I get lost. A lot.

For this reason, I was very excited when I picked up last month's Science, in which researchers from University College London reported that sense of direction is innate in newborn rats. Their work is an important starting point in understanding how humans develop a concept of space.

This was big news for me. Maybe, I thought to myself, I was one of the unlucky few who had been cursed with bad biology. Could it be that my constant disorientation wasn't actually my fault?
In the study, researchers implanted electrodes, which can detect the electrical activity of neurons, in newborn rats. The scientists specifically targeted the hippocampus, a structure found in the brain that is associated with spatial orientation and memory.

"Our question was 'how do these representations of space come about during the development of these animals?'" said study author Dr. Francesca Cacucci, a research fellow at University College London, during our phone conversation.

In these experiments, Cacucci and colleagues monitored rats' brain activity as the rats explored a wooden box scattered with treats. The scientists looked at three cell types in particular:

•    Directional cells, neurons that tell an animal where it is headed. "They don't respond to magnetic fields. They don't work like a compass," Cacucci said. "But they extract information from features of the environment." Right now, for instance, your directional cells are telling you that are facing your computer.

•    Place cells, which give animals a sense of their precise position in space. Hopefully, your place cells are telling you that you're sitting in your chair, with a cold drink on your right and a fan on your left.

•    Grid cells, which give an animal an idea of how far it has traveled in a given space. Perhaps your grid cells are telling you that you've walked across the room to sit at your computer and read this blog post.

Altogether, these three cell types tell an animal which direction it is facing, where it is, and how far it has traveled.

In this study, the scientists were surprised to learn that these cells develop early on and in a precise order.

"Directional cells are the first to emerge during development. We found some [cells] that are very much like what you would see in an adult rat, in animals that were just 2 weeks old," said Cacucci. "That is quite surprising because this is a time when the animal hasn't had a chance to explore its surroundings and the environment at large. These animals are mainly confined to the nest when they are so young."

Place cells develop later.

"The place cells are also there very early on, but they are a bit fuzzy. So, instead of giving the animal a very precise idea of where it is, it is a bit more spread out," Cacucci said. 

It's like using one of those novelty cartoon maps they give out at tourism centers. You can get a general sense of where you are, but it's not as accurate as your GPS or a detailed road map.
Grid cells are the last to emerge.

"To our astonishment, there don't seem to be grid cells before the animals turn 20-21 days old," Cacucci said.  

Until now, scientists did not have an accurate understanding of how these different cell types emerged or whether they relied on each other during development. For instance, it was generally assumed that grid cells were inputs to place cells and developed earlier.

"Our data says 'uh-uh, this can't be right,'" said Cacucci. "Those kinds of ideas need to be revised."

The group also varied the ages of the animals and gave some rats multiple chances to explore and learn the box.

"All that mattered was the age of the animals," said Cacucci. "It didn't matter if the animals were experienced or not very experienced in the box. They didn't have better or worse cells or spatial orientation."

So, it would appear that the rat's early sense of space is inherent, rather than learned.

With this in mind, is it possible that I am just stuck with deficient or poorly-developed directional, place and grid cells? Is that why I keep getting lost everywhere I go?

According to Cacucci, it's unlikely. The group didn't find any major differences among rats that were the same age.

"We didn't find that some rats had brilliant directional cells and some had poor ones" she said. "On the basis of our results alone, we think that the differences in [adult human] abilities are not caused by cells, but maybe it has more to do with strategies you adopt when you learn to navigate through a specific environment."

These strategies include memorizing landmarks or studying maps before venturing out into a new place.

Even though Cacucci's findings shoot down any possibility of blaming my less-than-perfect navigational skills on science, this work could help doctors spot brain damage in young children.

Because the hippocampus (where populations of these directional, place and grid cells reside) is sensitive to oxygen deprivation, many children who experienced difficult births can go on to suffer from amnesia and constant spatial disorientation.

"They won't be able to remember episodes from their lives," Cacucci said. "They will be always unable to navigate in space and orient themselves. You can imagine how much of a burden it is for them."

This form of amnesia is problematic because it is often diagnosed later in life, when these children reach school age.

"We are hoping, though this is far in the future, that our work might help in picking out these kids earlier," Cacucci said. "The brains of children are very plastic. The earlier you get them, the more you can hope and try to prevent amnesia and develop strategies to help them."

Intern Rebecca Cheung is a graduate student at the University of British Columbia's School of Journalism.
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