The structure of the nervous system has been reconstructed in its entirety from photographs of serial sections taken with the electron microscope. This worm has 302 neurones, each with a predictable position and shape. The wiring diagram of the entire system is now complete. The embryological lineage of every neuron has been followed. Neural mechanisms underlying principles of behaviour Neural mechanisms underlying principles of behaviour which may be observed in any animal are being investigated with nudibranch molluscs.
Single neurons can trigger discrete behaviours.
These nerve cells are in cerebral ganglia and many of them are pigmented being the same colour among individuals and as a result can be consistently identified. By attaching electrodes it is possible to record the responses in these cells after various kinds of sensory stimuli and observe the behavioural responses. Different aspects of behaviour are organised as a hierarchy and the research focus is on how does an animal make choices eg. The neurochemical pathway is well understood. The stimuli and pathways of short term and long-term learning in this animal are thus amenable to experimentation.