Imagine, as a mouse, that you are quietly scratching a cage when suddenly faced with a choice. From the corner of your eye you can see a juicy cockroach. Smelling or even tasting seems tempting. But a little further, there’s also one more thing, something strange that you’ve never seen before. Do you take the lead or do you prefer the popular game of cricket?
Researchers at the Netherlands Institute of Neuroscience have discovered an area in the mouse brain that encourages probing behavior. When this circuit is stimulated, mice tend to approach new congeners or objects – such as an eraser or a piece of sponge – more aggressively and conduct more intensive exploratory research. When they shut down this group of cells, that investigative stance disappeared, they reported in the Journal of Commerce on Thursday Science.
A prerequisite for learning
Neuroscientist Alexander Heimel of the Institute for Neuroscience says it is not yet known whether this brain region has the same function in humans. “But this study in mice shows that it will be very interesting to look at that.”
Curiosity is a prerequisite for survival and learning from humans and animals. Bold research is essential to exploring new food sources and gaining new knowledge. But it is not entirely clear how the impulse originates in the brain to approach the unknown. However, many different brain regions are involved in humans.
It was a coincidence, Heimel says, that the mice ended up in this particular brain region. The neuroscientist usually deals with vision in the rodent brain. Through this research, he and his colleagues discovered Uncertain areaThe area of uncertainty, so called because it wasn’t at all clear what its function was. Heimel: “I only heard of it four years ago, and it’s now a very popular field of research.”
The researchers decided to stimulate the area using optogenetics, which can be used to control the activity of individual brain cells. When they turned on the cells in that area in the mice, they immediately saw, “They were chasing after things, nibbling on them. They approached a big ball in their cage and found it a bit frightening at first.” The researchers found this startling.
For hunting or not?
But in the meantime, the foreign colleagues discovered exactly the same thing and concluded in a scientific article that mice were hunting. In Heimel’s lab, the researchers were not satisfied with this explanation. They run a number of experiments that have shown that mice do not hunt.
So they put the mice in a cockroach cage, along with something unknown, like a piece of plastic. Their study found that mice with increased activity in the unknown region spent significantly more time with the unknown. The mice were really curious when sniffed, bitten, gnawed, pulled into a cage. Even without stimulation using optogenetics, the researchers saw that these cells in the cell-free region became more active during the exploratory behavior.
In another experiment an unknown homogenate was placed in the cage. Same effect. “We’ve seen a lot of this research behavior in mice that they didn’t know yet compared to mice that they had known for some time.” Because of the various experiments, neuroscientists have ruled out that mice only want to eat, bite, or hunt, Heimel says.
“This subset of cells in the unfavorable region actually says: Go out and see what’s new.” These cells do this by suppressing fear in another area of the brain: “They are actually inhibitory cells.” In mice, the Incerta region plays a role in the balance between fear of the new unknown and curiosity.
People also have an unexpected territory, Hemel says. “From an evolutionary point of view, this is a very ancient region of the brain. But in humans there are still huge layers above it.” They are located between the hypothalamus and the hypothalamus, and are important brain terminals in which all kinds of basic instinctive functions are controlled, such as thirst, hunger, fear and stress.
Clearly, investigative behavior and fear inhibition are also linked in the human brain, Heimel says. But because the Inserta region is very deep in the brain, it is not easy to access, for example, with a functional MRI scan, and therefore difficult to examine.
However, the discovery of the role of zona incerta is a reason for further research into this matter, as American researchers Zahra Farahbakhsh and Cody Siciliano wrote in response to the Dutch work. The research takes the field “one step closer to understanding one of the most prevalent and influential innate drivers of human and animal behavior,” they say.
These two researchers also suggest that searching for new experiences and sensations in extreme forms can lead to addiction, for example, and thus this research could lead to a greater understanding of this matter. But Alexander Heimel still thinks the move is a little big. “Curiosity is really about reward. Reward and addiction are closely related. But based on this research in mice, that’s a very big jump.”
The scientist presses the button and the mouse is either happy or afraid
With a flash of light in their brain, Karl Deisseroth can induce hallucinations, thirst and euphoria in mice and make them disappear again. The American neuroscientist was awarded the Heineken Prize for Medicine this month.
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