Scientists Have Obtained the First Images of How Memory Forms

The latest technological achievements enable us to track down the biochemical and physical processes found behind the memory formation.

But now, for the first time, we have an image of how our memories form physically, due to a team from the University of California, Irvine. The research could explain the mechanisms of memory loss in cognitive disorders.

Neuroscientists have determined, after 30 years of experimentation, that the brain process of long-term potentiation (LTP) encodes the memory formed each day.

The images, presented in the Journal of Neuroscience, show how the size and shape of synapses were modified by LTP. "The way is now open to mapping where in the brain memories are laid down," said co-author Gary Lynch, a professor of psychiatry and human behavior. "Seeing memory-related physical changes to synapses means that we can at last use mouse models to test if the effects of retardation, aging and various cognitive disorders involve a specific, long-suspected defect in the connections between cortical neurons."

The team induced LTP in the rat and mouse brain tissue by stimulating synapses with a memory forming rhythm. Brain slices were sectioned and marked with one antibody molecule that binds to proteins activated in LTP and a second one that labels the synapses. The bound antibodies allowed the visualization and measurement of the synapses.

The research also links LTP impairments to memory loss in the early phases of Huntington's disease, an irreversible neurodegenerative condition. The team found that LTP structures encoding memory are defective in mouse models of Huntington's disease. The synaptic defects can be treated by employing a brain growth factor released in the synapses.

The team is now checking if LTP defects encountered in mouse models are also present in common types of human mental retardation.