Article Figures & Data
Figures
- Figure 1.
Experimental procedure for evoking homonymous H reflex and heteronymous MSR in IF and Gs muscles respectively. A, Bipolar stimulation needles inserted at the medial maleolus, adjacent to the medial plantar nerve. Bipolar recording wire electrodes are inserted into the Gs and IF muscles. B, Graphical representation of homonymous/heteronymous pathways and sciatic nerve transection for confirmation of synaptic signal. Solid lines represent monosynaptic PA pathway with collateral from IF PA to Gs motoneuron. Dashed lines represent motor efferents. C, C’, Traces showing Gs heteronymous MSR and homonymous IF H reflex before (red line) and after (black line) sciatic nerve axotomy. Notice that both late events are lost following axotomy suggesting they invole a synaptic component, whereas the early “M wave” remains. Double lines at the end of a stimulus artifact represent truncation for visual purposes.
- Figure 2.
Characterization of homonymous IF H reflex alongside heteronymous Gs MSR. A, Schematic of experimental set up. B, Example of simultaneous EMG recording from IF (left) and Gs (right) during graded stimulation of the medial plantar nerve. C–F, Recruitment characteristics of the H reflex and paired pulse interactions. G–H, Heteronymous Gs recruitment curve and paired pulse interactions.
- Figure 3.
Cortical modulation of homo/heteronymous reflexes bilaterally. A, Schematic of the experimental set up. Cortex was stimulated ipsilaterally and conditioning pulses preceded either ipsi- or contralateral medial plantar nerve stimulation by 20 ms. B, C, Percentage of animals in which Cx conditioning stimuli induced facilitation of both Gs and IF reflexes or facilitated Gs but inhibited IF. D, E, Example of animal in which Gs is facilitated and IF inhibited. D’, E’, Example of animal in which both Gs and IF reflexes are facilitated. Double lines at the end of a stimulus artifact represent truncation for visual purposes.
- Figure 4.
Modulation of bilateral homonymous and heteronymous reflexes by stimulation of the MRF. A, Schematic of the experimental set up. MRF was stimulated ipsilaterally and conditioning pulses preceded either ipsi- or contralateral medial plantar nerve stimulation by 20 ms. B, C, Percentage of animals in which MRF conditioning stimuli induced facilitation or inhibition of Gs and IF MSRs.
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