02210nas a2200205   4500008004100000022001400041245007200055210006900127260001200196300001600208490000700224520163400231653001101865653001201876100002101888700001301909700001301922700002101935856004801956       2006                        eng d  a0022-307700aOperant conditioning of reciprocal inhibition in rat soleus muscle.0 aOperant conditioning of reciprocal inhibition in rat soleus musc  c10/2006  a2144–21500 v963 aOperant conditioning of the H-reflex, the electrical analog of the spinal stretch reflex (SSR), induces activity-dependent plasticity in the spinal cord and might be used to improve locomotion after spinal cord injury. To further assess the potential clinical significance of spinal reflex conditioning, this study asks whether another well-defined spinal reflex pathway, the disynaptic pathway underlying reciprocal inhibition (RI), can also be operantly conditioned. Sprague-Dawley rats were implanted with electromyographic (EMG) electrodes in right soleus (SOL) and tibialis anterior (TA) muscles and a stimulating cuff on the common peroneal (CP) nerve. When background EMG in both muscles remained in defined ranges, CP stimulation elicited the TA H-reflex and SOL RI. After collection of control data for 20 days, each rat was exposed for 50 days to up-conditioning (RIup mode) or down-conditioning (RIdown mode) in which food reward occurred if SOL RI evoked by CP stimulation was more (RIup mode) or less (RIdown mode) than a criterion. TA and SOL background EMG and TA M response remained stable. In every rat, RI conditioning was successful (i.e., change > or =20% in the correct direction). In the RIup rats, final SOL RI averaged 171+/- 28% (mean +/- SE) of control, and final TA H-reflex averaged 114 +/- 14%. In the RIdown rats, final SOL RI averaged 37 +/- 13% of control, and final TA H-reflex averaged 60 +/- 18%. Final SOL RI and TA H-reflex sizes were significantly correlated. Thus like the SSR and the H-reflex, RI can be operantly conditioned; and conditioning one reflex can affect another reflex as well.10aReflex10aStretch1 aChen, Xiang Yang1 aChen, Lu1 aChen, Yi1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/16807351