Research wrests partial control of a memory

Scripps Research Institute scientists and their colleagues have successfully harnessed neurons in mouse brains, allowing them to at least partially control a specific memory. Though just an initial step, the researchers hope such work will eventually lead to better understanding of how memories form in the brain, and possibly even to ways to weaken harmful thoughts for those with conditions such as schizophrenia and post traumatic stress disorder.

The results are reported in the March 23, 2012 issue of the journal Science.

Researchers have known for decades that stimulating various regions of the brain can trigger behaviors and even memories. But understanding the way these brain functions develop and occur normally—effectively how we become who we are—has been a much more complex goal.

"The question we're ultimately interested in is: How does the activity of the brain represent the world?" said Scripps Research neuroscientist Mark Mayford, who led the new study. "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."

On-Off Switches and a Hybrid Memory

As a first step toward that end, the team set out to manipulate specific memories by inserting two genes into mice. One gene produces receptors that researchers can chemically trigger to activate a neuron. They tied this gene to a natural gene that turns on only in active , such as those involved in a particular as it forms, or as the memory is recalled. In other words, this technique allows the researchers to install on-off switches on only the neurons involved in the formation of specific memories.

For the study's main experiment, the team triggered the "on" switch in neurons active as mice were learning about a new environment, Box A, with distinct colors, smells and textures.

Next the team placed the mice in a second distinct environment—Box B—after giving them the chemical that would turn on the neurons associated with the memory for Box A. The researchers found the mice behaved as if they were forming a sort of hybrid memory that was part Box A and part Box B. The chemical switch needed to be turned on while the mice were in Box B for them to demonstrate signs of recognition. Alone neither being in Box B nor the chemical switch was effective in producing memory recall.

"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," Mayford said. "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."

Future Manipulation of the Past

The team is now making progress toward more precise control that will allow the scientists to turn one memory on and off at will so effectively that a mouse will in fact perceive itself to be in Box A when it's in Box B.

Once the processes are better understood, Mayford has ideas about how researchers might eventually target the perception process through drug treatment to deal with certain mental diseases such as and . With such problems, patients' brains are producing false perceptions or disabling fears. But drug treatments might target the neurons involved when a patient thinks about such fear, to turn off the neurons involved and interfere with the disruptive thought patterns.

More information: www.sciencemag.org/content/335/6075/1513.abstract

Related Stories

Neuroscientists identify a master controller of memory

Dec 22, 2011

When you experience a new event, your brain encodes a memory of it by altering the connections between neurons. This requires turning on many genes in those neurons. Now, MIT neuroscientists have identified ...

Memory formation triggered by stem cell development

Feb 23, 2012

Researchers at the RIKEN-MIT Center for Neural Circuit Genetics have discovered an answer to the long-standing mystery of how brain cells can both remember new memories while also maintaining older ones.

Recommended for you

Know the brain, and its axons, by the clothes they wear

Apr 18, 2014

(Medical Xpress)—It is widely know that the grey matter of the brain is grey because it is dense with cell bodies and capillaries. The white matter is almost entirely composed of lipid-based myelin, but ...

Turning off depression in the brain

Apr 17, 2014

Scientists have traced vulnerability to depression-like behaviors in mice to out-of-balance electrical activity inside neurons of the brain's reward circuit and experimentally reversed it – but there's ...

Rapid whole-brain imaging with single cell resolution

Apr 17, 2014

A major challenge of systems biology is understanding how phenomena at the cellular scale correlate with activity at the organism level. A concerted effort has been made especially in the brain, as scientists are aiming to ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

pauljpease
not rated yet Mar 22, 2012
Sounds like the memory technology in the movie "paycheck".
Argiod
not rated yet Mar 22, 2012
Here we go; the first stages of total mind control. Once any government can control our memories, we will not even remember who or what we are, and will become total puppets of said government. And with nanotechnology, it may be possible to alter everyone's memories with something as simple as arial spraying over our cities.

Of course, this is just my opinion; I could be wrong.
Telekinetic
not rated yet Mar 22, 2012
Argiod-

Television, computers, smart phones, and video games have already accomplished the "not remembering who and what we are", which WAS at one time a creature connected to and validated by nature. The electronic screen, with which I communicate with strangers- for what reason I'm not sure, is the new mirror that reflects a soul that has buried a life once lived under a star-filled sky.