Differential control of fast and slow twitch motor units in the decerebrate cat

Communications

“…Units with a low threshold for flexion were more difficult to recruit under this condition. There seems to be a close correspondence with earlier findings of Garnett & Stephens (1981) and Kanda, Burke & Walmsley (1977), who reported analogous input-dependent phenomena. From these results it can be concluded that the distribution of the input activity over the motoneurone pool differs for each task, with different weightings of the input upon different MUs.…”

Topical anesthesia: H-reflex recovery changes by desensitization of the skin

“…It has been shown in previous investigations that tonic motoneurons tend to have a faster H-reflex recovery time than phasic motoneu rons (Sabbahi Awadalla 1976;Sabbahi and Sedgwick 1979) as well as faster firing rates (Kernell 1965). Hence, it appears that some o-motoneurons are more driven by-skin inputs than are other motoneurons,a point that has been previously suggested by Burke (1973) and Kanda et al (1977). However, more studies need to be done to support this con jecture.…”

Changes in the recruitment threshold of motor units produced by cutaneous stimulation in man.

“…As the subject follows the target ramp, increasing descending drive with increasing voluntary effort brings some motoneurones to firing threshold earlier and others later than in control. Indeed in the relaxed human subject (unpublished observations) and in the decerebrate cat where descending drive is absent, cutaneous stimulation alone can cause sufficient reflex excitation to cause a muscle to contract and motor units to become active in a sequence different from that associated with a voluntary contraction in man or the tonic stretch reflex in cat (Kanda et al 1977).…”