scholarly journals Recruitment in a heterogeneous population of motor neurons that innervates the depressor muscle of the crayfish walking leg muscle

2008 ◽  
Vol 211 (4) ◽  
pp. 613-629 ◽  
Author(s):  
A. A. V. Hill ◽  
D. Cattaert
Keyword(s):  
Motor Neurons ◽  
Heterogeneous Population ◽  
Leg Muscle ◽  
Depressor Muscle

The Effect of Load on Locomotion in Crayfish

1981 ◽  
Vol 92 (1) ◽  
pp. 277-288 ◽  
Author(s):  
J. R. GROTE
Keyword(s):  
Motor Activity ◽  
Muscle Activity ◽  
Power Stroke ◽  
Step Cycle ◽  
Mechanical Advantage ◽  
Tendon Reflex ◽  
Leg Muscle ◽  
Depressor Muscle ◽  
Leg Movements ◽  
Load Conditions

Leg movements and leg muscle activity were monitored in unrestrained crayfish walking freely under several different load conditions. A variety of changes in the character of locomotion was found to vary with load including: (1) the timing and frequency of the step cycle and in particular the power stroke duration; (2) significant leg-positional changes which result in increased mechanical advantage under load; and (3) the (loadinduced) recruitment of the depressor muscle. In restrained, immobile animals, isometric loading of depression resulted in inhibition of motor activity in the depressor-remotor nerve, an effect similar to the vertebrate tendon reflex.

Cooperative Mechanisms Between Leg Joints of Carausius morosusI. Nonspiking Interneurons That Contribute to Interjoint Coordination

1998 ◽  
Vol 79 (6) ◽  
pp. 2964-2976 ◽  
Author(s):  
Dennis E. Brunn
Keyword(s):  
Membrane Potential ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Stick Insect ◽  
Interjoint Coordination ◽  
Antagonistic Muscle ◽  
Nonspiking Interneurons ◽  
Active Motor ◽  
Thoracic Part ◽  
Depressor Muscle

Brunn, Dennis E. Cooperative mechanisms between leg joints of Carausius morosus. I. Nonspiking interneurons that contribute to interjoint coordination. J. Neurophysiol. 79: 2964–2976, 1998. Three nonspiking interneurons are described in this paper that influence the activity of the motor neurons of three muscles of the proximal leg joints of the stick insect. Interneurons were recorded and stained intracellularly by glass microelectrodes; motor neurons were recorded extracellularly with oil-hook electrodes. The motor neurons innervate the two subcoxal muscles, the protractor and retractor coxae, and the thoracic part of the depressor trochanteris muscle. The latter spans the subcoxal joint before inserting the trochanter, thus coupling the two proximal joints mechanically. The three interneurons are briefly described here. First, interneuron NS 1 was known to become more excited during the swing phase of the rear and the stance phase of the middle leg. When depolarized it excited several motor neurons of the retractor coxae. This investigation revealed that it inhibits the activity of protractor and thoracic depressor motor neurons when depolarized as well. In a pilocarpine-activated animal, the membrane potential showed oscillations in phase with the activity of protractor motor neurons, suggesting that NS 1 might contribute to the transition from swing to stance movement. Second, interneuron NS 2 inhibits motor neurons of protractor and thoracic depressor when depolarized. In both a quiescent and a pilocarpine-activated animal, hyperpolarizing stimuli excite motor neurons of both muscles via disinhibition. In one active animal the disinhibiting stimuli were sufficient to generate swing-like movements of the leg. In pilocarpine-activated preparations the membrane potential oscillated in correlation with the motor neuronal activity of the protractor coxae and thoracic depressor muscle. Hyperpolarizing stimuli induced or reinforced the protractor and thoracic depressor bursts and inhibited the activity of the motor neurons of the retractor coxae muscle, the antagonistic muscle of the protractor. Therefore interneuron NS 2 can be regarded as an important premotor interneuron for the switching from stance to swing and from swing to stance. Finally, interneuron NS 3 inhibits the spontaneously active motor neurons of both motor neuron pools in the quiescent animal. During pilocarpine-induced protractor bursts, depolarizing stimuli applied to the interneuron excited several protractor motor neurons with large action potentials and one motor neuron of the thoracic depressor. No oscillations of the membrane potentials were observed. Therefore this interneuron might contribute to the generation of rapid leg movements. The results demonstrated that the two proximal joints are coupled not only mechanically but also neurally and that the thoracic part of the depressor appears to function as a part of the swing-generating system.

Androgen-induced plasticity at a “vocal” neuromuscular synapse

1994 ◽  
Vol 52 ◽  
pp. 32-33
Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman
Keyword(s):  
Xenopus Laevis ◽  
Motor Neurons ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Neuromuscular Synapse ◽  
Sexually Dimorphic ◽  
Intracellular Protein ◽  
Developmental Program ◽  
Androgen Action ◽  
Clawed Frog

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.

Effects of HBO with reduction of iNOS and HIF -1α in motor neurons after transient spinal cord ischemia in rabbits

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S452-S452
Author(s):  
Noritaka Murakami ◽  
Masahiro Sakurai ◽  
Takashi Horinouchi ◽  
Jun Ito ◽  
Shin Kurosawa ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Neurons ◽  
Spinal Cord Ischemia

Cardiovascular and Metabolic Responses to Electrical Stimulation-Induced Leg Exercise in Spinal Cord Injury

1997 ◽  
Vol 36 (04/05) ◽  
pp. 372-375 ◽  
Author(s):  
J. R. Sutton ◽  
A. J. Thomas ◽  
G. M. Davis
Keyword(s):  
Spinal Cord ◽  
Heart Rate ◽  
Spinal Cord Injury ◽  
Cardiac Output ◽  
Electrical Stimulation ◽  
Knee Flexion ◽  
Flexion Extension ◽  
Cord Injury ◽  
Leg Exercise ◽  
Leg Muscle

Abstract:Electrical stimulation-induced leg muscle contractions provide a useful model for examining the role of leg muscle neural afferents during low-intensity exercise in persons with spinal cord-injury and their able-bodied cohorts. Eight persons with paraplegia (SCI) and 8 non-disabled subjects (CONTROL) performed passive knee flexion/extension (PAS), electrical stimulation-induced knee flexion/extension (ES) and voluntary knee flexion/extension (VOL) on an isokinetic dynamometer. In CONTROLS, exercise heart rate was significantly increased during ES (94 ± 6 bpm) and VOL (85 ± 4 bpm) over PAS (69 ± 4 bpm), but no changes were observed in SCI individuals. Stroke volume was significantly augmented in SCI during ES (59 ± 5 ml) compared to PAS (46 ± 4 ml). The results of this study suggest that, in able-bodied humans, Group III and IV leg muscle afferents contribute to increased cardiac output during exercise primarily via augmented heart rate. In contrast, SCI achieve raised cardiac output during ES leg exercise via increased venous return in the absence of any change in heart rate.

Co-Culture of ES Cell-Derived Motor Neurons and Myotubes Show the Formation of Neuromuscular Junctions and Changes in Gene Expression

2006 ◽  
Vol 22 (06) ◽  
Author(s):  
Aleid Ruijs ◽  
Tateki Kubo ◽  
Jae Song ◽  
Milan Ranka ◽  
Mark Randolph ◽  
...  
Keyword(s):  
Gene Expression ◽  
Motor Neurons ◽  
Neuromuscular Junctions ◽  
Es Cell

Kontribusi Explosive Power Otot Tungkai Terhadap Hasil Lompat Jauh Gaya Jongkok Pada Mahasiswa Putra Prodi Pendidikan Kepelatihan Olahraga Semester II Universitas Riau

2015 ◽  
Vol 2 (2) ◽  
pp. 72
Author(s):  
Slamet ' ◽  
Ali Mandan ◽  
Ardiah Juita ◽  
Ridwan Sinurat
Keyword(s):  
Significant Relationship ◽  
Muscle Power ◽  
Test Results ◽  
Student Sample ◽  
Correlational Research ◽  
Explosive Power ◽  
Normality Test ◽  
Long Jump ◽  
Independent Variable ◽  
Leg Muscle

This study is correlational research that aims to find the contribution of leg muscleexplosive power to yield long jump squat style. The student sample was the son of varsity sportscoaching education Riau semester totaling 42 people. As the independent variable is theexplosive power leg muscle while dependent variable is the result of the long jump jongok style.Data (x) obtained from the test results without the leading long jump (standing board jump) toassess leg muscle explosive power while data (y) obtained from testing the long jump squat styleusing the prefix. Data were analyzed with statistical normality test is a test last lilifors alsoanalyzed the data to look for the correlation coefficient, and then proceed to test "t" after itsought the contribution. From the results of data processing for the normal distribution of dataobtained for the provision of data (x) and abnormally distributed in terms of data (y). r = 0.32,then through the test "t", t_ (count>) ttabel then there is a significant relationship between theexplosive muscle power with the outcome long jump squat style, via analysis of leg muscleexplosive power of determination have contributed 10.24% and 89 , 76% was contributed byother factors.

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