Friday, 18 July 2014

A Model System


Getting the right choice of words when describing anything is, truly, a tricky business. My style of research is often called "computational modelling" which roughly means "writing a computer program that mimics the function of a real system".

This idea seems straightforward enough. A flight simulator, for example, is a computational model. It gives pilots the impression that they are flying an aircraft, when what they are really doing is providing inputs to sets of equations that are a model of an aircraft. Notice that themodel aircraft is also referred to as a flight simulator, so the words model and simulator are close relatives.

So, I work to write programs that model the brain. Does this mean I am building a brain simulator? Or even an artificial brain?

The key difference is the level of understanding. Flight simulators are almost indistinguishable from the real thing because aircraft are relatively simple systems that humans designed and built to start with, we know how they work. In contrast we have absolutely no well formed idea of how large areas of the brain do what they do, not on the level that is necessary to produce a successful simulation of even the simplest sort, for even the simplest animals.

The work that I, and many others, do is designed precisely to help to develop, and test, new and imperfect ideas about how the brain might work, and any measure of success is very welcome! This sort of modelling - to explore hypotheses - is quite different to building a flight simulator which relies on well established and reliable science.

So my type of models are based on ideas, and if the models get even close to working, well, the ideas might have some merit. Models that are not based on clear underlying ideas are models of nothing. A red light should start to flash whenever the answer to "What idea are you testing?" gets dangerously close to "We just want to take the few things we know, multiply them half a billion times, wire it all up, and see what happens".

Model planes, and model brains - two almost unrelated concepts. We seem to be getting them confused.