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Motorische Systeme
Abstract
Wer die zielsicheren, eleganten Bewegungen einer springenden Katze oder die Fingerfertigkeit eines Klaviervirtuosen beobachtet,
dem erscheint es wenig aussichtsreich, diese motorischen Glanzleistungen in einzelne neuronale Mechanismen aufzulösen. Erfolgreicher
erscheint der pathophysiologische Ansatz, aus Läsionen, die mit der bildgebenden Diagnostik lokalisiert werden können, und
den resultierenden motorischen Störungen Rückschlüsse auf die normale Funktion dieser Strukturen zu ziehen. Wenn auch elektrophysiologische
und modernste funktionelle Bildgebung gestatten, motorische und insbesondere kognitive Prozesse beim Gesunden zu untersuchen,
resultiert das Verständnis der Funktion einzelner Komponenten der Motorik und deren Zusammenspiel doch überwiegend aus der
Pathophysiologie.
... In our study, participants might not have considered the standing task to be challenging or dangerous for losing balance control, even when balance performance decreased under DT conditions. Standing upright presents a relatively simple task that is, evolutionarily speaking, controlled by older cerebellum parts and brainstem motor cells without necessarily involving higher structures of the CNS (Lehmann-Horn, 2011). Yet standing still does require minimal attention resources (Lacour et al., 2008). ...
Effects of a Visual-Verbal Stroop-Test on Balance Performance of Older Adults
Wollesen, Bettina1; Voelcker-Rehage, Claudia2; Regenbrecht, Tobias1; Mattes, Klaus 1
1University of Hamburg, Department of Human Movement Science,
Mollerstraße 2, 20148 Hamburg, Germany
e-mail: bettina.wollesen@uni-hamburg.de (corresponding author); tobias.regenbrecht@uni-hamburg.de; klaus.mattes@uni-hamburg.de
2 Chemnitz University of Technology, Department of Human- and Social Science, Chemnitz, Germany
Thüringer Weg 11, 09126 Chemnitz, Germany
e-mail: claudia.voelcker-rehage@hsw.tu-chemnitz.de
Introduction
More than 30% of people over 65 fall at least once per year, mostly as a result of instability (Granacher, 2010). The examination of fall risk while standing and walking is important to identify the interplay between internal factors of postural control and to develop appropriate training programs. The dual task (DT) paradigm is used to investigate balance decrements. However, there are inconsistent findings whether performance decreases or increases in DT situations (Holtzer, Wang & Verghese, 2014). Following different theories (e.g. limited resource hypothesis; cross domain competition model), these findings can be explained by task settings and task complexity. This study explores, which theoretical model is suitable to explain changes in balance performance for a visual verbal Stroop task.
Methods
DT performance of 28 participants (> 65 years) in a Stroop test was compared while standing (sway velocity (v), Kistler; Winterthur Germany, 100HZ) and walking (step length, step width (SW), peak forces of heel, mid- and forefoot, h/p/cosmos treadmill Zebris; Isny, Germany: FDM-T, 100HZ). Ony way ANONA statistics were evaluated using SPSS 22 (IBM statistics Armonk, NY).
Results
SW and v increased from ST to DT conditions and step length decreased [left: F(1,27) = 13.09, p = .001, ηp ² = .326; right: F(1,27) = 12.36, p = .002, ηp² = .314]. Peak forces of the forefoot were reduced [left: F(1,27) = 9.82, p = .004, ηp² = .267; right: F(1,27) = 10.38, p = .003, ηp² = .278] whereas forces of the midfoot increased [left: F(1,27) = 4.19, p = .051, ηp² = .134; right: F(1,27) = 4.31, p = .048, ηp² = .138]. Correct answers of the Stroop test decreased from the baseline condition to DT walking [F(1,27) = 5.59, p = .025, ηp² = .025].
Discussion
For both conditions (standing and walking), the limited resources hypothesis fits best. Moreover, not all modified gait variables could be defined as negative DT costs. Increased SW and decreased step length might be used to compensate influences on lateral stability while demands on motor-cognitive resources increase. Further, drawing conclusions from a standing task on walking conditions might lead to misinterpretations.
References
Granacher, U., Bridenbaugh, S.A., Muehlbauer, T., Wehrle, A. & Kressig, R.W. (2010). Age-related effects on postural control under multi-task conditions. Gerontology, 57, 247-255.
Holtzer, R., Wang, C. & Verghese, J. (2014). Performance variance on walking while talking tasks: theory, findings, and clinical implications. Age, 36, 373-381.
... [%]). controlled by older cerebellum parts and brainstem motor cells without necessarily involving higher structures of the CNS ( Lehmann-Horn, 2011). Yet standing still does require minimal attention resources ( Lacour et al., 2008). ...
The dual task (DT) paradigm has been used to investigate decrements in balance performance while walking and standing in fall prevention studies with older adults. However, there are inconsistent findings whether balance performance decreases or increases in DTsituations. Following different theoretical models (e.g. limited resource hypothesis or cross domain competition model), these inconsistent findings can be explained by task settings and task complexity. We compared DT performance in an executive control task (Stroop test) while standing and walking to analyze which theoretical model would fit our data best. Twenty-eight persons (> 65 years) were examined under single task (ST) and DT conditions for standing (sway length and sway velocity) and walking (step length, step width, peak forces of the heel, mid- and forefoot).
The aim of the present study was to explore the effect of caffeine consumption (CC) on cognitive motor interference while walking and maintaining balance in middle-aged women.
Twenty middle-aged women (52 ± 2.0 years; height 158 ± 2.0 cm; body mass 77 ± 14.9 kg; body mass index ±3.4 kg/m2, mean ± SD) participated in this study. Participants completed measures of a single task (ST) cognitive, a ST motor and a dual task (DT) cognitive-motor tests before and after either caffeine (100 mg) or placebo ingestion. Results showed that before CC, both motor (P < 0.0005) and cognitive (P < 0.05) performances decreased in the DT condition compared to the ST one. After CC, no significant difference in the motor performances between ST and DT conditions was observed. In fact, both standing and walking DT performances were improved as indicated by a significant (P < 0.05) decrease in the dual task cost (DTC) of motor performances. In conclusion, middle-aged women showed difficulties to manage DT situations in which a cognitive and a motor task must be performed concurrently. Caffeine is an effective ergogenic aid to improve both cognitive and motor performances during DT conditions and could be an alternative to nullify the deteriorating effect of DT when maintaining balance and walking in middle-aged women. These enhancements could offer great potential for everyday functioning.
Diese Arbeit befasst sich mit dem Zusammenhang des Fasziensystems – dem dreidimensionalen Netzwerk im menschlichen Körper – und der Propriozeption – der Wahrnehmung der Lage des Körpers im dreidimensionalen Raum – aus trainingswissenschaftlicher Sicht. Es wird ergründet, was Propriozeption ist, welchen Einfluss sie auf die sportliche Leistungsfähigkeit hat und inwiefern sie durch Training verbessert werden kann. Im Anschluss daran wird darauf eingegangen, worum es sich beim Fasziensystem handelt, welche Bedeutung es für die Propriozeption hat und welche Möglichkeiten es gibt, fasziale Strukturen zu trainieren. Abschließend soll geklärt werden, welche Schlussfolgerungen sich hieraus für das Training der propriozeptiven Fähigkeiten ergeben.
Bei der Propriozeption handelt es sich um bewusste wie unbewusste
Wahrnehmungsresultate, die die Körperposition- und -bewegung im Raum betreffen. Im engen Sinn bezieht sie sich auf die Informationen aus Rezeptoren in der Körperperipherie. Im weiten Sinn beruht sie auf der Integration des multimodalen Inputs aus verschiedenen Sinnessystemen und supraspinalen Instanzen. Begriffe, die sich auf die sinnesphysiologischen Grundlagen beziehen, sind vom Begriff
„Propriozeption“ abzugrenzen. So umfasst der Begriff „propriozeptives System“ die Kette physikochemischer Ereignisse, die an der Aufnahme und Weiterleitung von sensorischen Informationen aus der Körperperipherie über Bewegung und Position
beteiligt sind.
Die Propriozeption ist gelenkspezifisch und dient der Bewegungskontrolle.
Insbesondere die propriozeptive Wahrnehmung des Sprunggelenks ist von
Bedeutung für die sportliche Leistungsfähigkeit. Die propriozeptiven
Wahrnehmungsfähigkeiten können durch Training verbessert werden. Die genauen
zentralen wie peripheren Anpassungsmechanismen sind indes nicht endgültig
geklärt und auch hinsichtlich des optimalen Trainingsumfangs besteht noch weiterer
Forschungsbedarf.
Eine Vielzahl von Rezeptoren, die propriozeptive Informationen liefern, befinden sich
im Fasziensystem. Dieses lässt sich in Schichten einteilen und vor allem die tiefe
Faszie, die die aponeurotische wie die epimysiale Faszie umfasst, ist von Relevanz
für die propriozeptive Wahrnehmung. Die mechanische Beschaffenheit des faszialen
Gewebes trägt maßgeblich dazu bei, inwiefern Propriozeptoren aktiviert werden.
Erste Studien konnten zeigen, dass eine myofasziale Selbstmassage der
Oberschenkelrückseite zu akuten, aber auch überdauernden Verbesserungen der
Wahrnehmung des Hüft- und Kniewinkels führt. Dabei zeigte die Anwendung mit
vibrierenden Hartschaumrollen gegenüber der Anwendung mit nicht vibrierenden
signifikant bessere Ergebnisse.
Es deutet daraufhin, dass durch Training, das auf eine Verbesserung der
mechanischen Eigenschaften des faszialen Bindegewebes abzielt, auch die
propriozeptive Wahrnehmung verbessert werden kann. Da hinsichtlich der Anpassungsmechanismen und des optimalen Trainingsumfangs noch keine Klarheit besteht, sollte zukünftige Forschung prüfen, ob grundsätzlich ein Zusammenhang zwischen der faszialen Gewebeelastizität und propriozeptiven Wahrnehmungsleistungen festzustellen ist. Weiterhin besteht Forschungspotenzial hinsichtlich der Auswirkungen spezifischer Interventionen auf propriozeptive Sinnesmodalitäten an unterschiedlichen Gelenken.
The aim of the thesis was to compare age-specific adaptations by stretch training. A systematic review was first carried out, followed by a meta-analytical examination. In addition, for the first time in older people, biomechanical and neurophysiological characteristics of the musculature were empirically investigated after a long-term training intervention and compared with a younger age group.
With the systematic review and the following meta-analytical examination, adaptations due to stretching in younger and older adults were investigated on the basis of 42 primary studies. The dependent variable is usually defined one-dimensionally by achieving maximum range of motion (ROM). Both younger and older adults achieved great effect-sizes in terms of maximum ROM after stretching. It seems that older adults need longer periods of training and tend to benefit from self-stretching and sub-maximum stretching intensity. Furthermore, in older adults with passive static stretching, the stretching duration should be longer than 30 seconds. Few studies investigated the adaptation phenomena in a multidimensional manner in the sense of additional biomechanical parameters such as maximum passive-torque, stiffness or passive elastic energy. Only one study examined the maximum passive torque in older adults compared to younger adults. Since this one study carried out a passive-static stretching training with older adults, the effect-sizes of the studies were compared with younger adults who also carried out passive-static stretch training. Older people show a medium effect-size and younger ones a small effect-size. Due to age-related differences in effect-sizes, older people seem to respond better to passive-static stretching than younger people. In the context of the empirical investigation, it could be shown in summary that age has a negative effect on the maximum ROM, the maximum passive torque, the passive-elastic stiffness and the passive-elastic energy of the ischiocrural musculature. The adaptations caused by ten-week stretch training were similar to maximum ROM in both age groups. In addition, the younger adults did not show significantly larger percentage changes compared to the older adults in terms of maximum passive torque and passive elastic energy. It can be assumed that older people benefit as much from regular stretching as younger people. Age-specific tests were conducted to determine whether the EMG onset influences maximum ROM. The absolute EMG onset was similar for both age groups and remained almost unchanged over the intervention period. The relative EMG onset did not decrease significantly in both age groups and occurred at a later time for pre- and post-test in the old age group. Since the relative EMG-Onset is dependent on maximum ROM and the young age group achieved higher ROM at all times of measurement, this results in an earlier relative EMG-Onset of the young age group. The improvement of the maximum ROM after a long-term stretching workout can be attributed to an adjustment of the subjective pain perception in both older and younger adults according to the results of the empirical investigation. It could not be determined that muscle elasticity in the form of stiffness had a significant influence on the improvement of ROM. Furthermore, it could not be determined that a neurophysiological reflex response of the musculature during muscle stretching influences the change of the maximum ROM by a long-term stretch training.
Ca(2+) regulation of contraction in vertebrate striated muscle is exerted primarily through effects on the thin filament, which regulate strong cross-bridge binding to actin. Structural and biochemical studies suggest that the position of tropomyosin (Tm) and troponin (Tn) on the thin filament determines the interaction of myosin with the binding sites on actin. These binding sites can be characterized as blocked (unable to bind to cross bridges), closed (able to weakly bind cross bridges), or open (able to bind cross bridges so that they subsequently isomerize to become strongly bound and release ATP hydrolysis products). Flexibility of the Tm may allow variability in actin (A) affinity for myosin along the thin filament other than through a single 7 actin:1 tropomyosin:1 troponin (A(7)TmTn) regulatory unit. Tm position on the actin filament is regulated by the occupancy of NH-terminal Ca(2+) binding sites on TnC, conformational changes resulting from Ca(2+) binding, and changes in the interactions among Tn, Tm, and actin and as well as by strong S1 binding to actin. Ca(2+) binding to TnC enhances TnC-TnI interaction, weakens TnI attachment to its binding sites on 1-2 actins of the regulatory unit, increases Tm movement over the actin surface, and exposes myosin-binding sites on actin previously blocked by Tm. Adjacent Tm are coupled in their overlap regions where Tm movement is also controlled by interactions with TnT. TnT also interacts with TnC-TnI in a Ca(2+)-dependent manner. All these interactions may vary with the different protein isoforms. The movement of Tm over the actin surface increases the "open" probability of myosin binding sites on actins so that some are in the open configuration available for myosin binding and cross-bridge isomerization to strong binding, force-producing states. In skeletal muscle, strong binding of cycling cross bridges promotes additional Tm movement. This movement effectively stabilizes Tm in the open position and allows cooperative activation of additional actins in that and possibly neighboring A(7)TmTn regulatory units. The structural and biochemical findings support the physiological observations of steady-state and transient mechanical behavior. Physiological studies suggest the following. 1) Ca(2+) binding to Tn/Tm exposes sites on actin to which myosin can bind. 2) Ca(2+) regulates the strong binding of M.ADP.P(i) to actin, which precedes the production of force (and/or shortening) and release of hydrolysis products. 3) The initial rate of force development depends mostly on the extent of Ca(2+) activation of the thin filament and myosin kinetic properties but depends little on the initial force level. 4) A small number of strongly attached cross bridges within an A(7)TmTn regulatory unit can activate the actins in one unit and perhaps those in neighboring units. This results in additional myosin binding and isomerization to strongly bound states and force production. 5) The rates of the product release steps per se (as indicated by the unloaded shortening velocity) early in shortening are largely independent of the extent of thin filament activation ([Ca(2+)]) beyond a given baseline level. However, with a greater extent of shortening, the rates depend on the activation level. 6) The cooperativity between neighboring regulatory units contributes to the activation by strong cross bridges of steady-state force but does not affect the rate of force development. 7) Strongly attached, cycling cross bridges can delay relaxation in skeletal muscle in a cooperative manner. 8) Strongly attached and cycling cross bridges can enhance Ca(2+) binding to cardiac TnC, but influence skeletal TnC to a lesser extent. 9) Different Tn subunit isoforms can modulate the cross-bridge detachment rate as shown by studies with mutant regulatory proteins in myotubes and in in vitro motility assays. (ABSTRACT TRUNCATED)
Over the past two decades, deep brain stimulation (DBS) has supplanted lesioning techniques for the treatment of movement disorders, and has been shown to be safe and efficacious. The primary therapeutic indications for DBS are essential tremor, dystonia and Parkinson's disease. In the case of Parkinson's disease, DBS is effective for treating the primary symptoms--tremor, bradykinesia and rigidity--as well as the motor complications of drug treatment. Progress has been made in understanding the effects of stimulation at the neuronal level, and this knowledge should eventually improve the effectiveness of this therapy. Preliminary studies also indicate that DBS might be used to treat Tourette's syndrome, obsessive-compulsive disorder, depression and epilepsy. As we will discuss in this review, the success of DBS depends on an appropriate rationale for the procedure, and on collaborations between neurologists and neurosurgeons in defining outcomes.
Im Griechischen heißt „bios“ das Leben und„logos“ das Wort oder die Kunde. Biologie ist also die Kunde vom Leben oder die Lehre von der belebten Natur und den Gesetzmäßigkeiten im Lebensablauf der Pflanzen, Tiere und Menschen. Bei der Untersuchung von Aufbau und Funktion der Lebewesen benutzt die Biologie die gleichen Denkansätze, mit denen Physik und Chemie die unbelebte Natur studieren. Die Biologie des Menschen konzentriert sich auf ein einziges Lebewesen, nämlich uns selbst. Die verschiedenen Teildisziplinen der modernen Humanbiologie sind alle früher oder später aus dem ältesten großen humanbiologischen Fach hervorgegangen, nämlich der Anatomie. Eine ihrer ersten Töchter war die in diesem Buch besonders wichtige Physiologie. Diese ist die Kunde vom Körper (physis = Körper, logos = Wort, Kunde, s. o.), genauer die Lehre von den normalen Lebensfunktionen.
The monosynaptic stretch reflex is a fundamental feature of sensory-motor organization in most animal groups. In isolation, it serves largely as a negative feedback devoted to postural controls; however, when it is involved in diverse movements, it can be modified by central command circuits. In order to understand the implications of such modifications, a model system has been chosen that has been studied at many different levels: the crayfish walking system. Recent studies have revealed several levels of control and modulation (for example, at the levels of the sensory afferent and the output synapse from the sensory afferent, and via changes in the membrane properties of the postsynaptic neuron) that operate complex and highly adaptive sensory-motor processing. During a given motor task, such mechanisms reshape the sensory message completely, such that the stretch reflex becomes a part of the central motor command.
The nervous system contains a toolbox of motor programs in the brainstem and spinal cord--that is, neuronal networks designed to handle the basic motor repertoire required for survival, including locomotion, posture, eye movements, breathing, chewing, swallowing and expression of emotions. The neural mechanisms responsible for selecting which motor program should be recruited at a given instant are the focus of this review. Motor programs are kept under tonic inhibition by GABAergic pallidal neurons (the output nuclei of the basal ganglia). The motor programs can be relieved from pallidal inhibition through activation of striatal neurons at the input stage of the basal ganglia. It is argued that the striatum has a prominent role in selecting which motor program should be called into action.
Biologische Psychologie, 6. Aufl
- N Birbaumer
- R F Schmidt
- N. Birbaumer
The cognitive neuroscience of action
- M Jaennerod
- M. Jaennerod