Logo of nihpaAbout Author manuscriptsSubmit a manuscriptHHS Public Access; Author Manuscript; Accepted for publication in peer reviewed journal;
PMC full text:
J Electromyogr Kinesiol. Author manuscript; available in PMC 2013 Oct 1.
Published in final edited form as:
J Electromyogr Kinesiol. 2012 Oct; 22(5): 785–794.
Published online 2012 Feb 19. doi:  10.1016/j.jelekin.2012.01.015

Figure 3

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Cervical muscle spindle afferent response to rapid rotation of the C2 vertebra simulating the thrust phase of a high velocity, low amplitude spinal manipulation. In each panel (A, B ,C, D) top trace shows an original recording of spindle activity, middle trace shows the instantaneous discharge frequency (bin width 0.125s) and lower trace shows the C2 vertebra’s relative position. Panel A shows a decrease in the muscle spindle afferent activity during the thrust and panel B shows an increase in its frequency during displacement to the right. The bottom two panels show a muscle spindle’s response to vertebral displacement initially to the left and then right and back to the midline (C) and then with displacement initially to the right and then left and back to the midline (D). Note the DC shift (movement artefact) in the tracing of the original muscle spindle recordings (Raw Unit Activity) is greater when the vertebra is displaced contralaterally to the short dorsal rootlet being recorded. (Bolton PS and Holland CT 1998 unpublished data).