March 31, 2012 § 1 Comment
Results reported in the March 23rd issue of the journal Science reveal that Scripps Research Institute scientists may have established a method for partially controlling the memory. Their work provides further insight into how memories are formed, as well as offering new perspective on disorders such as schizophrenia and post-traumatic stress disorder.
The researchers were able to regulate neurons in the brains of mice, allowing them partial control over specific memories. This first step could lead to a better understanding of how memories form, possibly allowing scientists to weaken those harmful thoughts associated with conditions such as schizophrenia and post-traumatic stress disorder.
For decades, researchers have been aware that stimulating various regions of the brain can trigger behaviors and memories, but there has yet been no knowledge of how the way these brain functions – which inevitably lead to who we are as a person – develop naturally.
Study leader and Scripps Research neuroscientist Mark Mayford explains, “The question we’re ultimately interested in is: How does the activity of the brain represent the world? Understanding all this will help us understand what goes wrong in situations where you have inappropriate perceptions. It can also tell us where the brain changes with learning.”
The team accomplished this by inserting two genes into mice. One gene produces receptors that researchers can activate chemically to trigger specific neurons. They bonded that gene to a natural gene that only turns on in active neurons, such as those implicated in a particular memory as it forms or is recalled. Basically, this technique allowed the researchers to set up on-off switches on only those neurons involved in the formation of specific memories.
The study’s main experiment involved triggering the “on” switch in those neurons that are active in mice as they familiarized themselves with a new environment, designated Box A, which contained unique colors, smells, and textures. Next, the team gave the mice chemicals that would activate the neurons associated with memories for Box A, and placed the mice in a second environment – Box B. They found that the mice behaved as though they were forming an amalgamation memory of both environments. The chemicals needed to be activated while the mice were in Box B for them to exhibit indications of recognition. Neither the familiarization with Box B or the chemical switch was effective on its own for producing memory recall.
Mayford says, “We know from studies in both animals and humans that memories are not formed in isolation but are built up over years incorporating previously learned information. This study suggests that one way the brain performs this feat is to use the activity pattern of nerve cells from old memories and merge this with the activity produced during a new learning session.”
The team is currently working towards more fixed control over neurons, that will allow them to turn memories on and off so effectively that a mouse will think it is in Box A while in Box B. Mayford explains that once the process is better understood, the team will try to eventually target the perception process though drug treatment. This will be therapeutic for mental diseases such as schizophrenia and post-traumatic stress disorder, which involve false perceptions and disabling fears.
“Researchers Partially Control a Memory”. (March 23, 2012). Neuroscience News. March 25, 2012. http://neurosciencenews.com/synthetic-memory-trace-control-neurons-dreadd-receptors/.