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THE DIFFERENTIATION OF TWO TYPES OF FUSIMOTOR FIBRE BY THEIR EFFECTS ON THE DYNAMIC RESPONSE OF MUSCLE SPINDLE PRIMARY ENDINGS
Author(s) -
Matthews P. B. C.
Publication year - 1962
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1962.sp001616
Subject(s) - muscle spindle , stimulus (psychology) , chemistry , stimulation , biophysics , muscle fibre , anatomy , soleus muscle , biology , neuroscience , skeletal muscle , psychology , afferent , psychotherapist
Ventral root filaments were subdivided until they contained a single γ motor fibre to the soleus muscle of the anæsthetized cat. The response of a muscle spindle primary ending to a standard stretch was observed during repetitive stimulation of such single γ fibres. All γ fibres isolated increased the discharge of the ending when the muscle was at a constant length; but some γ fibres (here called dynamic fusimotor fibres) in addition increased the sensitivity of the ending to the dynamic stimulus of stretching; in contrast, others (static fusimotor fibres) tended to decrease the dynamic sensitivity. These two different effects could be produced on the same primary ending by different γ fibres. These differences were independent of the frequency of stimulation, the amplitude of stretch and the velocity of stretching. No other consistent differences were found between the two kinds of fusimotor fibre.