Caridoid Escape Reaction - Discovery of The First Command Neuron Mediated Behavior

Discovery of The First Command Neuron Mediated Behavior

In 1946, C.A.G. Wiersma first described the tail-flip escape in the crayfish Procambarus clarkii and noted that the giant interneurons present in the tail were responsible for the reaction. The aforementioned neuronal fibres consist of a pair of lateral giant interneurons and a pair of medial giant interneurons, and Wiersma found that stimulating just one Lateral Giant Interneuron (LG or LGI) or one Medial Giant Interneuron (MG or MGI) would result in the execution of a tail flip. Wiersma and K. Ikeda then proposed the term “Command Neuron” in their 1964 publication, and applied it to the giant interneurons ability to command the expression of the escape response. This was the first description of a command neuron mediated behavior and it indicated that the depolarization of a neuron could precipitate complex innate behaviors in some organisms.

This concept was further fleshed out with more specific and stringent conditions in 1972 when Kupfermann and Weiss published The Command Neuron Concept. The paper stated that command neurons were neurons (or small sets of neurons) carrying the entire command signal for a natural behavioral response. According to the authors, command neurons were both necessary and sufficient in the production of a behavioral response. The concept of command neuron mediated behaviors was both ground breaking and controversial, since determining command neuron mediated behaviors was a problematic process due to difficulties in understanding and interpreting anatomical and behavioral data.