Selective activation of functional muscle groups through stimulation of spinal motor pools

Journal ArticleA microelectrode was used to stimulate motor neurons in the lumbo-sacral spinal cord of adult cats. Consistent with spinal cord anatomical studies, we found that the motor neurons responsible for activation of individual muscle groups are situated together in specific areas of the cord, forming motor pools. Localized spinal cord stimulation of these motor pools enables selective activation of individual muscle groups. By modulating the magnitude of stimulation at different sites in the motor pools, we should be able to selectively activate different muscle groups to produce desired levels of contraction and controlled limb movements

Proposed specifications for a lumbar spinal cord electrode array for control of lower extremities in paraplegia

Journal ArticleThe goal of the study was to provide specifications for a stimulating electrode array to be implanted in the lumbosacral spinal cord as part of a functional neuromuscular stimulation (FNS) system for control of lower extremity muscles in paralyzed individuals. Dual channel stimulation of the quadriceps activation pool in the feline ventral lumbo-sacral spinal cord was performed to measure electrode interactions and to explore the effect of various stimulation paradigms on muscle fatigue. There was no measurable overlap in the populations of motor neurons activated from two different electrodes for spacings _x0015_ 1 mm with currents below 100 _x0016_A. However, a statistically significant increase in the population of activated fibers due to current summation was observed when stimuli _x0015_ 70 _x0016_A were simultaneously presented through pairs of electrodes within 3 mm of each other. Fatigue effects were studied with three paradigms: 1) stimuli were delivered through a single electrode, 2) stimuli were delivered through two electrodes with the stimulus to the second electrode presented during the refractory period of fibers stimulated by the first electrode, and 3) stimuli were interleaved between the two electrodes such that the stimulus to one electrode was presented midway between stimuli to the other electrode, and the rate of stimulation through a single electrode was half that used in the first two paradigms. Dual channel refractory and single channel stimulation did not differ from each other in the rate at which the muscle fatigued, in both cases the force decayed to 30% of its initial level within 2 min of the initiation of the stimulation regime, whereas the force with interleaved stimulation was still above the initial force at this time due to strong potentiation. Based on these results and on and activation pool dimensions obtained in an earlier study, preliminary specifications are presented for an electrode array to be implanted in the human spinal cord for functional neuromuscular stimulation

Electrical stimulation of the ventral lumbo-sacral spinal cord results in mixed recruitment order of quadriceps and tibialis anterior motor units

Journal ArticlePulse width modulated, twitch recruitment curves for quadriceps and tibialis anterior were obtained by stimulating their respective motor activation pools in the ventral lumbo-sacral portion of the spinal cord. The duration of the twitch responses were analyzed as a function of stimulus strength to determine the order of motor unit recruitment. It was found that activating the quadriceps or tibialis anterior by stimulating the spinal cord resulted in a predominantly mixed recruitment order of its motor units. These results suggest that spinal cord stimulation could have application in future neuromuscular stimulation systems where normal recruitment order of muscle fibers is desired for producing fine control of muscle activity and enhancing fatigue resistance

Muscle recruitment through electrical stimulation of the lumbo-sacral spinal cord

Journal ArticleThe goal of this study was to determine the feasibility of producing graded muscle contraction in individual muscles or muscle groups by electrically stimulating motor neurons in the lumbo-sacral spinal cord. Recruitment curves were obtained for quadriceps, tibialis anterior and triceps surae/plantaris by stimulating their activation pools in the ventral horn of the feline spinal cord. Mean twitch times-to-peak for quadriceps, tibialis anterior and triceps surae/plantaris were 33.0, 41.0, and 36.0 ms, respectively. Twitch duration as a function of stimulus strength demonstrated a mixed motor unit recruitment order, distinctively different from the inverse recruitment order exhibited by conventional methods of electrical stimulation of peripheral nerve. The recruitment curve slopes (expressed as a percentage of maximum force per nanocurrent of delivered charge) were shallow: 7.9 for quadriceps, 2.6 for tibialis anterior and 8.5 for triceps surae/plantaris. These results show that graded control of force in individual muscles or muscle groups can be obtained through spinal cord stimulation, and suggest that spinal cord stimulation could be used for functional neuromuscular stimulation applications

Selective activation of muscle groups in the feline hindlimb thorough electrical microstimulation of the ventral lumbo-sacral spinal cord

Journal ArticleSelective activation of muscle groups in the feline hindlimb by electrical stimulation of the ventral lumbo-sacral spinal cord was investigated. Spinal cord segments L5 to S1 were mapped using a penetrating tungsten needle electrode. Locations that produced isolated contraction of quadriceps, tibialis anterior or triceps surae/plantaris muscles when stimulated with a current of 40 A or less, and in which spread of activity to other muscles was not detected after increasing the stimulus to at least twice the threshold level, were defined as belonging to the target muscle's œactivation pool. The quadriceps activation pool was found to extend from the beginning of L5 to the middle of L6. The tibialis anterior activation pool extended from the beginning of L6 to the middle of L7, and the triceps surae/plantaris activation pool extended from the caudal end of L6 to the beginning of S1. The three activation pools were located in Rexed motor lamina IX and their spatial organization was found to correspond well with that of the anatomically defined motor pools innervating the same muscles. The spatial and functional segregation of motor pools manifested at the spinal cord level can have direct applications in the areas of functional electrical stimulation and motor control

Homeland Security and Wireless Telecommunications: The Continuing Evolution of Regulation

Since the grant of the first Commercial Mobile Radio Service ( CMRS ) license over twenty years ago, the wireless industry has grown from a service of convenience to one that is indispensable. What once was a device used for sporadic phone calls now is viewed by many Americans as a source of invaluable communication and security. As the wireless industry matured, government officials turned to the mobile phone as a way to make the United States safer. E-9 11, the Communications Assistance for Law Enforcement Act ( CALEA ), Wireless Priority Service ( WPS ), and Outage Reporting all were initiated on the wireless platform in the name of safety. The FCC implementation proceedings for each of these initiatives have differed markedly. In an advanced technology area such as wireless, government goals may best be achieved by relying on industry experts, because the technology is so sophisticated and constantly developing that the legislative and regulatory process at times cannot keep pace. This Article reviews wireless public safety and Homeland Security initiatives in three phases and explores the evolution of Homeland Security regulation of the wireless industry

Thematisierung als Polarisierung?

Die vorliegende Arbeit thematisiert Werbung und deren Wirkung auf die Rezipientinnen – am Fallbeispiel DOVE. Durch die Stereotypisierung und Klischeedarstellungen beeinflusst Werbung ihre Zuschauer leider auch negativ. Obwohl sie sich immer wieder als Spiegel der Gesellschaft ausweist, konfrontiert sie Konsumenten und Rezipienten mit Bildern, die fernab von Spiegel eher ein Konstrukt unrealistischer Lebensdarstellungen sind und liefert eine Reizüberflutung von beispielsweise dem, wie eine Frau zu sein hat, um glücklich zu sein und alles zu erreichen. Dies ist dabei Ursache für vermindertes Selbstbewusstsein – besonders bei jungen Frauen und führt nicht selten zu kognitiver Dissonanz. Im schwersten Falle zu krankhaftem Verhalten, um dem gängigen (nicht erreichbaren und fragwürdigen) Schönheitsideal zu enstprechen. Erst jetzt machte sich der Kosmetikkonzern DOVE die Reduktion der Verunsicherung, welche durch massenmediale Darbietungen verursacht wurde, zur Aufgabe, indem in den Kampagnen für Pflegeprodukte ausschließlich „realistische“ Frauen gezeigt werden. Im Theorieteil der Arbeit (Teil A) wird zuerst auf Massenmedien und –kommunikation (Kap. 1) eingegangen, um ein grundlegendes, mediales Verständnis zu vermitteln, während das nächste Kapitel Werbung als Thema (Kap. 2) konkreter beleuchtet, sowohl die Produzenten- als auch Rezipientenseite. Die Kapitel Schönheit und Alter (Kap. 3, 4) zeigen einen geschichtlichen Umriss, sowie den Umgang mit Schönheitsidealen und den damit einhergehenden immer lauter werdenden Wunsch nach realistischerer Darstellung. Nach dem Aufgreifen des aktuellen Gender-Themas (Kap. 5) und der vorwiegend psychologischen Erläuterung zur Personenwahrnehmung im Kap. 6, folgt im Kap. 7 mit dem modernen Corporate-Social-Responsibility-Konzept (CSR), um zu überprüfen, ob die DOVE-Kampagnen die Prämisse Nachhaltigkeit zum Ziel verfolgen. Nach einer Überleitung (Kap. 8 – DOVE) wird im Empirieteil der Arbeit (Teil B) mittels qualitativer Inhaltsanalyse nach Mayring die Wirkung einzelner DOVE-Werbekampagnen auf Rezipientinnen anhand von drei Gruppendiskussionen verschiedener Altersgruppen erforscht. Pro Diskussionsrunde wurden jeweils fünf Frauen eingeladen, um sich mit fünf ausgewählten Kampagnen auseinanderzusetzen. Die Beantwortung der Forschungsfragen, welche sich zum ersten mit der Empfindung und der (evtl. negativen) Zuschreibung des neu dargestellten Frauenbildes und zum anderen mit dem Zusammenhang zwischen Wahrnehmung und dem Selbstbild beschäftigen, standen hierbei im Fokus. Die Ergebnisse wurden dann nach Gruppen und ausgearbeiteten Kategorien für den Vergleich gegenübergestellt. Lediglich eine Forschungsfrage, die sich auf die Nachhaltigkeit im Sinne des CSR-Konzeptes bezieht, wurde bereits im letzten Kapitel des Theorieteils beantwortet. [DVD (mit Gruppendiskussionen liegt vor! Bilder zu den behandelten Kampagnen sind im Lauftext beinhaltet!)

Homeland Security and Wireless Telecommunications: The Continuing Evolution of Regulation

Since the grant of the first Commercial Mobile Radio Service ( CMRS ) license over twenty years ago, the wireless industry has grown from a service of convenience to one that is indispensable. What once was a device used for sporadic phone calls now is viewed by many Americans as a source of invaluable communication and security. As the wireless industry matured, government officials turned to the mobile phone as a way to make the United States safer. E-9 11, the Communications Assistance for Law Enforcement Act ( CALEA ), Wireless Priority Service ( WPS ), and Outage Reporting all were initiated on the wireless platform in the name of safety. The FCC implementation proceedings for each of these initiatives have differed markedly. In an advanced technology area such as wireless, government goals may best be achieved by relying on industry experts, because the technology is so sophisticated and constantly developing that the legislative and regulatory process at times cannot keep pace. This Article reviews wireless public safety and Homeland Security initiatives in three phases and explores the evolution of Homeland Security regulation of the wireless industry

Studies on the Metabolism of Glutaric Acid-3-c14 and a,Y-diaminobutyric Acid-2-c14 in Intact Rats

Biochemistr

Distribution of TT virus (TTV), TTV-like minivirus, and related viruses in humans and nonhuman primates

AbstractTT virus (TTV) and TTV-like minivirus (TLMV) are small DNA viruses with single-stranded, closed circular, antisense genomes infecting man. Despite their extreme sequence heterogeneity (>50%), a highly conserved region in the untranslated region (UTR) allows both viruses to be amplified by polymerase chain reaction (PCR). TTV/TLMV infection was detected in 88 of 100 human plasma samples; amplified sequences were differentiated into TTV and TLMV by analysis of melting profiles, showing that both viruses were similarly prevalent. PCR with UTR primers also detected frequent infection with TTV/TLMV-related viruses in a wide range of apes (chimpanzees, gorillas, orangutans, gibbons) and African monkey species (mangabeys, drills, mandrills). These findings support the hypothesis for the co-evolution of TTV-like viruses with their hosts over the period of primate speciation, potentially analogous to the evolution of primate herpesviruses