Total recall: using light to create and erase memories

In Articles, Memory, Research by Mark Springel

The fundamental nature of memory has eluded philosophers and scientists for over two millennia. As early as 350 B.C., Aristotle conjectured that the mind was like a blank wax tablet, or tabula rasa, imprinted with one’s experiences but only made decipherable by associations between the distinct ideas etched into the tablet. As modern neuroscience emerged in the 20th century, doctors learned more about how memories were stored by studying patients with memory impairments, such as Henry Molaison (known as H.M.), who was unable to form long-term memories after the removal of a part of the brain called the hippocampus. At the same time, scientists explored how memories are formed by training animals to perform specific behaviors in the lab. These studies suggested that memory is physically represented in specific parts of the brain, and gave rise to the theory that discrete neural networks or even individual brain cells could make up a physical memory trace, or engram.

Recent advances in neuroscience and biotechnology allow researchers to find and manipulate memory engrams in mice and rats. Using a technology called optogenetics that allows immediate and precise control over individual brain cells, researchers have developed methods to selectively activate a memory, engineer a false memory, and strengthen or weaken a specific memory by delivering pulses of light to brain cells…

Read the full article here Harvard University