Team isolates nerve cells involved in storing long term memory and gene proteins associated with them

February 10, 2012 by Bob Yirka report
Identification of common neurons in two Gal4 lines. Image: Science DOI: 10.1126/science.1212735

(Medical Xpress) -- A research team in Taiwan has succeeded in isolating two nerve cells in fruit fly brains that are believed to be the major players in allowing for the formation of long term memories. Furthermore, they’ve also found the genes that appear to be essential in creating related proteins that allow such memories to be saved. They have published a paper describing their work in Science.

To better understand human functions such as memory processing, researchers look to much less complicated brains as a model. The hope is that whatever is learned in studying simpler brains, can at some point be applied to larger more complicated ones such as ours. Because of this, researchers quite often study fruit fly brains. This is because they have very small brains, but still possess some important brain skills, such as the ability to form both long and short term memory.

To study in fruit flies, the team used a small enclosure divided into regions, or wings. In one wing, odors were presented that attract the fruit fly, when it arrived it was given a mild electric shock. The other wing was safe. Over time, the fruit flies came to remember that the odor in one room led to an unpleasant result, while the other did not.

The video will load shortly
Visualizing de novo KAEDE synthesis in per neurons during ZT0-6 and ZT12-18, respectively. Movie: Science, DOI: 10.1126/science.1212735

Then, to find out which part of the brain was used to store those memories, the team used a tiny heating device that allowed them to selectively warm parts of the brain, which in turn prevent the kinds of proteins from synthesizing in neurons that are known to be needed to store long term memories. By testing neurons in one part of the brain after another, they narrowed down the possibilities until landing on two called dorsal-anterior-lateral (DAL) neurons. Heating these two, which are not located in the mushroom body, as expected, but outside of it, they found that long term memory was disabled. This meant they’d found which neurons were mainly responsible for allowing for the storage of long term memories.

Once they had that information, they team next genetically altered some to cause their brain cells to glow green, and then to red when exposed to UV light. This allowed them to follow protein growth in the fruit fly brains over time. When they applied this to the DAL neurons, they were able to trace the specific genes responsible for their formation.

Explore further: Long-term memory controls discovered

More information: Visualizing Long-Term Memory Formation in Two Neurons of the Drosophila Brain, Science 10 February 2012:
Vol. 335 no. 6069 pp. 678-685. DOI: 10.1126/science.1212735

ABSTRACT
Long-term memory (LTM) depends on the synthesis of new proteins. Using a temperature-sensitive ribosome-inactivating toxin to acutely inhibit protein synthesis, we screened individual neurons making new proteins after olfactory associative conditioning in Drosophila. Surprisingly, LTM was impaired after inhibiting protein synthesis in two dorsal-anterior-lateral (DAL) neurons but not in the mushroom body (MB), which is considered the adult learning and memory center. Using a photoconvertible fluorescent protein KAEDE to report de novo protein synthesis, we have directly visualized cyclic adenosine monophosphate (cAMP) response element–binding protein (CREB)–dependent transcriptional activation of calcium/calmodulin-dependent protein kinase II and period genes in the DAL neurons after spaced but not massed training. Memory retention was impaired by blocking neural output in DAL during retrieval but not during acquisition or consolidation. These findings suggest an extra-MB memory circuit in Drosophila: LTM consolidation (MB to DAL), storage (DAL), and retrieval (DAL to MB).

Related Stories

Long-term memory controls discovered

January 13, 2006

Harvard biologists say research on the long-term memory in fruit flies may lead to new therapeutics to treat human memory loss.

Computer Technique Creates Map of a Fruit Fly Brain

April 12, 2010

Researchers, led by Hanchuan Peng, at the Janelia Farm Research Campus at the Howard Hughes Medical Institute in Ashburn, Virginia are working to map the fruit fly brain in a way that highlights how neurons work together. ...

Scientists identify mechanism of long-term memory

April 13, 2011

Using advanced imaging technology, scientists from the Florida campus of The Scripps Research Institute have identified a change in chemical influx into a specific set of neurons in the common fruit fly that is fundamental ...

Sleep switch found in fruit flies

June 23, 2011

Rather than count sheep, drink warm milk or listen to soothing music, many insomniacs probably wish for a switch they could flick to put themselves to sleep.

Recommended for you

Next steps in understanding brain function

August 26, 2016

The most complex piece of matter in the known universe is the brain. Neuroscientists have recently taken on the challenge to understand brain function from its intricate anatomy and structure. There is no sure way to go about ...

Scientists map brain's action center

August 25, 2016

When you reach for that pan of brownies, a ball-shaped brain structure called the striatum is critical for controlling your movement toward the reward. A healthy striatum also helps you stop yourself when you've had enough.

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

wealthychef
not rated yet Feb 10, 2012
Part of what I call "higher order science," which is the science which moves science along. If this were to lead to longer and better memories in humans, without causing insanity as you cannot forget your first girlfriend or the time your puppy died, then we could have as one effect, smarter scientists, leading to better science... a virtuous circle.
Tausch
not rated yet Feb 11, 2012
'Learning' takes on new meaning in light of total recall.
Insanity is history repeating itself - war comes to mind.

Kudos to the research and researchers.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.