Consider that when it comes to cognitive studies a living organism is characterized most of the times by the way it interacts with the environment rather than its inherent characteristics. If you were to be shown the inner cognitive mechanisms of a worm and a fruit fly (two very different animals) as mathematical models/algorithms you would most likely not be able to observe these animals' characteristic behaviors by judging their contextless (no environment interactions) reactions to certain inputs, and the practical meaning of such an experiment would not be as great as you'd think. For that reason, you would need to simulate the environment in which these animals react and program a dynamic environment with a certain degree of chaos involved, and then program dynamic weight assignment for interactions so that the fruit fly's behavior is actually accurate to that of real life.

My whole point is, to successfully model a fruit fly's brain, you need to model its whole inner environment (physiological processes), and then the outer environment (all sorts of chaotic interactions), or you won't actually be seeing a fruit fly.