Brain, Primitive, Flatworms
The ancestral flatworms are phyletically probably the closest animals to the progenitors of all the major lines of metazoan evolution, including vertebrate and invertebrate phyla. Because of their unique evolutionary position and the ease with which modern electrophysiological techniques can be applied to their brains, one might expect by studying them to shed light on questions about the early evolution of central nervous systems. Most modern work has been performed on several genera, in a group of marine flatworms called the acotylean polyclad platyhelminths, with Notoplana acticola receiving the greatest attention. Little significant work has been performed on the nervous systems of fresh water planarians in the last 20 years.
KeywordsReflex Pathway Membrane Time Constant Metazoan Evolution Nonspiking Interneuron Bilateral Coordination
- Keenan CL, Coss RG, Koopowitz H (1981): Cytoarchitecture of primitive brains: Golgi studies on flatworms. J Comp Neurol 195: 697716Google Scholar
- Keenan CL, Koopowitz H (1984): Ionic bases of action potentials in identified flatworm neurones. J Comp Neural 155Google Scholar
- Koopowitz H (1982): Platyhelminthes. In: Electrical Conduction and Behavior in Lower Vertebrates, Shelton G, ed. Oxford: Oxford University PressGoogle Scholar