SEARCH · PubMed Health

Results for “Muscles”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources

PubMed1995

Respiratory muscle activity and oxygenation during sleep in patients with muscle weakness.

Patients with respiratory muscle weakness show nocturnal hypoventilation, with oxygen desaturation particularly during rapid eye movement (REM) sleep, but evidence in individuals with isolated bilateral diaphragmatic paresis (BDP) is conflicting. The effect of sleep on relative activity of the different respiratory muscles of such patients and, consequently, the precise mechanisms causing desaturation have not been clarified. We have studied eight patients, four with generalized muscle weakness and four with isolated BDP during nocturnal sleep with measurements including oxygen saturation and surface electromyographic (EMG) activity of various respiratory muscle groups. Nocturnal oxygenation correlated inversely with postural fall in vital capacity, an index of diaphragmatic strength. During REM sleep, hypopnoea and desaturation occurred particularly during periods of rapid eye movements (phasic REM sleep). In most subjects, such events were "central" in type and associated with marked suppression of intercostal muscle activity, but two subjects had recurrent desaturation due to "obstructive" hypopnoea and/or apnoea. Expiratory activity of the external oblique muscle was present whilst awake and during non-rapid eye movement (NREM) sleep in seven of the eight subjects in the semirecumbent posture. This probably represents an "accessory inspiratory" effect, which aids passive caudal diaphragmatic motion as the abdominal muscles relax at the onset of inspiration. Expiratory abdominal muscle activity was suppressed in phasic REM sleep, suggesting that loss of this "accessory inspiratory" effect may contribute to "central" hypopnoea. We conclude that, in patients with muscle weakness, nocturnal oxygenation correlates with diaphragmatic strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Electromyography↗

PubMedDate not supplied

Skeletal muscle architecture: implications for muscle function and surgical tendon transfer.

Skeletal muscles have mechanical properties that are well-described by the length-tension relationship (for isometric contractions) and the force-velocity relationship (for isotonic contractions). These two intrinsic properties are scaled for a given muscle based on its architectural properties. Muscle active force-generating range is determined by muscle fiber length, while maximum muscle force is determined by physiologic cross-sectional area. These and other architectural properties should be matched between muscles when planning surgical tendon transfers in order to closely match donor and recipient muscles. Finally, the fiber length/moment arm ratio of a muscle-joint combination must be considered when describing strength because strength is a manifestation of both muscle and joint properties and not either alone. Unfortunately, detailed description of normal musculoskeletal design or optimal transfer strategy cannot be made until more basic science studies of the musculoskeletal system are conducted.

Finger Injuries↗

PubMed1997

Stable integration of an mdx skeletal muscle cell line into dystrophic (mdx) skeletal muscle: evidence for stem cell status.

We have previously described a method for the derivation of long term cultures of undifferentiated myoblasts from the skeletal muscle of dystrophic (mdx) mice (J. Smith and P. N. Schofield, Exp. Cell Res., 210: 86-93, 1994). We now show that a clonal mdx-derived skeletal muscle cell line labeled with a retrovirus conferring beta-galactosidase activity and G418 resistance (PD50A) is capable of incorporation into mdx skeletal muscle myofibers for up to 14 months with no incidence of tumor formation. After a lag period of 5 days, injected PD50A cells disperse throughout the injected tibialis anterior muscle and take up satellite cell positions on the perimeter of myofiber bundles. PD50A cells begin to incorporate into fused muscle syncitium as early as 8 weeks after injection and persist for at least 14 months. We have rederived myoblasts expressing beta-galactosidase from PD50A-injected muscles 12 months after injection, demonstrating that a reserve of mononuclear proliferation-competent PD50A cells are present in host muscle up to a year after their original introduction. These data support the contention that myoblasts derived by this culture method are functionally representative of a class of skeletal muscle "stem cells" and thus have potential both as agents for cellular therapy of intransigent diseases such as Duchenne muscular dystrophy as well as being a useful tool for the further investigation of normal muscle development.

Animals↗

PubMed1997

Smooth muscle heterogeneity: does the striated muscle model apply?

Smooth muscle cells are the major component of most smooth muscle tissue. Although the function of these tissues is known to differ, it has been generally assumed that the smooth muscle cells that make up these tissues are all the same. In striated muscle, individual fibers composed of unique contractile and regulatory proteins have unique mechanical properties. Smooth muscles also contain unique proteins. The hexamer myosin has multiple isoforms of its heavy and light chain subunits. Some of these differences result from alternate splicing of a single gene, while others result from multiple genes. At the tissue level, the presence of these isoforms is developmentally regulated and varies between tissues and species. There are numerous contradictory reports in the literature regarding possible unique regulation and function for the multiple myosin heavy and light chain isoforms. By extending molecular and mechanical methods beyond their normally used ranges, we have begun a series of experiments at the single smooth muscle cell level. Preliminary results show extreme heterogeneity of myosin isoforms between smooth muscle cells. In addition, preliminary results suggest that the ratio of the SM1 and SM2 MHC tail isoforms do not correlate with unloaded shortening velocity. However, there is a good correlation between the amount of SM2 MHC isoform present in the cell and the minimum length to which the cell can shorten. Thus, cells with a greater SM2 content appear to shorten more than cells with a lesser SM2 content. As with striated muscle, single-cell experiments may be required to determine the unique function of protein isoforms in smooth muscle tissues.

Animals↗

PubMed1998

Muscle response to changing neuronal input in the lobster (Panulirus interruptus) stomatogastric system: slow muscle properties can transform rhythmic input into tonic output.

Slow, non-twitch muscles are widespread in lower vertebrates and invertebrates and are often assumed to be primarily involved in posture or slow motor patterns. However, in several preparations, including some well known invertebrate "model" preparations, slow muscles are driven by rapid, rhythmic inputs. The response of slow muscles to such inputs is little understood. We are investigating this issue with a slow stomatogastric muscle (cpv1b) driven by a relatively rapid, rhythmic neural pattern. A simple model suggests that as cycle period decreases, slow muscle contractions show increasing intercontraction temporal summation and at steady state consist of phasic contractions overlying a tonic contracture. We identify five components of these contractions: total, average, tonic, and phasic amplitudes, and percent phasic (phasic amplitude divided by total amplitude). cpv1b muscle contractions induced by spontaneous rhythmic neural input in vitro consist of phasic and tonic components. Nerve stimulation at varying cycle periods and constant duty cycle shows that a tonic component is always present, and at short periods the muscle transforms rhythmic input into almost completely tonic output. Varying spike frequency, spike number, and cycle period show that frequency codes total, average, and tonic amplitudes, number codes phasic amplitude, and period codes percent phasic. These data suggest that tonic contraction may be a property of slow muscles driven by rapid, rhythmic input, and in these cases it is necessary to identify the various contraction components and their neural coding. Furthermore, the parameters that code these components are interdependent, and control of slow muscle contraction is thus likely complex.

Action Potentials↗

PubMed1979

Occurrence and distribution of muscle spindles in masticatory and suprahyoid muscles of the rat.

The occurrence and distribution of muscle spindles was studied in histochemically and conventionally stained serial cross sections of 6-week-old and adult rat masticatory and suprahyoid muscles. Spindles were present in moderate to large numbers in jaw closers, but they were absent in jaw openers and two of four muscles of an accessory suprahyoid group. In jaw closers, 67% or more of the total spindle population was concentrated relatively distant from the temporomandibular joint, in muscle portions which contained large numbers of extrafusal fibers reacting strongly for oxidative enzymes. Because of their location, spindles in these portions should be stretched more and, subsequently, should respond with a greater afferent discharge at any given muscle length than spindles situated nearer to the joint. Spindles in jaw closers, especially the medial pterygoid and deep masseter, often occurred in clusters and complex forms near the terminal branching of intramuscular nerve trunks. No such concentrations were seen in the two muscles of the accessory suprahyoid group that had spindles. The association in jaw closers of spindles with extrafusal fibers high in oxidative enzyme activity is consistent with the view that spindles are the sensory component of a reflex system that recruits these fibers for finely-graded contractions in response to small internal length-changes of the muscle (Botterman et al., '78); however, in jaw openers and two muscles of the accessory suprahyoid group, the absence of spindles, coupled with the presence of large populations of extrafusal fibers high in oxidative enzyme activity, is not easily reconciled with this concept.

Animals↗

PubMed1982

Limitation of jaw movement by antagonist muscle stiffness during unloading of human jaw closing muscles.

The unloading reflex in the jaw closing muscles in man was investigated with a view to correlating the jaw closing movement with the timing of the electrical activity of the agonist and antagonist muscles. When the resistance to the forceful isometric bite was suddenly and unexpectedly withdrawn, the closing movement of the mandible was always arrested before the teeth came together. The rapid arrest of the jaw closing movement was not adequately accounted for by the timing of the inhibition of the jaw closing muscles and reflex excitation of the jaw opening muscles. It was observed that the jaw opening muscles, as well as the jaw closing muscles, were always active during the phase of isometric biting on an object between the teeth. It is therefore concluded that the resulting stiffness of the antagonist muscles is the mechanism which is principally responsible for limiting the jaw closing movement after unloading of the agonist muscles.

Adult↗

PubMed2003

Muscle- and fibre type-specific expression of glucose transporter 4, glycogen synthase and glycogen phosphorylase proteins in human skeletal muscle.

The muscle- and fibre type-specific expression of skeletal muscle glucose transporter 4 (GLUT4), glycogen synthase (GS) and glycogen phosphorylase (GP) was investigated in six young male subjects. Single muscle fibres were dissected from vastus lateralis (VL), soleus (SO) and triceps brachii (TB) muscle biopsy samples. On the basis of myosin heavy chain (MHC) expression, fibres were pooled into three groups (MHC I, MHC IIA and MHC IIX) and the GLUT4, GS and GP content of 15-40 pooled fibres determined using SDS-PAGE and immunological detection. In VL, the GLUT4 content in the pooled muscle fibres expressing MHC I was approximately 33% higher ( P<0.05) than in fibres expressing MHC IIA or IIX. There was no difference in GLUT4 content between fibres expressing MHC IIA or IIX, nor were there any differences in GS and GP content between any of the fibre types. In SO, there was no difference in GLUT4, GS and GP between fibres expressing MHC I or IIA. No fibres expressing type IIX were detected. In TB, fibres expressing MHC IIA and IIX had significantly ( P<0.05) more GP (66% and 55 % in MHC IIA and MHCIIX, respectively) than those expressing MHC I, whilst there was no difference in GP between MHC IIA and MHC IIX fibres. The GLUT4 and the GS content was similar in fibres expressing MHC I, IIA and IIX in the TB. Our data directly demonstrate that some proteins, like GLUT4 and GP, are expressed in a fibre type-specific manner in some, but not all, muscles, whilst other proteins, like GS, are not. In human skeletal muscle the GLUT4, GS and GP content thus seems to be related primarily to factors other than the fibre type as defined by the expression of contractile protein. These findings imply that it is not possible to generalize fibre type-dependent protein expression on the basis of biopsies from only one muscle.

Adult↗

PubMed1998

Understanding and measurement of muscle tone as related to clinical muscle pain.

Measurable sources of muscle tension include viscoelastic tone, physiological contracture (neither of which involve motor unit action potentials), voluntary contraction, and muscle spasm (which we define as involuntary muscle contraction). The latter two depend on motor unit action potentials to generate the tension. Total muscle tension is most accurately measured as stiffness. Thixotropy of muscle is an ubiquitous and functionally important phenomenon that is not commonly recognized. A clinical pain condition associated with increased muscle tension is tension-type headache, which is largely muscular in origin; it is often caused by myofascial trigger points, but not by a pain-spasm-pain cycle, which is a physiologically and clinically untenable concept. Clinical conditions associated with painful muscle spasm include spasmodic torticollis, trismus, unnecessary muscle tension, nocturnal leg cramps, and stiff-man syndrome.

Biomechanical Phenomena↗

PubMed2002

Comparison of sarcomere alterations after muscle contraction and tension loading in the rat soleus muscle.

Muscle contraction induced by 30 min of continuous nerve stimulation at 50 Hz resulted in sarcomere changes of the soleus muscle in the rat in our previous study. To further investigate the cause of sarcomere alterations, the sciatic nerve was electrically stimulated intermittently for 30 min. Nerve stimulation was also conducted after cutting the tendons of the soleus, gastrocnemius and plantaris muscles in order to prevent imposing tension on these muscles as a result to their own contractions. In addition, the muscles were pulled by weights via their tendons to load high tension for 30 min without nerve stimulation. Sarcomere alterations immediately after treatments were quantified by electron microscopy. The percentages of aberrant sarcomere areas of the soleus muscle were 25.7 +/- 16.4% (mean +/- SD) in the group of intermittent nerve stimulation with intact tendons and 21.1 +/- 35.4% in the group of tenotomy and continuous nerve stimulation, which were roughly equal to or more severe than the group of continuous nerve stimulation with intact tendons (18.8 +/- 15.8%) in our previous study. Sarcomere alterations consisted mainly of hypercontraction in these groups. Almost all sarcomere changes in the tension-loaded (pulled) soleus muscles were scarce myofilaments (1.7 +/- 1.0% by 600 g; 4.5 +/- 2.9% by 1200 g), and hypercontraction was not observed. These findings indicate that neither high tension nor a decrease of muscle blood flow during continuous contraction seems to be the primary cause of sarcomere alterations in the present study. There are probably other causes that produce aberrant sarcomeres.

Actin Cytoskeleton↗

PubMed2001

Insulin action on rates of muscle protein synthesis following eccentric, muscle-damaging contractions.

The purpose of this study was to determine whether eccentric, muscle-damaging contractions affect insulin action on muscle protein synthesis. Male Wistar rats (n = 28) were anaesthetized either once or twice separated by 7 days' rest, and one limb was electrically stimulated to contract eccentrically, while the contralateral limb served as a non-stimulated control. Twenty-four and 48 h after contractions, rates of protein synthesis were assessed in soleus and red or white gastrocnemius muscles during a hindlimb perfusion with or without insulin (20 000 microU mL(-1)). Rates of protein synthesis were not different in non-stimulated muscle, with or without insulin (P > 0.05). In red or white gastrocnemius without insulin, rates of protein synthesis were significantly reduced (P < 0.05) 24 and 48 h after a single session and 48 h after a double session of muscle contractions. However, protein synthesis was normalized with insulin 24 and 48 h after contractions in red, and 48 h after contractions in white gastrocnemius. In soleus muscle, protein synthesis was impaired only 48 h after the second session, but partially restored by insulin (P < 0.05). These results indicate that muscle becomes more sensitive to insulin action on rates of protein synthesis after muscle-damaging contractions.

Animals↗

PubMed1995

Muscle creatine kinase-deficient mice. II. Cardiac and skeletal muscles exhibit tissue-specific adaptation of the mitochondrial function.

Functional properties of in situ mitochondria and of mitochondrial creatine kinase were studied in saponin-skinned fibers taken from normal and M-creatine kinase-deficient mice. In control animals, apparent Km values of mitochondrial respiration for ADP in cardiac (ventricular) and slow-twitch (soleus) muscles (137 +/- 16 microM and 209 +/- 10 microM, respectively) were manyfold higher than that in fast-twitch (gastrocnemius) muscle (7.5 +/- 0.5 microM). Creatine substantially decreased the Km values only in cardiac and slow-twitch muscles (73 +/- 11 microM and 131 +/- 21 microM, respectively). As compared to control, in situ mitochondria in transgenic ventricular and slow-twitch muscles showed two times lower Km values for ADP, and the presence of creatine only slightly decreased the Km values. In mutant fast-twitch muscle, a decrease rather than increase in mitochondrial sensitivity to ADP occurred, but creatine still had no effect. Furthermore, in these muscles, relatively low oxidative capacity was considerably elevated. It is suggested that in the mutant mice, impairment of energy transport function in ventricular and slow-twitch muscles is compensated by a facilitation of adenine nucleotide transportation between mitochondria and cellular ATPases; in fast-twitch muscle, mainly energy buffering function is depressed, and that is overcome by an increase in energy-producing potential.

Adaptation, Physiological↗

PubMed1982

Branching of muscle spindle afferents of jaw closing muscles in the cat.

1. Functionally isolated single fibres were prepared from the cut central ends of the masseter nerve in cats. Of those firing in response to muscle stretch, most were alpha motor units but some had the properties of afferent fibres innervating muscle receptors. 2. These afferent units were remarkably sensitive to muscle stretch even under anaesthesia deep enough to eliminate all stretch evoked e.m.g. activity in masseter. Moreover, these units responded to gentle pressing of the surface of either the masseter, temporalis or pterygoid muscles. 3. On the basis of their responses to ramp stretch, to high-frequency vibration, to suxamethonium, and to gentle pressing of the muscle surface, the majority were considered to arise from primary or secondary endings of muscle spindles. 4. In reflexly induced jaw movements, the highest discharge frequency of these spindles was observed during the jaw opening phase. However, they were also activated during the jaw closing phase, indicating that the fusimotor innervation to the source spindle was still preserved. 5. From these results, it is concluded that branching of the spindle afferent outside the capsule occurs in the muscle nerve innervating cat's jaw closing muscles.

Action Potentials↗

PubMed1996

Relationship between short-range stiffness and yielding in type-identified, chemically skinned muscle fibers from the cat triceps surae muscles.

1. Transient, stretch-evoked force responses of chemically skinned muscle fibers from the cat hindlimb were investigated. The purpose of these experiments was to determine the exent to which short-range stiffness, the apparent stiffness exerted by the fiber over the first 0.5% of length change, is higher in type I than type II muscle fibers. Fibers were obtained from soleus and vastus intermedius muscles, which contain predominantly type I fibers, the LGm, a compartment of the lateral gastrocnemius muscle that contains predominantly type II fibers, and LG3, a compartment of mixed type. 2. Beyond a short range of approximately 1% of muscle length during a 0.5 muscle length/s (ML/s) stretch, most fibers exhibited an abrupt decrease in apparent stiffness or yield. Fibers from the muscles containing predominantly type S (slow twitch, or type I) fibers, soleus and vastus intermedius, exhibited such a pronounced decline in apparent stiffness that force declined as well during continued stretch. Most of the fibers from the LG3 compartment could be divided into two distinct groups depending upon whether or not they showed a force yield at the stretch velocity of 0.5 ML/s. 3. The short-range stiffness measured over the first 0.5% of stretch was greater for fibers showing force yield than for those that did not at matched initial forces and normalized stretch amplitudes. This result is consistent with the hypothesis that the same mechanism that endows the fiber with high short-range stiffness is also responsible for a greater extent of yielding. 4. Fibers from soleus were found to exhibit a force yield over a 200-fold range of velocities (0.01-2 ML/s). In contrast, most fibers from the LGm compartment showed only an increase in extent of yield with stretch velocity. Some of these fibers eventually yielded in force, but only when they were stretched at velocities > 2 ML/s. The proposed relationship between high short-range stiffness and yielding was supported by the finding that short-range stiffness increased sharply in the range of velocities where the fiber showed the greatest increase in extent of yield. 5. After the physiological experiments, fibers were subjected to SDS gel electrophoresis. Two distinct patterns of bands in the low molecular weight range were found to correspond to the two types that were identified on the basis of their dynamic mechanical properties. Fibers that did not yield at 0.5 ML/s showed a band pattern very similar to that of rabbit psoas (type II) fibers. 6. These results support the hypothesis that type I fibers are specialized in presenting a high short-range stiffness for effective postural control in advance of reflex mechanisms and that this property results from intrinsic properties of the fiber and is not due to differences in the dimensions of type I and II fibers. Yielding serves to protect the fiber from damaging levels of force during lengthening contractions. The importance of these transient properties to the mechanical behavior of muscle during ongoing movements is suggested by the observation that high stiffness followed by yielding is repeated with little alteration during successive stretches.

Animals↗

PubMed2026

Microbiota-gut-muscle axis shapes fish muscle texture by regulating collagen synthesis.

BACKGROUND: Increasing studies have emphasized the communication network between the gut microbiome and host organs, revealing that such interactions significantly influence host physiological performances. However, whether a gut-muscle axis exists to regulate muscle quality in animal production is unknown. RESULTS: In two independent cohorts, the muscle hardness of tilapia subjected to a long-term faba bean diet exhibited significant inter-individual variation. RNA-Seq analyses of the high-hardness (H) and low-hardness (L) groups pointed to collagen-based extracellular matrix as a possible factor driving muscle hardness development. Transplantation of gut microbiota from the H donor resulted in enhanced collagen synthesis in gnotobiotic zebrafish. Muscular collagen deposition was featured with an increased abundance of gut Cetobacterium. Gnotobiotic models colonized with live C. somerae exhibited enhanced collagen synthesis. Integrated analyses of microbiome function, bacterial genome, and metabolic profiles identified acetate as a key effector of C. somerae. Acetate incubation upregulated collagen I expression in TGF-β-activated fibroblasts in an acetylation-dependent manner. Mechanistically, acetate promoted the acetylation of SMAD2/3, enhancing its nuclear transport and stability, which ultimately increased collagen expression. An acetate-supplemented feeding experiment corroborated these findings. CONCLUSION: The comprehensive results provided evidences that gut microbes regulated tilapia muscle texture through SMAD2/3 acetylation-driven collagen synthesis. This study expands our understanding of the multifaceted role of the gut-muscle axis in muscle physiology. Furthermore, our findings highlight that targeting gut microbiota and the downstream collagen synthesis pathway could be promising for manipulating muscle quality in animal production. Video Abstract.

Animals↗

PubMed1996

Rippling muscles and myasthenia gravis with rippling muscles.

OBJECTIVE: To describe a patient with rippling muscles and myasthenia gravis. DESIGN: Clinical, laboratory, electrophysiologic, and muscle biopsy data are reported. SETTING: Medical office and hospital. PATIENT: We describe a patient with rippling muscles (as seen in rippling muscle disease) and myasthenia gravis (MG) with thymoma. There was no family history of rippling muscle disease in our patient. Diplopia and other symptoms of MG were initially overshadowed by the striking rippling phenomenon. The rippling resolved when the MG became florrid. INTERVENTIONS: The patient was treated with pyridostigmine, prednisone, and plasmaphereses before removal of a thymoma. MAIN OUTCOME AND RESULTS: His MG improved with treatment and the rippling has not recurred 4 months after thymectomy. CONCLUSIONS: Rippling muscle disease is rare and usually inherited. Our patient with rippling muscles (but no family history of rippling muscle disease) and MG suggests that rippling muscles may also be triggered by an autoimmune phenomenon.

Biopsy↗

PubMed2005

Axillopectoral muscle (Langer's muscle).

In a routine dissection of the axillary fossa, a muscle originating from the coracoid process of the scapula and extending to the long head of triceps brachii muscle was observed. The mentioned muscle was adhering to both the triceps brachii muscle and the tendinous part of the latissimus dorsi muscle. This anatomical variation is referred to as axillary arch (Langer's muscle or axillopectoral muscle). The muscle mass was measured 9.6 cm in length and 1.4 cm in width. The accessory muscle can be a reason of an axillary mass and can exert pressure on the neighboring neurovascular bundle or lymph routes; thus, exposing a wide range of symptoms. Therefore, variations of this area should be kept in mind in surgical interventions.

Axilla↗

PubMed1992

Selective innervation of foreign muscles following damage or removal of normal muscle targets.

The restoration of a normal pattern of neural connectivity following nerve injury depends upon the selective reinnervation of appropriate postsynaptic targets. Previous studies suggest that, in the neuromuscular system, recognition between regenerating motoneurons and target muscles depends upon the positions of origin of the motoneurons and muscles. In axolotls, portions of the motor pools of adjacent muscles overlap. We found that, following removal of a pair of adjacent hindlimb muscles, anterior and posterior iliotibialis, many regenerating iliotibialis motor axons invaded foreign muscles. A more anterior foreign muscle, puboischiofemoralis internus, received greater innervation from anterior iliotibialis motoneurons, whereas a more posterior muscle, iliofibularis, received greater innervation from posterior iliotibialis motoneurons. Furthermore, anterior iliotibialis motoneurons that reinnervated puboischiofemoralis internus occupied the rostral portion of anterior iliotibialis motor pool, which overlaps that of puboischiofemoralis internus. Anterior iliotibialis motoneurons that reinnervated iliofibularis occupied the caudal portion of the anterior iliotibialis motor pool, which overlaps that of iliofibularis. When both anterior and posterior iliotibialis were damaged so that their myofibers were permanently destroyed, the rostrocaudal origins of the motoneurons that reinnervated them were virtually the same, suggesting that the motoneurons had difficulty distinguishing between the myofiberless iliotibialis muscles. However, some iliotibialis motoneurons invaded puboischiofemoralis internus instead of their myofiberless targets. Puboischiofemoralis internus received more innervation from the anterior iliotibialis motoneurons than the positionally less appropriate posterior iliotibialis motoneurons. These data are consistent with the hypothesis that selective reinnervation of muscle depends upon a system of recognition cues based on position.

Ambystoma↗