Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Monkey  (2)
  • Purkinje cell  (1)
  • Single unit recording  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Phasic and tonic responses of premotor and primary motor cortex neurons to torque changes (1991)
    Springer
    Experimental brain research 86 (1991), S. 303-310 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Load compensation ; Single cell recording ; Motor areas ; Short-latency responses ; Monkey
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Responses to torque step perturbation of the wrist were compared in premotor area (PMA) and motor cortex (MI) neurons of the monkey. A substantial portion (39%) of cells recorded from the PMA had phasic responses with onset latencies as short as those found in MI (mostly between 15 and 50 ms). Responsiveness to small perturbations, directional specificity and linear correlation of phasic responses with the velocity of displacement are properties that were essentially present in the PMA. A role of somatosensory feedback to the PMA in accurate and fast up-dating of movement is suggested. Tonically sustained responses to torque change (mean latency around 60 ms) were encountered in both areas and preferentially in neurons that had a monotonic load-relationship under steady-state condition. Such cortical responses did not exhibit reflex-like features, i.e. no correlation with amplitude of torque step and resulting displacement. Instead, the new load condition seemed to be represented by the tonic response of any particular neuron in accordance with its individual firing rate-load characteristics. These tonic cortical responses may be involved in the swift and effective adaption to the actual load.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228953
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Static firing rates of premotor and primary motor cortical neurons associated with torque and joint position (1991)
    Springer
    Experimental brain research 86 (1991), S. 293-302 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Premotor area ; Motor cortex ; Torque relation ; Single unit recording ; Monkey
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Single cell activity was studied in the postarcuate premotor area (PMA) and primary motor cortex (MI) of two monkeys performing a load-bearing task with the contralateral hand. Steady-state discharge rates were examined in relation to positional maintenance of the wrist which was held in one of three given positions against graded torques directed towards flexion or extension. Significant and monotonic relationships between tonic firing rate and static torque were found in 41% of 477 MI cells and in only 26% of 470 units studied in PMA. However, for specific cell groups in the PMA the proportion of load-related neurons reached that of the MI samples; this was true for pyramidal tract neurons (PTNs) and for ‘non-PTNs’ if recorded in their vicinity. The most interesting difference pertains to the range of load over which cells in both areas modulated activity. MI neurons showed steepest change of firing rates over a limited range of small torques around zero external load; the population average displayed a sigmoidal relationship. Proportionally more PMA neurons increased their activity over the entire range of torques examined or showed the highest increase with stronger torques; the population average best fitted a quadratic function. The mean firing ratetorque slope of the PMA population was significantly smaller than that of MI. Many cells in either area were related to both torque and joint position and displayed correlates of length-tension properties of muscle. Change of position sensitivity with torque was found to parallel the rate-torque characteristics in individual neurons. Mean position sensitivity of PMA neurons increased with increasing torques in the ‘preferred’ direction. In contrast, greatest position sensitivity of the MI population occurred over the range of low torques, which means a clear quantitative dissociation from the muscular activities. The results suggest differential roles of MI and PMA in the control of ‘fine’ versus ‘gross’ muscular forces. Undoubtedly, some PMA cell elements (possibly certain output neurons) are involved in aspects of postural control of EMG adjustment to load and joint position.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228952
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Cerebellar feedback signals of a passive hand movement in the awake monkey (1984)
    Springer
    Pflügers Archiv 402 (1984), S. 292-299 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Cerebellum ; Climbing fibre ; Purkinje cell ; Awake monkey ; Passive movement ; Sensory feedback
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract From three intact and awake monkeys, 149 Purkinje cells and 44 presumed mossy fibres were recorded in the intermediate part of the cerebellar anterior lobe, and this activity was analyzed with regard to different parameters of a passive hand movement. The tonic discharge rate of the simple spikes (SS) varied according to different joint positions only in a single Purkinje cell, whereas such a position relation was found in nine out of 44 presumed mossy fibres. A phasic increase of the complex spike (CS) discharge rate of Purkinje cells in response to passive wrist movements usually occurred within 100 ms after movement onset. However, in some units a phase of increased CS rate was observed which lasted for the whole movement duration. The amount of this phasic increase in the CS rate depended on the acceleration of movement, but the SS response to movements of different velocity remained unchanged.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00585512
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...