Commentary/Selverston: Central pattern generators

and ion channels must be functionally described in order to obtain a full understanding of a CPG, we will not have a detailed, mechanistic explanation for some considerable length of time. A complete compilation of the detailed molecular biophysics of neurons will long remain the "quark" of cellular and integrative neurobiology. The most disturbing feature of the Selverston paper is its pessimistic tone and its final leap into nihilism. Science has been marked by the episodic appearance of nihilists. Often these negative spirits have had a positive influence upon empiricism by raising doubts regarding the state of knowledge at the time, and the empiricists would respond with better experiments, more rigorous controls, and more conclusive results. Neurobiology has probably had more nihilism than most other sciences simply because of its subject the nervous system and its long-term goal, an understanding of brain function. As early as 1933, Niels Bohr raised the fundamental philosophical question of whether any brain was capable of understanding those connections which were responsible for its functioning, including its ability to understand. Gunther Stent (1969) examined a series of historic trends in both the arts and the sciences and predicted an end to progress as we know it (implying, of course, an end to the systematic investigation of neurobiological problems). Jerome Lettvin has repeatedly argued in public forum that the nervous system is so complicatedly and redundantly wired that no amount of experimentation will produce an understanding of its functions, and we should, therefore, simply not try. I will refrain from the temptation of waving the banner of neurobiology by listing some of the (ever-increasing) examples of progress. Putting philosophical and theoretical considerations aside, it is patently clear that we can, and have, learned a great deal about the nervous system in general and about CPGs in particular. While there may well be some limit as to what we can understand about the functions of the nervous system set by "uncertainty principles" or by "social evolution," it is nevertheless especially distressing when an experimentalist such as Selverston embraces nihilism. One can but wonder what motivated Selverston to write the target article: either he is playing devil's advocate and attempting to evoke some patriotic response from the neurobiological community, or he believes what he has written. If the former is true, the article is unnecessary; if the latter is true, one wonders why he persists in his chosen (futile) research activities trying to understand the workings of a central pattern generator in the lobster stomach.