Arthur W. English

Bio: Arthur W. English is an academic researcher from Emory University. The author has contributed to research in topics: Axon & Peripheral nerve injury. The author has an hindex of 41, co-authored 127 publications receiving 5616 citations. Previous affiliations of Arthur W. English include Office of Technology Transfer.

Anatomy and innervation patterns of cat lateral gastrocnemius and plantaris muscles

Abstract: The anatomy, fiber architecture, and innervation patterns of cat lateral gastrocnemius (LG) and plantaris (P) muscles are described. The plantaris is a simple unipennate muscle arising from an aponeurosis in common with LG and inserting primarily into the tendon of m. flexor digitorum brevis, but with ligamentous connections to the calcaneus. The lateral gastrocnemius is more complex and contains three distinctly identifiable heads, each of which is a unipennate band of fibers coursing between a proximally attached aponeurosis of origin and a distal aponeurosis of insertion that gives rise to the tendocalcaneus. Following microdissection of the LG and P nerves, and using glycogen depletion of the primary muscle nerve branches, discrete motor subvolumes are demonstrated in both muscles. Despite large specific differences in fiber architecture between the LG and P muscles, their organization into compartments about primary muscle nerve branches is fundamentally similar. This principle of organization may be a basis for the observed functional and structural properties of other vertebrate muscles. It may thus constitute a unifying concept in the organization of motor control mechanisms.

A histochemical analysis of identified compartments of cat lateral gastrocnemius muscle.

Abstract: The lateral gastrocnemius muscle of cats can be divided into four discrete subvolumes or compartments which are supplied by the primary branches of its muscle nerve. The histochemical profile of each compartment was determined from the reaction for myosin ATPase after acid preincubation. Fibers were classified as fast-twitch glycolytic (FG), fast-twitch oxidative-glycolytic (FOG), or slow-twitch oxidative (SO). Each compartment in each cat examined was found to contain a relatively uniform distribution of different types of fibers. The most proximal LG compartment contains mainly type FG fibers, with relatively few type SO fibers; the most distal compartment, while still predominated by type FG fibers, contains a significantly larger proportion of type SO fibers. The histochemical profile of the intermediate compartments indicates that they contain fibers which lie intermediate in composition between these two. These results are consistent with the notion that LG compartments consist of aggregations of motor units, arranged such that muscle fibers comprising a single motor unit are contained within a single compartment.

An anatomical and functional analysis of cat biceps femoris and semitendinosus muscles

Abstract: The anatomy, architecture, and innervation patterns of the hamstring muscles, biceps femoris, and semitendinosus were examined in adult cats using microdissection and glycogen-depletion techniques. The biceps femoris muscle consists of two heads. The anterior head, which attaches mainly to the femur, is divided into two parts by the extramuscular branches of its nerve. The posterior head is innervated by a single nerve. Semitendinosus is composed of two heads, one proximal and one distal to a tendinosus inscription, each of which is separately innervated. The extramuscular branches of the nerves to these hamstring muscles thus partition them into innervation subvolumes termed parts. The available evidence suggests that each of the parts of these muscles so innervated is not equivalent to the collections of single motor units that have been described for ankle extensors as neuromuscular compartments. It is quite likely that each of the parts of the hamstring muscles may contain more than one neuromuscular compartment. Using chronically implanted EMG electrodes, the activation patterns of different parts of the hamstring muscles were analyzed during locomotion. The anterior and middle parts of biceps femoris are active during the early stance phase, probably producing hip extensor torque. The posterior part of biceps femoris and semi-tendinosus act most consistently as flexors, during the early swing phase, but also may function in synergy with hip, knee, and ankle joint extensors near the time of foot placement. Greater variability is found in the activity patterns of posterior biceps femoris and semitendinosus with respect to the kinematics of the step cycle than is observed for anterior and middle biceps femoris. It is suggested that this variation may reflect a larger role of sensory feedback in shaping the timing of activity in posterior biceps femoris and semitendinosus than in "nonarticular" muscles.

An electromyographic analysis of compartments in cat lateral gastrocnemius muscle during unrestrained locomotion

Abstract: Cat lateral gastrocnemius (LG) muscle is composed of four compartments, each of which is supplied by a primary branch of the LG muscle nerve and each of which contains a discrete population of moto...

Compartmentalization of Muscles and Their Motor Nuclei: The Partitioning Hypothesis

Abstract: This review article is designed to expose physical therapists to an examination of muscle organization and the implications that this organization has for therapeutic applications. The partitioning hypothesis is based on the fact that an individual muscle is arranged in a more complex array than simply fibers attaching at aponeuroses, tendons, or bones with a single muscle nerve innervation. Neuromuscular compartments, which are distinct subvolumes of a muscle, each innervated by an individual muscle nerve branch and each containing motor unit territories with a unique array of physiological attributes, are described. In addition, the organization of individual muscles into these subunits is paralleled by the organization of their parent motoneurons within the spinal cord. These notions are detailed in a review of data derived from studies performed primarily in cat and rat models. Recent data derived from morphological and anatomical study of human muscles support the existence of similar neuromuscular partitions. These data are complemented by physiological studies, the results from which suggest that partitions may have functional or task-oriented roles; that is, different portions of one muscle may be called into play depending on the task demands of the situation. The importance of these observations for reconsidering how we provide clinical applications, such as neuromuscular stimulation or kinesiological monitoring, is discussed.

The geometry of biological time , by A. T. Winfree. Pp 544. DM68. Corrected Second Printing 1990. ISBN 3-540-52528-9 (Springer)

Abstract: 1980 Preface * 1999 Preface * 1999 Acknowledgements * Introduction * 1 Circular Logic * 2 Phase Singularities (Screwy Results of Circular Logic) * 3 The Rules of the Ring * 4 Ring Populations * 5 Getting Off the Ring * 6 Attracting Cycles and Isochrons * 7 Measuring the Trajectories of a Circadian Clock * 8 Populations of Attractor Cycle Oscillators * 9 Excitable Kinetics and Excitable Media * 10 The Varieties of Phaseless Experience: In Which the Geometrical Orderliness of Rhythmic Organization Breaks Down in Diverse Ways * 11 The Firefly Machine 12 Energy Metabolism in Cells * 13 The Malonic Acid Reagent ('Sodium Geometrate') * 14 Electrical Rhythmicity and Excitability in Cell Membranes * 15 The Aggregation of Slime Mold Amoebae * 16 Numerical Organizing Centers * 17 Electrical Singular Filaments in the Heart Wall * 18 Pattern Formation in the Fungi * 19 Circadian Rhythms in General * 20 The Circadian Clocks of Insect Eclosion * 21 The Flower of Kalanchoe * 22 The Cell Mitotic Cycle * 23 The Female Cycle * References * Index of Names * Index of Subjects

Cellular and Molecular Regulation of Muscle Regeneration

Abstract: Charge, Sophie B. P., and Michael A. Rudnicki. Cellular and Molecular Regulation of Muscle Regeneration. Physiol Rev 84: 209–238, 2004; 10.1152/physrev.00019.2003.—Under normal circumstances, mamma...

Fiber types in mammalian skeletal muscles.

Abstract: Mammalian skeletal muscle comprises different fiber types, whose identity is first established during embryonic development by intrinsic myogenic control mechanisms and is later modulated by neural and hormonal factors. The relative proportion of the different fiber types varies strikingly between species, and in humans shows significant variability between individuals. Myosin heavy chain isoforms, whose complete inventory and expression pattern are now available, provide a useful marker for fiber types, both for the four major forms present in trunk and limb muscles and the minor forms present in head and neck muscles. However, muscle fiber diversity involves all functional muscle cell compartments, including membrane excitation, excitation-contraction coupling, contractile machinery, cytoskeleton scaffold, and energy supply systems. Variations within each compartment are limited by the need of matching fiber type properties between different compartments. Nerve activity is a major control mechanism of the fiber type profile, and multiple signaling pathways are implicated in activity-dependent changes of muscle fibers. The characterization of these pathways is raising increasing interest in clinical medicine, given the potentially beneficial effects of muscle fiber type switching in the prevention and treatment of metabolic diseases.

Development of the vertebrate neuromuscular junction.

Abstract: We describe the formation, maturation, elimination, maintenance, and regeneration of vertebrate neuromuscular junctions (NMJs), the best studied of all synapses. The NMJ forms in a series of steps that involve the exchange of signals among its three cellular components--nerve terminal, muscle fiber, and Schwann cell. Although essentially any motor axon can form NMJs with any muscle fiber, an additional set of cues biases synapse formation in favor of appropriate partners. The NMJ is functional at birth but undergoes numerous alterations postnatally. One step in maturation is the elimination of excess inputs, a competitive process in which the muscle is an intermediary. Once elimination is complete, the NMJ is maintained stably in a dynamic equilibrium that can be perturbed to initiate remodeling. NMJs regenerate following damage to nerve or muscle, but this process differs in fundamental ways from embryonic synaptogenesis. Finally, we consider the extent to which the NMJ is a suitable model for development of neuron-neuron synapses.