Scientists retrieve lost memories using optogenetics
- 2015-05-28
- Science Daily
In a paper published today in the journal Science, researchers at MIT reveal that they were able to reactivate memories that could not otherwise be retrieved, using a technology known as optogenetics.
The finding answers a fiercely debated question in neuroscience as to the nature of amnesia, according to Susumu Tonegawa, the Picower Professor in MIT's Department of Biology and director of the RIKEN-MIT Center at the Picower Institute for Learning and Memory, who directed the research by lead authors Tomas Ryan, Dheeraj Roy, and Michelle Pignatelli.
Neuroscience researchers have for many years debated whether retrograde amnesia -- which follows traumatic injury, stress, or diseases such as Alzheimer's -- is caused by damage to specific brain cells, meaning a memory cannot be stored, or if access to that memory is somehow blocked, preventing its recall.
"The majority of researchers have favored the storage theory, but we have shown in this paper that this majority theory is probably wrong," Tonegawa says. "Amnesia is a problem of retrieval impairment."
Memory researchers have previously speculated that somewhere in the brain network is a population of neurons that are activated during the process of acquiring a memory, causing enduring physical or chemical changes.
If these groups of neurons are subsequently reactivated by a trigger such as a particular sight or smell, for example, the entire memory is recalled. These neurons are known as "memory engram cells."