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Fig. 8. Effects of the force produced by the action of individual flexor motor
neurons on the activity of sensory neurons from the lump receptor. A pulse of
depolarising current was injected into the cell body of a motor neuron to
evoke spikes. (A) Spikes in a slow flexor motor neuron innervating the
proximal muscle bundles did not elicit spikes in the lump receptor. (B)
Similarly a high frequency of spikes in another slow motor neuron innervating
distal muscle bundles did not evoke sensory spikes. A later burst of spikes in
fast flexor motor neurons, not directly related to the applied depolarisation,
caused muscle activity and sensory spikes. The bridge is unbalanced in the
intracellular recordings.