Wednesday, December 3, 2014

3-D compass in Egyptian fruit bat's brain

Egyptian fruit bat Rousettus aegyptiacusimage Wikimedia

Ruth Schuster reported 03/12/2014 in Haaretz about a fascinating brain research project going on in Weizmann Institute:

Israeli scientists have finally proved the existence of a three-dimensional compass in mammalian brains, with the help of the humble fruit bat.

Grad student Arseny Finkelstein and team demonstrated that the brain of the Egyptian fruit bat has special neurons that can tell which way its head is pointing. They could be key to the bat navigating in space, says the team in a study published today in Nature.

Vertigo such as that experienced by fighter pilots happens when this system goes haywire, their study suggests.

Navigation relies on spatial memory: past experience of different locations, they explain. That spatial memory is formed in a primitive brain structure in the hippocampus.

In the mammalian hippocampus, there are three types of brain cells key to navigation: “place” and “grid” cells, which like a biological GPS system, enable animals to keep track of their position - and “head-direction” cells. Those are the ones that act like a compass, responding when said beast turns its head.

Much work had been done on place and grid cells but practically none on the head-direction one. To change that, the researchers enlisted fruit bats with micro-electrodes implanted in their brains, to monitor their neuronal activity, and tracking devices that could tell when the bats moved their little heads.

Read the entire Haaretz science article.


Wildscreen ARKive has photos, videos and facts about the charming Egyptian fruit bat Rousettus aegyptiacus

Nature article preview  Arseny Finkelstein, Dori Derdikman, Alon Rubin, Jakob N. Foerster, Liora Las & Nachum Ulanovsky Three-dimensional head-direction coding in the bat brain

Monday, October 6, 2014

Nobel Prize for the brain's GPS discovery

image Wikimedia

BBC News website health editor James Gallagher reports October 5, 2014:
UK-based researcher Prof John O'Keefe as well as May-Britt Moser and Edvard Moser share the award. They discovered how the brain knows where we are and is able to navigate from one place to another. Their findings may help explain why Alzheimer's disease patients cannot recognise their surroundings.

Prof O'Keefe, from University College London, discovered the first part of the brain's internal positioning system in 1971. ... His work showed that a set of nerve cells became activated whenever a rat was in one location in a room. A different set of cells were active when the rat was in a different area. Prof O'Keefe argued these "place cells" - located in the hippocampus - formed a map within the brain.

In 2005, husband and wife team, May-Britt and Edvard, discovered a different part of the brain which acts more like a nautical chart. These "grid cells" are akin to lines of longitude and latitude, helping the brain to judge distance and navigate. They work at the Norwegian University of Science and Technology in Trondheim.
The Nobel committee said the combination of grid and place cells "constitutes a comprehensive positioning system, an inner GPS, in the brain". They added: "[This system is] affected in several brain disorders, including dementia and Alzheimer's disease.

"A better understanding of neural mechanisms underlying spatial memory is therefore important and the discoveries of place and grid cells have been a major leap forward to advance this endeavour."
Read the entire article from BBC News

Interesting, how advances in modern technology is helping scientists to define questions and use such basic concepts as grid map and GPS in their work!

As we know how devastating Alzheimer's disease is these discoveries about the amazing functionality of our brain have very practical consequences. It is also mapping major routes towards better understanding of the mapping capabilities of insects, fish, birds, land animals and humans our Creator has given to all living things in His great and deep wisdom.