  Since they became observable, neuron morphologies have been informally
compared with biological trees but they are studied by distinct communities,
neuroscientists, and ecologists. The apparent structural similarity suggests
there may be common quantitative rules and constraints. However, there are also
reasons to believe they should be different. For example, while the
environments of trees may be relatively simple, neurons are constructed by a
complex iterative program where synapses are made and pruned. This complexity
may make neurons less self-similar than trees. Here we test this hypothesis by
comparing the features of segmented sub-trees with those of the whole tree. We
indeed find more self-similarity within actual trees than neurons. At the same
time, we find that many other features are somewhat comparable across the two.
Investigation of shapes and behaviors promises new ways of conceptualizing the
form-function link.
