How to preserve competing memories by zapping your brain

July 12, 2011 by Amara D. Angelica

I think I'm ready for midterms now.... (Credit: stock image)

Attention, mind-control victims: mad scientists want to zap your brain. But you knew that.

It’s a problem every student has when cramming for an exam: some of the information is usually forgotten. The common belief is that your brain simply doesn’t have the capacity necessary to process both memories in quick succession. But is that true?

Researchers at Beth Israel Deaconess Medical Center (BIDMC) decided to find out: what if you could disrupt the interference, using transcranial magnetic stimulation (TMS), which uses a magnetic simulator to generate a pulsed magnetic field that creates a flow of current in the brain?

So the researchers studied a group of 120 college-age students who performed two concurrent memory tests. The first involved a finger-tapping motor skills task, the second a declarative memory task in which participants memorized a series of words. They didn’t do too well.

Then they tried it again. This time, they administered TMS to the dorsolateral prefrontal cortex and the primary motor cortex of the brain. Et voilá, both memories magically remained intact! (The scientists speculated that sleep may have the same function, of reducing interference.)

Hmmm, so could I like, put a refrigerator magnet on my head to remember stuff? Er, no.

Ref.: Daniel A Cohen & Edwin M Robertson, Preventing interference between different memory tasks, Nature Neuroscience (2011) [DOI:10.1038/nn.2840]

Messing with fly minds

In related news Monday, scientists from the Max Planck Institute of Neurobiology in Martinsried and from the Ecole SupĂ©rieure de Physique et de Chimie Industrielles in Paris and an international team of colleagues announced they have unraveled how associative memories are actually “read out” in the brain, and why you can’t remember the name of the person you just met.

"Must have turned me into something else ...." (credit: 20th Century Fox)

The trick: fruit flies. Unlike people, they only have 100,000 brain cells, which allows scientists to decode processes at the individual cell level. So the neurobiologists (not the zappers, different ones this time) conditioned fruit flies to associate a certain odor with a mild electrical stimulus.

After repeating this conditioning experiment only once, the flies started turning away from the odor.

The scientists then temporarily deactivated MB-V2 nerve cells, and they noted that the flies did not turn away from the odor this time. Ah ha! MB-V2 neurons are involved in some kind of memory “read-out” pathway.

No word if Jeff Goldblum was involved in the experiment.

So wait, what if we stimulate your MB-V2 neurons at the same time that we zap your brain….?

Ref.: Hiromu Tanimoto & Thomas Preat, et al., Mushroom body efferent neurons responsible for aversive olfactory memory retrieval in Drosophila, Nature Neuroscience, 2011 Jun 19;14(7):903-10. [DOI: 10.1038/nn.2846]