Frontiers in Computational Neuroscience (May 2013)
Evolutionary and developmental modules
Abstract
The identification of biological modules at the systems level often follows top‐down decomposition of atask goal, or bottom‐up decomposition of multidimensional data arrays into basic elements or patternsrepresenting shared features. These approaches traditionally have been applied to mature, fullydeveloped systems. Here we review some results from two other perspectives on modularity, namelythe developmental and evolutionary perspective. There is growing evidence that modular units ofdevelopment were highly preserved and recombined during evolution. We first consider a few examplesof modules well identifiable from morphology. Next we consider the more difficult issue of identifyingfunctional developmental modules. We dwell especially on modular control of locomotion to argue thatthe building blocks used to construct different locomotor behaviors are similar across several animalspecies, presumably related to ancestral neural networks of command. A recurrent theme fromcomparative studies is that the developmental addition of new premotor modules underlies thepostnatal acquisition and refinement of several different motor behaviors in vertebrates.
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