New Scientist has a report that IBM and the Ecole Polytecnique F?d?rale de Lausanne in Switzerland are getting together to produce a simulation of a whole human brain using a custom-built supercomputer. Apart from the sheer audacity of this project, what is interesting is that they intend to model individual neurons using a detailed bio-electrical model. Normally, neurons are modelled as simple idealised object, but but this simulation will be based on a model of how real neurons behave electrically.
For over a decade [they] have been building a database of the neural architecture of the neocortex, the largest and most complex part of mammalian brains.
Using pioneering techniques, they have studied precisely how individual neurons behave electrically and built up a set of rules for how different types of neurons connect to one another.
Very thin slices of mouse brain were kept alive under a microscope and probed electrically before being stained to reveal the synaptic, or nerve, connections
I find this interesting because, back in the late 80’s I worked for a year at the (now defunct) IBM UK Scientific Centre in Winchester. For a lot of that time I was involved with a project at Southampton University to model the electrical characteristics of Hippocampal neurons taken from rats. The brain samples were sliced, probed, and stained just as described in the New Scientist article. The reason for staining them is so that the neuron’s shape can be mapped, which allows you to determine their volume and dendrite crossectional area – which in turn determine electrical properties such as capacitance and firing latency (if I remember right). I wrote the software that semi-automatically built a 3D ball-and-cone model model of the cell from a set of overlapping scans of the brain slices.
Back in 1989 the best we could do was simulate a single neuron: anything more was just computationally infeasible. Now, just fifteen years later, it makes sense to talk about working towards simulating an entire brain in ten years time. How things change.