Some remarks on alleged qualitative differences between anamniote and amniote nervous systems

There are no 'lower' compared to 'higher' vertebrates (craniates) placed along a linear process of evolution. The different vertebrate/craniate groups evolved independently from a common ancestor, and during this evolution, increases in the complexity of nervous systems and of behaviour are as common as simplification (e.g., in myxinoids, lungfishes and amphibians). The organization of premotor networks is basically the same among tetrapods. Similar to the afferent sensory systems (e.g., the visual system), the premotor system--at least in the context of feeding and calling--is organized in a parallel fashion, with separate channels carrying different information to motor centres, which are the level of integration. A command neuron or command neuron ensemble system exists neither in anamniotes nor in amniotes. At feeding or calling, anamniotes exhibit no stereotyped behaviour or 'fixed action pattern' compared to the plastic behaviour of amniotes; differences are only quantitative. All vertebrates possess bulbar and spinal motor program modules, which can be controlled in a flexible way by descending pathways and reafferent circuits.