Rapid escape reflexes in aquatic oligochaetes: variations in design and function of evolutionarily conserved giant fiber systems

This study provides neuroanatomical and electrophysiological evidence that an arrangement of three dorsal giant fibers, functioning as two distinct and dichotomous conduction pathways, has been evolutionarily conserved within the three major orders of aquatic and terrestrial oligochaetes. The authors hypothesize that differential predation pressures, together with fundamental differences in lifestyle and habitat, have led to divergence in the structure and function of evolutionarily conserved set of homologous giant interneurons.