Fig. 2

Reflex actions exerted on abdominal motoneurons by stimulating afferent fibers. a Antidromic spike evoked by stimulating the medial branch (upper trace) and after-hyperpolarization (lower trace). b Ia-EPSPs evoked by stimulating the medial branch below the threshold (upper trace) and cord dorsum potential (lower trace). The broken line indicates the extracellular recording from the impaled motoneuron. c Relationship of the amplitude of the action potential recorded at the root entry zone to the stimulus intensity (upper trace), and of the Ia-EPSP amplitude to stimulus intensity (lower trace). The abscissa indicates the stimulus intensities relative to the threshold of action potentials recorded at the root entry zone. The ordinate indicates the amplitude. d Antidromic spike evoked by stimulating the lateral branch (upper trace) and after-hyperpolarization (lower trace). e Ia-EPSPs evoked by stimulating the medial branch below the threshold (upper trace) and action potentials recorded at the root entry zone (lower trace). The broken line indicates the extracellular recording from the impaled motoneuron. f Relationship of the amplitude of the action potential recorded at the root entry zone to the stimulus intensity (upper trace), and of the Ia-EPSP amplitude to the stimulus intensity (lower trace). The abscissa indicates the stimulus intensities relative to the threshold of action potentials recorded at root entry zone. The ordinate indicates the amplitude. Ia-EPSP excitatory postsynaptic potential of Ia fibers; R-IPSP recurrent inhibitory postsynaptic potential