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Scientists Find a Way to Erase Memories of Drug Use in Addicted Mice

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Scientists have found a way to erase very specific memories in mouse brains, helping drug-addicted lab rodents recover. 

Following up on a similar study they published in 2013, researchers from the Scripps Research Institute in Florida were able to selectively erase memories of methamphetamine in mice using a drug that disrupts a memory-related protein in the brain. 

In previous studies, the researchers found that memories of drug use are not stored in the same way as other memories. Actin, a protein that supports connections between neurons, normally stabilizes within a few minutes of a typical experience (like eating a really great dessert), but when it comes to drug memories like the thought of taking your first hit of meth, actin filaments keep changing in size, strengthening the connections between neurons even days after the original event. 

Neurobiologist Courtney Miller, one of the authors of the recent study in the journal Molecular Psychiatry, explains that a drug administered in the lab can be used to target only memories associated with addiction because of this unique instability. She writes in an email to mental_floss that “unlike the memory for food reward, the actin is cycling and, therefore, open to a breakdown of actin filaments (and consequently, spines) when the monomers are sequestered by Latrunculin [the treatment drug].” When the researchers targeted nonmuscle myosin IIB, a protein that drives actin polymerization (the process by which actin changes during memory storage), they were able to make lab mice forget memories associated with meth, but not erase other memories, such as those associated with a scary experience. 

Meth users might have developed associations with seemingly banal activities like handling money or chewing gum, meaning that reminders of their drug use (and the cravings that come along with them) are constantly lurking in everyday life. This technique removes the triggering memories that might induce drug cravings, helping prevent relapse, and could be a useful addition to rehabilitation therapy. 

However, the treatment is a long way from being ready for use by people. The researchers hope to start human trials in the next five years. And that’s if it even makes it to human trials—in cancer research, the success rate of a transfer from animal to human models is less than eight percent, and other fields face similar disappointments with treatments developed in animal models. 

[h/t: Washington Post]

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Animals
Goldfish Can Get Depressed, Too
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Don’t believe what Pixar is trying to sell you: Fish are not exactly brimming with personality. In aquariums, they tend to swim in circles, sucking up fragments of food and ducking around miniature treasure chests. To a layperson, fish don’t appear to possess concepts of happy, or sad, or anything in between—they just seem to exist.

This, researchers say, is not quite accurate. Speaking with The New York Times, Julian Pittman, a professor at the Department of Biological and Environmental Sciences at Troy University, says that fish not only suffer from depression, they can be easily diagnosed. Zebrafish dropped into a new tank who linger at the bottom are probably sad; those who enthusiastically explore the upper half are not.

In Pittman’s studies, fish depression can be induced by getting them “drunk” on ethanol, then cutting off the supply, resulting in withdrawal. These fish mope around the tank floor until they’re given antidepressants, at which point they begin happily swimming near the surface again.

It’s impossible to correlate fish depression with that of a human, but Pittman believes the symptoms in fish—losing interest in exploring and eating—makes them viable candidates for exploring neuroscience and perhaps drawing conclusions that will be beneficial in the land-dwelling population.

In the meantime, you can help ward off fish blues by keeping them busy—having obstacles to swim through and intriguing areas of a tank to explore. Just like humans, staying active and engaged can boost their mental health.

[h/t The New York Times]

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Pigeons Are Secretly Brilliant Birds That Understand Space and Time, Study Finds
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Of all the birds in the world, the pigeon draws the most ire. Despite their reputation as brainless “rats with wings,” though, they’re actually pretty brilliant (and beautiful) animals. A new study adds more evidence that the family of birds known as pigeons are some of the smartest birds around, as Quartz alerts us.

In addition to being able to distinguish English vocabulary from nonsense words, spot cancer, and tell a Monet from a Picasso, pigeons can understand abstract concepts like space and time, according to the new study published in Current Biology. Their brains just do it in a slightly different way than humans’ do.

Researchers at the University of Iowa set up an experiment where they showed pigeons a computer screen featuring a static horizontal line. The birds were supposed to evaluate the length of the line (either 6 centimeters or 24 centimeters) or the amount of time they saw it (either 2 or 8 seconds). The birds perceived "the longer lines to have longer duration, and lines longer in duration to also be longer in length," according to a press release. This suggests that the concepts are processed in the same region of the brain—as they are in the brains of humans and other primates.

But that abstract thinking doesn’t occur in the same way in bird brains as it does in ours. In humans, perceiving space and time is linked to a region of the brain called the parietal cortex, which the pigeon brains lack entirely. So their brains have to have some other way of processing the concepts.

The study didn’t determine how, exactly, pigeons achieve this cognitive feat, but it’s clear that some other aspect of the central nervous system must be controlling it. That also opens up the possibility that other non-mammal animals can perceive space and time, too, expanding how we think of other animals’ cognitive capabilities.

[h/t Quartz]

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