The Intersegmental Coordinating System of the Lamprey: Experimental and Theoretical Studies

There is considerable evidence that the locomotor CPGs of vertebrates are organized as groups of unit burst generators, or neural oscillators (cf. Grillner, 1981), Each oscillator controls a single muscle or functional muscle group. The oscillators are coupled together by coordinating systems in a flexible manner to produce the full range of required locomotor movements. In all vertebrates tested to date coordinating networks are intrinsic to the spinal cord. There may be more or less susceptibility to external control, but all have at least some “default” coordination pattern which is guaranteed by spinal intersegmental coupling (cf. Cohen, to appear, B, for Review). Unfortunately, little is known regarding the details of the structure or organization of either the oscillators or the coordinating systems in any vertebrates other than the lamprey.