius

1. This study addresses the following questions. 1) In a previous experiment, when the combined lateral gastrocnemius-soleus nerve was cross-innervated by the medial gastrocnemius (MG) nerve, was the predominance of slow muscle units in soleus muscle a result of selective routing of slow motor axons into soleus? 2) Is MG-nerve-induced conversion of soleus muscle fibers from slow to fast more complete at very long (18 mo vs. 9-11 mo) postoperative times? 3) Do MG motoneurons that cross-innervate soleus muscle recover their normal membrane electrical properties at very long postoperative times? 2. The proximal portion of approximately one-third of the MG nerve was coapted directly with the distally isolated soleus nerve. The MG muscle remained innervated by the unoperated portion of the MG nerve. At 6, 10, or 18 mos postoperative, motoneuron and/or muscle-unit properties were determined for MG motoneurons innervating MG, soleus, or neither muscle, and for axotomized soleus motoneurons. 3. In the partially denervated MG muscle, the proportions of motor units of each type were normal. This suggests that the population of MG motor axons that had been directed to the soleus nerve also contained a representative distribution of MG motoneuron types. 4. Most motor units (74%) in cross-innervated soleus (Xsoleus) were type S (based on muscle-unit contractile properties), in spite of the soleus nerve's having been cross-connected by approximately 75% fast MG motoneurons. Thus, even at very long postoperative times, slow soleus muscle units resisted conversion by fast MG motoneurons. 5. Thirty-two percent of MG motoneurons that had been cross-connected to soleus nerve elicited no measurable muscle contraction, compared with approximately 10% in previous reinnervation experiments in which the MG nerve was coapted with the MG or lateral gastrocnemius-soleus nerve. Thus MG motoneurons may be disadvantaged in their ability to innervate soleus muscle fibers. 6. It appears that at long postoperative times, those fast MG motoneurons tha had innervated large soleus muscle units had failed to convert those muscle fibers to fast types and had failed also to recover their normal motoneuron electrical properties. Conversion and recovery did occur for fast MG motoneurons that innervated small soleus muscle units and for slow MG motoneurons.

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