Central inputs mask multiple adult neural networks within a single embryonic network
Nature. 1999-12-01; 402(6762): 660-664
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Le Feuvre Y(1), Fénelon VS, Meyrand P.
(1)Laboratoire de Neurobiologie des Réseaux, CNRS et Université Bordeaux I, UMR 5816, Talence, France.
It is usually assumed that, after construction of basic network architecture in embryos, immature networks undergo progressive maturation to acquire their adult properties. We examine this assumption in the context of the lobster stomatogastric nervous system. In the lobster, the neuronal population that will
form this system is at first orgnanized into a single embryonic network that generates a single rhythmic pattern. The system then splits into different
functional adult networks controlled by central descending systems; these adult networks produce multiple motor programmes, distinctively different from the
single output of the embryonic network. We show here that the single embryonic network can produce multiple adult-like programmes. This occurs after the
embryonic network is silenced by removal of central inputs, then pharmacologically stimulated to restore rhythmicity. Furthermore, restoration of
the flow of descending information reversed the adult-like pattern to an embryonic pattern. This indicates that the embryonic network possesses the
ability to express adult-like network characteristics, but descending information prevents it from doing so. Functional adult networks may therefore not
necessarily be derived from progressive ontogenetic changes in networks themselves, but may result from maturation of descending systems that unmask
preexisting adult networks in an embryonic system.