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Lab tweet:

Scientific goals

In our lab, we want to understand the structure of neocortical circuits. background

Our goal is to measure the connectivity between thousands of nerve cells in the cerebral cortex, and to understand the computations that this network can perform.

More specifically, we are studying a piece of mouse somatosensory cortex, which probably analyzes the contact between the main whiskers on the snout of the animal and real-world objects (trees, apples, other mice).

Our work was recently featured in a Nature article. Also have a look at our Brain Games, coming soon on www.brainflight.org.



For an introductory movie about what we do and why we do it, please refer to Moritz speaking at the TEDxVienna conference 2011 (youtube).


More detailed information can be found in the following review articles:


Methods

The dense reconstruction of neuronal circuits has become possible with the invention of the serial blockface scanning electron microscope (SBEM).

This new microscope combines a device to slice the nerve tissue in extremely thin slices (~25 nm thickness) with a scanning electron microscope to efficiently image the tissue at very high resolution. All of this is completely automated. These experiments run for weeks and months, and are therefore very challenging.

Once the images are acquired, the data has to be reconstructed. That is, the nerve cells with all their elaborate processes (the wires of the brain) have to be extracted, and synapses have to be detected.

Based on tools Moritz developed in his postdoctoral work, we are able to crowd source the reconstruction task, and thus reconstruct circuits of considerable size.

For high-throughput nerve cell reconstruction, we use a combination of humans (currently more than 100 undergraduate students) and machines.


Background

The main part of the human (and most mammalian) brains is the outer shell directly beneath the skull, called the cerebral cortex (or neocortex). This is where we think, see, hear, and probably love.

The neocortex is packed with nerve cells. Even a small piece the size of, say, a grain of sand, contains several thousands of nerve cells. What is most stunning, though, is not the sheer number of nerve cells (the liver also contains a lot of cells), but the extreme level of connectivity between them.

Nerve cells are like humans: they talk directly to at least hundreds, if not thousands of their kind. The network of nerve cells is very complex, and it is very likely that it is this extreme complexity that makes the brain so powerful.

Yet, we don't know what the connectivity between large clusters of nerve cells in the cortex looks like.

Therefore, our goal is to measure the connectivity between thousands of nerve cells in the cerebral cortex, and to understand the computations that this network can perform.


© Moritz Helmstaedter
Max Planck Institute of Neurobiology
last modified 2014/03/11