Tag Archives: brains

How ants navigate homeward – forward, backward, or sideward

I’ve got this press release that will be of interest to many:

An international team including researchers at the university of Edinburgh and Antoine Wystrach of the Research Centre on Animal Cognition (CNRS/Université Toulouse III—Paul Sabatier) has shown that ants can get their bearings whatever the orientation of their body. Their brains may be smaller than the head of a pin, but ants are excellent navigators that use celestial and terrestrial cues to memorize their paths. To do so, they use several regions of the brain simultaneously, proving once again that the brain of insects is more complex than thought. The researchers’ findings were published in Current Biology on January 19, 2017.

Until now, ethological research suggested that ants memorized the scenery perceived along their route as it is projected on their multifaceted retinas—thus using a body-centered, or egocentric, frame of reference. By this hypothesis, to recognize memorized surroundings and follow a path formerly traveled, ants would need to orient their bodies in the same way each time. But they sometimes need to walk backwards as well, and this doesn’t prevent them from finding their way back to their nest. Could it be that ants can recognize a route when facing the opposite direction? Are they able to create a visual model of their environment that is independent of their body orientation?

To answer these questions, the researchers studied Cataglyphis velox, an Andalusian desert ant known for its solo navigation ability. First they let the insects familiarize themselves with a route that included a 90° turn. After a day of training, ants that received a cookie crumb light enough to carry while walking forward handled the turn without the slightest difficulty. However, those given large cookie crumbs had to move backward, and unlike the others, they maintained their bearing instead of turning.

They also exhibited unexpected behavior: After walking backward a bit, they would occasionally drop their crumb, turn around, observe the scenery while pointing their bodies in the right direction, return to the crumb, and resume towing it backward – but this time in the correct direction. For these ants, body alignment thus seems necessary for recognition of scenery perceived by their retinas, but they are then able to memorize the new bearing and follow it backward. This behavior also shows that they can recall the existence of the dropped cookie crumb, and its location, in order to return to it after updating their bearing. These observations imply that at least 3 kinds of memory are working in unison: the visual memory of the route, the memory of the new direction to follow, and the memory of the crumb to retrieve.

Through another experiment using a mirror to reflect the sun1, the team demonstrated that the ants used celestial cues to maintain their bearing while walking backwards. Furthermore, ants were able to move in straight paths, whether walking forward, backward, or sideways. Once a bearing is memorized, they stay on it no matter how their bodies are oriented. Together these observations suggest that ants register direction using an external – or allocentric – frame of reference.

These new findings show that the ants’ spatial orientation relies on multiple mental representations and memories woven together through a flow of information between several areas of their brain. This offers a whole new perspective on the world of insects, which is much more complex than previously believed.

The Brain: An Illustrated History of Neuroscience

In 1817, Karl August Weinhold had a go at a real-life Frankenstein’s monster — only in his version he uses a cat. The German scooped out the brain and spinal cord of a recently dead cat. He then pured a molten mixture of zinc and silver into the skull and spinal cavity. He was attempting to make the two metals work like an electric pile, or battery, inside the unfortunate cate, replacing the electrical of the nerves. Weinhold reported that the cat was revived momentarily by the currents and stood up and stretched in a rather robotic fashion!

It’s Alive!!!!

Weinhold’s reanimated cat was just the tip of the iceberg. In those days, the same days during which Mary Shelley wrote Frankenstein, the forerunners of modern neuroscience were reanimating all sorts of animals (it started, of course, with frogs) including humans, with suitably horrifying results, using primitive electricity generating machines and ingeniously placed probes.

Screen Shot 2015-11-19 at 12.00.49 PMThe Brain: An Illustrated History of Neuroscience (Ponderables 100 Ideas That Changed Histoy Who Did What When) (Ponderables 100 Discoveries That Changed Histoy Who Did What When) by the prolific Tom Jackson (see list below) mentions the cat story in a small sidebar, but several of the 100 moments in neuroscience relate to this sort of early scientific activity. The idea of the book is to put a large topic, in this case the history of neuroscience, into 100 bite sized pieces (with a 101st item at the end, a sort of technical summary) in chronological order. The result is a very browsable and fascinating book, an educational and entertaining coffee table item, even a good gift idea.

I know something about neuroscience and brain evolution, and even a bit about the history of this research, and I found most of the entries to be reasonable, well researched, and accurate. There is sufficient debunking of some of the bad ideas (about race, IQ, etc.), though I would like to have seen Jackson’s treatment of lateralization to have been a bit more probing and nuanced, since that is one of the areas where pop culture has overstayed its welcome. Still, the book is scientifically accurate, not to deep yet not a gloss.

One of the neat features of the book is a giant pull out unfoldable wall poster that is a timeline of the history of neuroscience. I’ll probably give that to my wife for her to hang in her biology classroom, especially since she teaches a fair amount about brains and intends to expand on that teaching over the next couple of years.

The other side of the foldout timeline is a set of optical illusions, including the blind spot test, the arrows affecting the apparent length of the line test, and a lot of the other usual illusions, all very well done with quality presentation and printing.

There are bits at the beginning and end of the book (including item 101, mentioned above) that serve as reference material. There is an index, though it is not dense (for example, having noted the cat story I use above, I tried to look it up in the Index but couldn’t find it). Also as an appendix is a explication of several key open questions in neurobiology (the “Imponderables”). Also, references are supplied.

The illustrations are excellent throughout.

This book is for anyone interested in science, especially neuro. If you cover this topic in your High School or Middle School classes, it is a good book to have in your library. It would make an excellent gift for the science-oriented person you know, especially since it is just out and they won’t have it yet.

This is part of the Ponderables series of illustrated books published by Shelter Harbor Press.

Other books by Tom Jackson:

<li><a rel="nofollow" href="http://www.amazon.com/gp/product/0985323043/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0985323043&linkCode=as2&tag=grlasbl0a-20&linkId=WAJHFL4LOZ2AB3YD">Mathematics An Illustrated History of Numbers (100 Ponderables)</a><img src="http://ir-na.amazon-adsystem.com/e/ir?t=grlasbl0a-20&l=as2&o=1&a=0985323043" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" /></li>

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Dawkins…. On Purpose

Dawkins gave a talk that could be criticized as not particularly new, in that his main idea is that human brains are too powerful and adaptable to continue to function primarily within an adaptive program serving as a proper adaptive organ. Instead, human brains think up all sorts of other, rather non-Darwinian things to do. This idea has been explored and talked about in many ways by many people. Kurt Vonegut Jr.’s character in Galapagos repeatedly, in a state of lament, quips “Thanks, Big Brain…” as evidence accumulates that our inevitable march towards extinction is primarily a function of that particular organ’s activities. People have talked about the brain as the outcome of runaway sexual selection. Evolutionary psychologists have talked about the evolution of strong preferences and desires, which in turn play out i a rather Frankensteinian fashion in a world where those desires can be met with ease instead of hard work and much time. Thus, we have evolved a yearning for rare nutrients such as salt and fat, and then we invented the ability to have unlimited access to salt and fat. So now, in a ‘civilized world’, it is the salt and fat that kills us incited of the predator or the con-specific competitor over access to some food or some sexual opportunity. (Thanks, Big Brain….)
Continue reading Dawkins…. On Purpose

Male vs. Female Brains

The male and female human brains are different. Some of the better documented differences are similar to differences seen in other mammals. They are hard to find, very small, and may or may not be of great significance. Obviously, some are very important because they probably relate to such things as the ability … or lack thereof … to bear offspring. But this is hardly ever considered in the parodies we see of these differences.

[Repost from Gregladen.com]
Continue reading Male vs. Female Brains