A. Kreischer et al., MUSCLE COORDINATION IN HINDLIMBS OF MICE AFTER BILATERAL NERVE REGENERATION, Restorative neurology and neuroscience, 5(3), 1993, pp. 191-196
The common peroneal nerve was transected bilaterally in 25 adult mice.
Nerve stumps were immediately readapted without nerve suture. Before
transection and after nerve regeneration the muscle coordination of ti
bialis anterior (TA) and medial gastrocnemius (MG) muscle was examined
by electromyographic recordings from both muscles (EMG) during free r
unning. Using a personal computer, the degree of muscle coordination b
etween TA and MG was determined by calculating a coordination index. I
n normal mice an antagonistic innervation pattern was observed. After
nerve transection and regeneration the degree of muscle coordination o
f TA and MG substantially decreased with great interindividual but als
o great intraindividual variation. In 16 mice there was no correlation
between the coordination index of the left and right hindlimbs. In ni
ne out of 25 mice reinnervation was absent on one side. These results
suggest that nerve regeneration by axonal sprouting to appropriate or
foreign muscles occurs at random and that there are no intraindividual
factors which might promote the finding of the proper target muscle.