Synaptic Activity in Motoneurons during Natural Stimulation of Muscle Spindles

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Science  04 Mar 1966:
Vol. 151, Issue 3714, pp. 1088-1091
DOI: 10.1126/science.151.3714.1088


Synaptic activity evoked in cat motoneurons during stretch stimulation of muscle spindles in the homonymous muscle has been studied by intracellular recording. A class of miniature excitatory postsynaptic potentials evoked by such physiologic stimulation results from activity in single group la spindle afferent fibers, and the criterion for identification is a predictable pattern of rhythmic occurrence of the synaptic potentials. Statistical examination of the amplitude distributions of this class of miniature synaptic potentials suggests that some group Ia fibers liberate a relatively large number of quantal excitatory postsynaptic potential units per fiber impulse.