Ausgehend vom Prinzip der freien Energie sowie der aktiven Inferenz beschreibt dieser Beitrag die Gesamtheit der zur räumlichen und bewegungsbezogenen Eigenwahrnehmung sowie zu willkürlichen ...Bewegungen beitragenden, interagierenden Partialmechanismen als ein dynamisches komplexes funktionelles System. Dieses System befindet sich in einem fortlaufenden Prozess der Selbsterhaltung sowie -bestätigung, der zu einem dynamischen Gleichgewichtszustand führt. Ziel des umschriebenen Systems ist es, ein Modell für die Bewegungsregulation unter Führung multimodaler sensorischer Zuflüsse zu generieren, über das der Organismus in eine dynamische Wahrnehmungs-Handlungs-Interaktion mit der Umwelt tritt. Funktionsstörungen der räumlichen und bewegungsbezogenen Eigenwahrnehmung sowie der Wahrnehmung der relativen Umwelt können Funktionsstörungen des Bewegungssystem bedingen und auf Verarbeitungs- und Wahrnehmungsstörungen der Sinnessysteme beruhen. Entsprechend liefert das Prinzip der freien Energie und die einhergehende Denkweise Impulse zur Reflexion und Weiterentwicklung von bestehenden manualmedizinischen Praktiken, aber auch zur Innovation.
Proprioceptive accuracy (PAc), i.e., the acuity of perception of the state of different parts of the motor system, shows substantial intraindividual differences, and is often considered a general ...ability. However, it is questionable whether there is an association between accuracies measured with different tests at different body sites.
With the participation of 87 young individuals with regular physical activity, PAc with respect to both knee and elbow joints (joint position reproduction) and the flexors of the upper arms (weight discrimination) was measured with multiple indices. Expected and perceived performance was also assessed for each behavioral task.
Frequentist and Bayesian analysis largely supported the idea that PAc with respect to various parts of the motor system are unrelated. No dominant-subdominant differences for actual performance were found; however, PAc for the dominant and subdominant limb were associated in many cases. Finally, perceived performance was related to expected but not to actual performance for all three proprioceptive modalities.
In conclusion, actual accuracy of perception of the actual state of a part (i.e., joint, muscle) of the motor system cannot be generalized to other parts. Perceived accuracy, dominantly shaped by expectations, is independent from actual accuracy.
•Proprioceptive accuracy is the acuity of perception of the state of the motor system•Accuracies with respect to the knee, elbow, and arm flexor muscles are unrelated•Perceived accuracy is not related to actual accuracy but associated with expectation•Propioceptive accuracy is not a generalizable characteristic
The Role of PIEZO2 in Human Mechanosensation Chesler, Alexander T; Szczot, Marcin; Bharucha-Goebel, Diana ...
The New England journal of medicine,
10/2016, Letnik:
375, Številka:
14
Journal Article
Recenzirano
Odprti dostop
Inactivating variants in
PIEZO2,
which encodes a stretch-gated ion channel, impair touch perception and proprioception. Visual cues partially compensate for these impairments, allowing affected ...persons to perform complex movements with greater accuracy.
The ability to sense force, which is known as mechanosensation, provides humans and other animals with important information about the environment; it is crucial for social interactions, such as comforting or caressing, and is required for motor coordination. A number of anatomical classes of somatosensory neurons with distinct selectivity for mechanical stimuli have been identified, but the way in which these inputs combine to provide the richness of the human sense of touch remains unclear.
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Similarly, proprioception is considered to be essential for posture and controlled movement, but little is known about the underlying mechanisms and the precise role . . .
La mécanotransduction représente la conversion d’un stimulus mécanique en signal électrique et/ou biochimique au niveau cellulaire. Ce phénomène revêt une importance fondamentale dans de nombreux ...processus aussi divers que la prolifération, la différenciation, la migration et l’apoptose, et dans les fonctions sensorielles, incluant le sens du toucher, la proprioception et la nociception. La transformation du stimulus physique repose sur la présence de canaux ioniques dits mécanosensibles, localisés au niveau du champ récepteur. L’identification des canaux ioniques de type PIEZO et la caractérisation de leurs fonctions dans le toucher et la proprioception constituent des avancées majeures dans notre compréhension des processus moléculaires de la mécanotransduction. Pour autant, de nombreux acteurs moléculaires restent à identifier, en particulier ceux impliqués dans la mécanonociception et la douleur mécanique. Cette revue a pour but de décrire le rôle des canaux PIEZOs dans les fonctions somatosensorielles et discute les dernières avancées portant sur l’identification de nouveaux acteurs moléculaires chez les mammifères. Une meilleure connaissance de ces acteurs moléculaires permettra de développer de nouvelles stratégies thérapeutiques dans plusieurs domaines cliniques.
PIEZO2 is the essential transduction channel for touch discrimination, vibration, and proprioception. Mice and humans lacking Piezo2 experience severe mechanosensory and proprioceptive deficits and ...fail to develop tactile allodynia. Bradykinin, a proalgesic agent released during inflammation, potentiates PIEZO2 activity. Molecules that decrease PIEZO2 function could reduce heightened touch responses during inflammation. Here, we find that the dietary fatty acid margaric acid (MA) decreases PIEZO2 function in a dose-dependent manner. Chimera analyses demonstrate that the PIEZO2 beam is a key region tuning MA-mediated channel inhibition. MA reduces neuronal action potential firing elicited by mechanical stimuli in mice and rat neurons and counteracts PIEZO2 sensitization by bradykinin. Finally, we demonstrate that this saturated fatty acid decreases PIEZO2 currents in touch neurons derived from human induced pluripotent stem cells. Our findings report on a natural product that inhibits PIEZO2 function and counteracts neuronal mechanical sensitization and reveal a key region for channel inhibition.
Scapholunate ligaments (SLLs) play a well-established role in maintaining carpal alignment and kinematics, and are innervated with sensory mechanoreceptors located within the ligaments. They are ...involved in the afferent arc of dynamic wrist stability. The aim of this study was to describe the changes in these mechanoreceptor populations in injured SLLs.
Injured SLLs were collected from human wrists at the time of SLL reconstruction or limited wrist fusion, where the ligament remnants would otherwise be discarded. These specimens were formalin-fixed and paraffin-embedded for immunohistochemical analysis to identify mechanoreceptors, which were then classified by type and location within the ligament.
A total of 15 ligaments were collected, with the interval from injury ranging from 39 days-20 years. Eleven ligaments were collected less than one year after injury, and four ligaments were collected two years or more after injury. A total of 66 mechanoreceptors were identified, with 50 mechanoreceptors identified in nine of the 11 specimens collected less than one year after injury. In this group, 54% of the mechanoreceptors resided in the volar subunit, 20% in the dorsal subunit, and 26% in the proximal subunit. Two of the four specimens collected two years or later after injury contained mechanoreceptors, all of which were located in the dorsal subunit. Increasing time from injury demonstrated a decline in mechanoreceptor numbers within the volar subunit.
Mechanoreceptors were consistently located in the SLL, particularly in the volar subunit of specimens collected less than one year after injury.
Ligament reconstruction techniques aim to primarily reconstitute the biomechanical function of the disrupted SLL; however, re-establishing the afferent proprioceptive capacity of the SLL may be a secondary objective. This suggests the need to consider the reconstruction of its volar subunit particularly in those managed within one year of injury.
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