Mapping brain networks
24 February 2011
US scientists have created a model of the ring-shaped networks of neurons in the brain, which could help researchers to understand small changes within diseased brain cells.
Henry Zeringue, and colleagues at the University of Pittsburgh, developed the model to enable the study of brain circuitry in an in vitro system instead of using brain slices.
In the brain, neuronal networks make up the cortex, which is responsible for holding traces of memory for short time periods. The cortex does this using persistent activity in the network, which can last from milliseconds to seconds. In neurological diseases, such as Alzheimer's disease, subtle changes in this activity take years, or even decades, to become clinically detectable. Most studies only explore the electrical properties of a single neuron or the connection between two neurons. Until now, there hasn't been a good model to study network activity in vitro.
The ring structure of the neuron networks was prepared by stamping proteins onto a glass substrate and growing neurons on the proteins
Zeringue's team stamped proteins onto glass substrates in a ring shape. Rat neurons were grown on the proteins, making a network of 40-60 neurons. To test the neurons' ability to transmit a signal around the ring, the team used an electrical field to stimulate one of the neurons and followed the signal's progress. To do this, they injected a fluorescent dye into the system, which responds when transmitter molecules are released. They captured the signal's progress with a fluorescence detection camera and found that the signal continued around the ring for several seconds before a gradual decay.
'[This work] is an excellent example of using simplified circuits to understand processes in the brain,' says Elisha Moses, an expert in the physics of complex systems at the Weizmann Institute of Science, Israel.
Zeringue and his team are considering using their platform to characterise network-level changes based on small experimental perturbations, like changes in network geometry or expression of mutant proteins in 10 per cent of the neurons. 'Deciphering the relationship between the connectivity of the neurons and the activity in the ring culture will be challenging and unravelling the connections between the neurons may still prove to be a daunting task,' he concludes.
Interesting? Spread the word using the 'tools' menu on the left.
Link to journal article
Ring-shaped neuronal networks: a platform to study persistent activity
Ashwin Vishwanathan, Guo-Qiang Bi and Henry C. Zeringue, Lab Chip, 2011, 11, 1081
Also of interest
The ability to wipe out traumatic memories is just around the corner. Katrina Megget looks into the science of forgetting
24 February 2011
Model ring-shaped neuronal networks for unravelling memory, learning and cognition processes
Instant insight: Alzheimer's: untangling the facts
06 August 2009
Cures for Alzheimer's may come from understanding its chemistry. Arvi Rauk examines the disease at the molecular level
Attacking Alzheimer's disease
06 May 2009
Fresh hope in battling Alzheimer's disease with three-pronged attack
23 March 2010
For many years, beta amyloid has been blamed for causing Alzheimer's - but could it also be protecting us from infection?
Comment on this story at the Chemistry World blog
Read other posts and join in the discussion
External links will open in a new browser window