Posted By cYw22 on Jun 5, 2014 | 11 comments

Everyone has experienced the gripping fear of being lost. Whether it is accidentally wandering too far from Mom in a department store or making a wrong turn down a dead-end street, getting lost is a normal part of life. We make mistakes, can’t find our way for a few moments, but we always end up making our way back to safety soon enough. For some people, though, that feeling of being lost is not a rare event, but a daily occurrence. For those suffering from Developmental Topographical Disorientation (DTD), not knowing where they are is as normal as breathing.

Path integration navigation is what allows you to get up in middle of the night and get a glass of water while you are barely conscious.
[Graphic by Staff Illustrator]

Meet Sharon Roseman, who has lived in Denver, Colorado for over twenty years. In that time span, most people would know their neighborhoods like the back of their hands, but for Ms. Roseman, just remembering where her kitchen is located in her house is a struggle. In a New York Times documentary, Ms. Roseman describes, “It’s almost as if somebody picks up the entire world, turns it, and sets it back down.” (Siddique, 2013).

But what exactly is DTD? To answer this question, we first need to determine exactly how people remember directions and locations. Navigation can be grouped into two categories: landmark orientation and path integration (Iaria, 2011). Landmark orientation takes geographic and manmade features and turns them into signs telling you when to turn or move straight ahead. For example, you might know that your friend’s street is the second left after the bakery. In this case, the bakery is a landmark which helps you decide where to go. Path integration relies more on memorization of how many turns a person needs to make or how far they need to move. This type of navigation is what allows you to get up in middle of the night and get a glass of water without banging into walls or tripping over furniture. Your brain automatically remembers how many turns to make to get out of your room or steps to take down the hall, so even in your sleepy state, you can find your way.

Luckily for you, your brain seamlessly combines both landmark orientation and path integration so you can move about without thinking too much. Unfortunately, for some people the brain simply can’t retain all this information. Neuroscientist Giuseppe Iaria of the University of Calgary, the man who discovered DTD, explains that patients with DTD can’t form “cognitive maps,” meaning they cannot mentally visualize their surroundings, and so never form memories of their locations (Siddique, 2013).

Place cells located in the hippocampus of the brain help form mental maps of your location.
[Photo: Hippocampus from Anatomography, Life Science Databases, License: CC BY-SA 2.1 JP]

Scientists are still not sure what causes DTD; even the concept of human navigation is still not thoroughly understood. Previous models involved placing rats into mazes to see if they could remember how to navigate their way to reach food at the other end (Green and Cook, 1997). From these experiments, researchers were able to determine that for each specific area in the maze, a “place cell” in the hippocampus of the brain would be activated. Each “place cell” would help the rat determine where it was and what direction it would need to head in next.

Neuroscientists Dr. Nachum Ulanovsky and his student, Dr. Michael Yartsev, of the Weizmann Institute were not satisfied. They realized that rat models only dealt with movement in a two-dimensional space, yet, humans do much more than run in straight lines; they move in a three-dimensional space.

In order to update the model for spatial navigation, scientists are beginning to study the brains of our furry mammalian friends: bats. Bats move three dimensions: right or left, forward or back, and also up or down. Bats are best known for their ability to navigate using a series of sound waves, also known as echolocation.

Bats are famous for their ability to navigate using sound waves, also known as echolocation.
[Edited Photo: Bats by ASU – Ask a Biologist, License: CC BY-SA 3.0]

Echolocation has its limitations, though; since these waves cannot travel farther than a few meters, bats need to rely on their spatial memories to properly move about. In a study conducted by Stanford researcher Jonathan R. Barchi, big brown bats, Eptesicus fuscus, were released into a dark room with hanging chains multiple times over the course of a week (Barchi, 2012). On the first day, Barchi noted that the bats seemed to rely heavily on echolocation to navigate. By the end of the week, the bats used echolocation far less and seemed to follow the same path through the room each time. Even when released from various points in the room, the bats still followed the same flight path. A month later, Barchi took the same bats and placed them in the room again. Despite having not been in the room for a period of time, the bats still remembered the obstacles and used the same, original flight path. These results suggest that bats are able to take a single scene of their environment and take a snapshot of it, creating a unique flight path that they continue to rely upon. Further research into how the bats do this, neurologically, can open the doors to finding a cure for DTD.

Big brown bats, such as these, are helping scientists learn more about spatial memory and DTD.
[Photo: “Big Brown Bat (Eptesicus fuscus), in Flight at Night, Rogue River National Forest, Oregon” by Angell Williams, License: CC BY 2.0]

Patients with Developmental Topographic Disorientation wake up every day only to face a strange, seemingly new world. Tasks that many of us do without even thinking are constant battles. Now, new studies using bats shine a ray of hope for those with this condition. Perhaps by studying more about bats’ incredible spatial memories, we can harness their secrets to navigation and find a cure for Ms. Roseman and many like her.

Works Cited

In Brief:

Developmental Topographic Disorientation (DTD) is a mental condition with no known cause or cure that stops people from forming mental maps of their surroundings.
People with DTD are unable to remember how to move to and from places, even those as familiar as their own homes.
Recent studies involving bats’ ability to form long-term spatial memories of specific environments offer a new way to learn more about the causes of DTD.

This article was written by cYw22. As always, before leaving a response to this article please view our Rules of Conduct. Thanks! -cYw Editorial Staff

Author: cYw22

Hi there, I’m another one of the student writers over here at the cYw blog! Thank you for stopping by and letting us share our stories with you! I find that scientific research is often moving at such a fast pace that we are not always able to keep up with everything. But that’s what I find so fabulous about cYw: it offers both its readers and writers the opportunity to sit back for a few minutes, get exposed to different things, and then hopefully understand a bit more of our world. Personally, just seeing all of amazing ways animals have helped scientists has solidified my love of our furry friends and my fascination for research. When I’m not busy writing for cYw, though, I can usually be found rereading my worn Harry Potter books or munching on some dark chocolate. So stay for awhile, read some articles, and learn something new! I hope you enjoy your time here!

11 Comments

Kathleen
June 6, 2014
Fascinating article – thank you! I’m always lost – this helps to explain why. Kathleen
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- cYw22
  June 15, 2014
  I’m glad you enjoyed it! I get lost extremely easily too (one of my earliest memories is of being lost in a department store!) so it was really interesting to learn more about how our brain deals with directions and navigation.
  Post a Reply
Kathleen
June 6, 2014
fascinating article – and very clearly put – thank you! As a person who is always lost in space, this gives me at least a possible reason why – DTD.
Post a Reply
- cYw22
  June 15, 2014
  Thank you so much for reading! I can definitely relate on constantly being lost – I always seem to “zone out” only to look up and realize I have no idea where I am! Hopefully, as researchers learn more about DTD and the way our brains navigate, we can find ways to gain a better sense of direction.
  Post a Reply
Nicole Duffee
June 6, 2014
Dear Cyw22,
Thank you for the article drawing attention to a condition that is little known. Most important, you make us ponder, and appreciate, the many activities the brain coordinates every day without our having to think them through. I applaud you for highlighting the exploration of brain function through animal models.
Post a Reply
- cYw22
  June 15, 2014
  Thank you so much for your kind comment! I’m so glad I got to share some of my newfound knowledge about this rather unknown condition! To be honest, before I first started researching, I had never even heard of DTD, so it was a very enjoyable and educating experience to learn more about the condition and about our brain in general. I definitely don’t take the many functions our brain intuitively fulfills for granted anymore! In general, the whole experience of researching and writing has made me extremely excited about the future of neurology and all the incredible discoveries there are still to make.
  Post a Reply
Sedra Schiffman
June 9, 2014
Much as I am terrified of bats, I was fascinated by what we can learn from these amazing creatures. And I certainly applaud their finely honed senses of direction, a gift I am not blessed with. As always, I find these cYw articles informative, easy to digest and always leaving me with a thirst for more knowledge.
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- cYw22
  June 15, 2014
  Bats are certainly not the fuzziest or most cuddle of creatures! Still, I can’t help but admire their amazing echolocation and all the knowledge they have given us. Thank you for reading and for your kind comment; it’s very excited to share my findings on these incredible animals!
  Post a Reply
Cecilia
June 16, 2014
Great article, I have just one comment.
The bats in the picture at the top of the article are little red flying foxes (Pteropus scapulatus), which, unlike the big brown bats in Barchi et al. study, do not use echolocation to navigate. Fruit bats, or flying foxes, use sight and smell to locate their food–fruit, nectar, and pollen.
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- cYw22
  June 16, 2014
  Thanks for your insight, I didn’t realize that before! I suppose it just goes to show that there is an extraordinarily amount of diversity, even among similar creatures, in modes of survival. Strangely enough, though, it seems that navigation sparks a common thread between certain fruit bats (namely the Egyptian fruit bat) and other insect-eating ones. Dr. Ulanovsky and Dr. Yartsev of the Weizmann Institute (mentioned briefly within the article) experimented with Egyptian fruit bats, only to realize that they rely on “place cells” to form mental maps of their surroundings in the same way that big brown bats do. However, it’s important to note that this specific species does use echolocation, unlike the majority of fruit bats, as you mentioned. It would be fascinating, though, to see how non-echolocation-using bats deal with navigation and whether that matches the methods of their echolocation-using cousins.
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H Gale
September 4, 2014
Numerous reports by owners of blind dogs indicated that their dogs were mapping based on sounds and echoes, plus scents. // thanks for a near report.
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