The interaction between the synapses of a single motor fiber.

It has been shown that stimulation of synapses of the giant motor fibers of the third roots of Cambarus clarkii can block transmission at other synapses located on the same fiber. Peripherally located synapses block most synapses which are more centrally located. The reverse is true in a small number of cases. Possible reasons for this difference are discussed. It was further found that the two medial giant fibers in fresh, carefully dissected, preparations show a functional connection in the brain. It is probable that, under natural conditions, both medial giant fibers are always active at the same time.