Reconstructing the brain
by bits and bytes
Researchers have constructed a computer simulation of the
rat neocortex. What can such a simulation tell us about the
nature of human behavior?
Imagine an exquisitely detailed computer reconstruction of the rat brain, with more
than 50 layers of connected cells. This virtual microcircuit contains more than 200
different neural subtypes and nearly 40 million synapses. Its structure and behavior
are governed by meticulous neuroscientific data, collected at the molecular and
cellular levels. It can be used for experimental simulations to see what happens to
communications among neurons when biological parameters are altered.
Sounds like something from a science fiction novel. But it’s the first proof-of-concept model for the Blue Brain Project ( http://bluebrain.epfl.ch/), an ambitious
initiative with the ultimate goal of building a digital reconstruction of the human
brain. The project is based at the École Polytechnique Fédérale de Lausanne in
The idea for the project came from Henry Markram, PhD, who collected a massive
amount of data from studying a circuit in the rat primary somatosensory cortex. He
sought to pull it all together in a way that could further our understanding of how
the brain works. This first model of a small circuit in the rat neocortex took 10 years
to build, but experiments on the simulation are already providing key insights into
connection patterns among neurons linked to aggression and emotion.
While the model still requires more work, many researchers are excited about its
potential to help them better understand the brain in both health and disease, says
Sean Hill, PhD, who co-directs the Blue Brain Project.
“As we get more data-driven definitions of disease, we can use those signatures to
better understand what may be going awry in depression or schizophrenia,” he says.
“But the important thing is we give value to the data and create an ecosystem where
that data is valued and used to better understand how the brain works.”
Some researchers are less convinced of its value. The Blue Brain Project has been
criticized for its data-driven, rather than theory-driven approach and narrow focus.
But Andrew Rossi, PhD, of the Theoretical and Computational Neuroscience Program
at the National Institute of Mental Health, says that the value of more computational,
data-driven approaches (what’s now called in silico neuroscience) is becoming more
Neurocomputational and data-driven approaches can help researchers to expand
their thinking, Rossi says. “These approaches will allow us to ask better, more precise
questions about the normal function of the brain and what occurs in disorders of
cognition — and with luck, give us new leads about where we might look to find those
answers,” he says.
— Kayt Sukel
To watch a video about the Blue Brain Project, go to
Neural slice preview: Simulation
of electrical activity in a “virtual
brain slice” formed from seven
unitary digital reconstructions of