Tuesday, February 2, 2010

How Do Rodents Make Decisions? A Nobel Laureate Speaks

Ion channels, the small tunnels that allow charged particles to flow through the cell membrane, play a significant role in various physiological functions. For neurobiologists, measuring the electric current associated with these ion channels proved to be a hard task, as a vast amount of information was lost due to noise.

The technique that was developed to overcome the loss of electric signals is called the patch clamp, and is one of the most widely used tools to study physiological processes on a molecular level today. One of the co-developers of this technique and a Nobel laureate, Dr. Bert Sakmann, was here on Friday to talk about his research at a seminar organized by the Duke Institute for Brain Sciences.

'We studied the neural connections in rodents using the Whisker model", Sakmann said to a packed auditorium.

The Whisker model was a whisker-dependent learning task in which the rodents had to make the decision whether to cross a small gap or not. "We wanted to know how many (neuronal) columns (of the brain were) involved in the decision-making process."

Through these experiments, Dr. Sakmann and fellow Nobel Laureate Dr. Erwin Neher identified certain cortical circuits that were activated during this decision-making process. "We measured the latency between stimulus and activation, and found there is a very precise and small latency."

They further discovered that decision-making is possible using a single column in the cortex. To measure the electric current associated within such single cells, they developed the patch clamp technique.

The patch clamp enabled the study of single ion channels and helped gain insight into the role of these channels in hormone regulation, heart diseases, epilepsy, and diabetes among others. A small video demonstrating the technique can be found below.

Sakmann and Neher received the Nobel Prize for Medicine in 1991 for their work.

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