scholarly journals Fatigue in mammalian skeletal muscle stimulated under computer control

2001 ◽  
Vol 90 (1) ◽  
pp. 189-197 ◽  
Author(s):  
A. K. Wise ◽  
D. L. Morgan ◽  
J. E. Gregory ◽  
U. Proske
Keyword(s):  
Human Subjects ◽  
Computer Control ◽  
Limited Range ◽  
Medial Gastrocnemius ◽  
Mammalian Skeletal Muscle ◽  
Muscle Nerve ◽  
Computer Controlled ◽  
Postural Support ◽  
Medial Gastrocnemius Muscle ◽  
Stimulation Of

Functional electrical stimulation (FES) is used to provide paralyzed human subjects with postural support and a limited range of movements. Problems encountered with FES include jerky movements from tension oscillations during stimulation and rapid muscle fatigue. In this paper, we report experiments on anesthetized cats that test a new, computer-controlled method of stimulation of the muscle nerve supply, distributed across several inputs, which reduces these problems. After 5 min of continuous, distributed stimulation of the medial gastrocnemius muscle at 6 pulses per second (pps) across 6 channels, tension fell to 55.9 ± 3.9% (SE) of its original value. In comparison, after 5 min of synchronous stimulation of one muscle portion at 36 pps, tension fell to 11 ± 3.7%. At higher stimulation rates, 10 pps per channel (distributed) and 60 pps (synchronous), the differences in fatigue were even greater. Similar results were obtained when an intermittent, rather than a continuous, stimulation protocol was used. These findings indicate that distributed stimulation has important advantages over other methods for applications such as FES.

Rescue of motoneurons from the axotomized state by regeneration into a sensory nerve in cats

1991 ◽  
Vol 66 (5) ◽  
pp. 1462-1470 ◽  
Author(s):  
H. Nishimura ◽  
R. D. Johnson ◽  
J. B. Munson
Keyword(s):  
Electrical Stimulation ◽  
Electrical Properties ◽  
Sensory Nerve ◽  
Input Resistance ◽  
Cutaneous Nerve ◽  
Medial Gastrocnemius ◽  
Mechanical Activity ◽  
Muscle Nerve ◽  
Muscle Innervation ◽  
Stimulation Of

1. We studied the electrical properties of spinal motoneurons, the axons of which had regenerated into a cutaneous nerve. 2. In cats, all or part of the medial gastrocnemius (MG) muscle nerve was cut and directed distally into the caudal cutaneous sural (CCS) nerve, a sensory (primarily cutaneous) nerve. One or 2 yr later, electrical properties [conduction velocity (CV), rheobase (Irh), input resistance (RN), afterhyperpolarization (AHP), and excitatory postsynaptic potentials (EPSPs)] of MG motoneurons that had cross-regenerated into the CCS nerve were determined. These were compared with properties of normal and of axotomized MG motoneurons and with data from previous studies in which MG motoneurons had reinnervated their own or a foreign muscle. 3. Electrical stimulation of the MG-innervated CCS nerve produced no detected mechanical activity, indicating an absence of muscle innervation. Tactile stimulation of skin did not activate these motoneurons; i.e., they did not acquire properties of cutaneous afferents. 4. The CV and Irh of MG motoneurons axotomized 11 mo declined by 48 and 60%, respectively. 5. The CV of MG motoneurons that had regenerated through CCS was only slightly slower than normal, similar to that of MG motoneurons that reinnervated the “slow” muscle soleus (Foehring and Munson 1990). 6. The Irh and RN were also similar to those of MG motoneurons that had regenerated into the soleus muscle. 7. Electrical stimulation of the lateral gastrocnemius-soleus nerve generated EPSPs of normal or almost normal amplitude in MG motoneurons axotomized for 11 mo or cross-regenerated into CCS up to 2 yr.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo IIX and IIB fiber recruitment in gastrocnemius muscle of the rat is compartment related

1996 ◽  
Vol 81 (2) ◽  
pp. 933-942 ◽  
Author(s):  
C. J. De Ruiter ◽  
P. E. Habets ◽  
A. de Haan ◽  
A. J. Sargeant
Keyword(s):  
Cross Sections ◽  
Gastrocnemius Muscle ◽  
Periodic Acid ◽  
Medial Gastrocnemius ◽  
Periodic Acid Schiff ◽  
Fast Twitch ◽  
Medial Gastrocnemius Muscle ◽  
Stimulation Of

The purpose of the present study was to investigate to what extent fast-twitch IIX and IIB fiber recruitment was related to the natural existing muscle compartments (subvolumes of muscle innervated by different primary nerve branches) in rat medial gastrocnemius. Three groups (n = 6) of rats trotted on a motor-driven treadmill (20 degrees incline) at different speeds. A fourth group served as controls, and a fifth group received in situ electrical stimulation of all medial gastrocnemius muscle fibers. Postexercise glycogen levels (periodic acid-Schiff staining intensities) were made. Running caused more and in situ stimulation caused less glycogen breakdown in the proximal IIX and IIB fibers compared with the fibers of the same type in the most distal compartment. Furthermore, the boundaries of the most distal compartment could often be recognized in the periodic acid-Schiff-stained cross sections. It was concluded that during running the proximal IIX and IIB fibers were recruited to a greater extent (and at lower treadmill speeds) compared with the distal IIX and IIB fibers, respectively.

Applications of CCEM to Environmental Health Problems

1985 ◽  
Vol 43 ◽  
pp. 102-103
Author(s):  
R. J. Lee ◽  
J. S. Walker
Keyword(s):  
Electron Microscopy ◽  
Image Analysis ◽  
Environmental Health ◽  
Computer Control ◽  
External Agent ◽  
External Agents ◽  
Computer Controlled ◽  
Primitive State ◽  
Textural Changes ◽  
General Aspects

Electron microscopy (EM), with the advent of computer control and image analysis techniques, is rapidly evolving from an interpretative science into a quantitative technique. Electron microscopy is potentially of value in two general aspects of environmental health: exposure and diagnosis.In diagnosis, electron microscopy is essentially an extension of optical microscopy. The goal is to characterize cellular changes induced by external agents. The external agent could be any foreign material, chemicals, or even stress. The use of electron microscopy as a diagnostic tool is well- developed, but computer-controlled electron microscopy (CCEM) has had only limited impact, mainly because it is fairly new and many institutions lack the resources to acquire the capability. In addition, major contributions to diagnosis will come from CCEM only when image analysis (IA) and processing algorithms are developed which allow the morphological and textural changes recognized by experienced medical practioners to be quantified. The application of IA techniques to compare cellular structure is still in a primitive state.

The new CM-Series TEMs: integration of a five-axis motorized, fully computer-controlled goniometer

1993 ◽  
Vol 51 ◽  
pp. 258-259
Author(s):  
Marc J.C. de Jong ◽  
P. Emile S.J. Asselbergs ◽  
Max T. Otten
Keyword(s):  
Mechanical Design ◽  
Computer Control ◽  
Objective Lens ◽  
Access Port ◽  
Vibration Stability ◽  
Transmission Electron ◽  
Computer Controlled ◽  
High Degree ◽  
Five Axis ◽  
Five Axes

A new step forward in Transmission Electron Microscopy has been made with the introduction of the CompuStage on the CM-series TEMs: CM120, CM200, CM200 FEG and CM300. This new goniometer has motorization on five axes (X, Y, Z, α, β), all under full computer control by a dedicated microprocessor that is in communication with the main CM processor. Positions on all five axes are read out directly - not via a system counting motor revolutions - thereby providing a high degree of accuracy. The CompuStage enters the octagonal block around the specimen through a single port, allowing the specimen stage to float freely in the vacuum between the objective-lens pole pieces, thereby improving vibration stability and freeing up one access port. Improvements in the mechanical design ensure higher stability with regard to vibration and drift. During stage movement the holder O-ring no longer slides, providing higher drift stability and positioning accuracy as well as better vacuum.

The effect of long-term immobilization on the motor unit population of the cat medial gastrocnemius muscle

Neuroscience ◽  
1981 ◽  
Vol 6 (4) ◽  
pp. 725-739 ◽  
Author(s):  
R.F. Mayer ◽  
R.E. Burke ◽  
J. Toop ◽  
J.A. Hodgson ◽  
K. Kanda ◽  
...  
Keyword(s):  
Motor Unit ◽  
Gastrocnemius Muscle ◽  
Medial Gastrocnemius ◽  
Medial Gastrocnemius Muscle

Homosynaptic depression and transmitter turnover in spinal monosynaptic pathway

1977 ◽  
Vol 40 (1) ◽  
pp. 95-105 ◽  
Author(s):  
R. Capek ◽  
B. Esplin
Keyword(s):  
Transmitter Release ◽  
Motor Nerve ◽  
Drug Effects ◽  
Medial Gastrocnemius ◽  
Lateral Gastrocnemius ◽  
Homosynaptic Depression ◽  
Dorsal Root Reflex ◽  
Frequency Of Stimulation ◽  
Fractional Release ◽  
Stimulation Of

1. The transmission in the spinal monosynaptic pathway was studied during repetitive stimulation of a motor nerve by 10 stimuli at 2, 5, or 10 Hz in spinal cats. Initially, the amplitudes of the monosynaptic responses rapidly declined, reaching a plateau after a few stimuli. The level of the plateau was inversely related to the frequency of stimulation. 2. This depression of monosynaptic response was seen only when the same pathway was stimulated; the response elicited from the lateral gastrocnemius was not depressed when preceded by stimulation of the medial gastrocnemius nerve and vice versa. Pretreatment with semicarbazide left the homosynaptic depression unchanged while suppressing the dorsal root reflex. The participation of a depolarization of primary afferents in the described depression is, therefore, unlikely. 3. The decrease of transmitter release by successive volleys, which is the cause of the observed depression, could conceivably be related to the depletion of transmitter stores. 4. A procedure is described, based on this assumption, which allows the calculation of transmitter turnover. The input-output relation in the spinal monosynaptic pathway is used to convert the amplitudes of monosynaptic responses to the amounts of transmitter, both relative to the maximum response. The changes of transmitter release are analyzed under the assumption that each volley releases instantaneously a constant fraction of the transmitter store available for release and that this store is replenished at a constant fraction of the depleted part per second. 5. The values of fractional release per volley were about 0.4, irrespective of frequency of stimulation. 6. The values of fractional replenishment per second ranged from about 1 to 5 on the average, depending directly on the frequency of stimulation. 7. It is suggested that the described procedure might be useful in analyzing drug effects on synaptic transmission.

Sign in / Sign up

Export Citation Format

Share Document