How brain helps retain memories revealed

Scientists have revealed in an image study that dendrites in specific neurons called 'place cells' were critical in keeping memories and allowed some experiences to be remembered while others are forgotten.

In the brain's hippocampus, there were hundreds of thousands of 'place cells'-neurons essential to the brain's GPS system. Daniel A. Dombeck and Mark E. J. Sheffield were the first to image the activity of individual dendrites in place cells.

Dombeck and Sheffield built their own laser scanning microscope that could image neurons on multiple planes. They then studied individual animals that navigated (on a trackball) a virtual reality maze constructed using the video game Quake II.

They have seen that dendrites were not always activated when the cell body was activated in a neuron. Signals were produced in the dendrites (used to store information) and signals within the neuron cell body (used to compute and transmit information) could be either highly synchronized or desynchronized depending on how well the neurons remembered different features of the maze.

Their findings have contributed to our understanding of how the brain represented the world around it and also pointed to dendrites as a new potential target for therapeutics to combat memory deficits and debilitating diseases, such as Alzheimer's disease (AD).

In the brain's hippocampus, there were hundreds of thousands of 'place cells'-neurons essential to the brain's GPS system. Dombeck and Sheffield were the first to image the activity of individual dendrites in place cells.

Neuroscientist John O'Keefe had discovered place cells in 1971 (and received this year's Nobel Prize in physiology and medicine).

Scientists have long believed that the neuronal tasks of computing and storing information were connected-when neurons computed information, they were also storing it, and vice versa. The Northwestern study provided evidence against this classic view of neuronal function.

The Northwestern study was published in the journal Nature.