1. A computer-implemented method for growing a simulated neural circuit, the method comprising: generating, using at least one computer, a first array of simulated neurons having trees of output branches in a simulated physical volume; generating, using the at least one computer, a second array of simulated neurons having trees of input branches in the simulated physical volume; growing, using the at least one computer, the output branches of one or more of the simulated neurons of the first array; growing, using the at least one computer, the input branches of one or more of the simulated neurons of the second array; and forming, using the at least one computer, connections between individual output branches of the simulated neurons of the first array and individual input branches of the simulated neurons of the second array that grow to within a vicinity of each other in the simulated physical volume, wherein growing the output branches of one or more of the simulated neurons of the first array comprises guiding the growth of the output branches based on a measure of output branch density.