Rats' and bats' brains work differently on the move

April 18, 2013
Flying animals, like this big brown bat in Prof. Cynthia Moss' laboratory, may navigate differently than ground-dwelling rodents. Comparative studies are needed as neuroscientists develop models of how the brain processes spatial information, Moss says. Credit: Jessica Nelson

A new study of brain rhythms in bats and rats challenges a widely used model - based on studies in rodents - of how animals navigate their environment. To get a clearer picture of the processes at work in the mammal brain during spatial navigation, neuroscientists must closely study a broad range of animals, say the two University of Maryland College Park scientists involved in the study.

In the April 19, 2013 issue of Science, the University of Maryland researchers and two colleagues at Boston University reported significant differences between rats' and bats' in a part of the brain used in navigation.

The researchers focused on specialized cells that process spatial information in a region called the medial entorhinal cortex, a hub of neural networks for memory and navigation. Earlier experiments showed rats' in this area fire continuously in a rhythmic electrical signal called a theta wave when the animals are navigating through space. Some models of the brain treat theta waves as a key element of in all mammals, but this idea is based on rodent research, Moss said.

The Boston University-University of Maryland team tested for rhythmic electrical responses at the cellular level in bat and rat brain tissue. They found evidence for theta waves in the rat cells. But in the bat cells these waves were absent, said Moss, who has studied bats since the 1980s.

"This raises questions as to whether theta rhythms are actually doing what the spatial navigation theory proposes," said a co-author, UMD biology researcher Katrina MacLeod. "To understand brains, including ours, we really must study neural activity in a variety of animals."

Humans and other mammals share many common features of , and the differences in between bats and rats raises questions about how spatial information is represented in all brains.

Explore further: Researchers probe link between theta rhythm, ability of animals to track location

More information: "Bat and Rat Neurons Differ in Theta-Frequency Resonance Despite Similar Coding of Space," by J.G. Heys, K.M. MacLeod, C.F. Moss, and M.E. Hasselmo, Science, 2013.

See also: Neural activity in bats measured in-flight

Related Stories

Brain state affects memory recall

June 13, 2011

Lost your keys? Your brain might be in a better state to recall where you put them at some times than at others, according to new research from UC Davis. A paper describing the work is published June 13 in the journal Proceedings ...

Recommended for you

Umbilical cells help eye's neurons connect

November 24, 2015

Cells isolated from human umbilical cord tissue have been shown to produce molecules that help retinal neurons from the eyes of rats grow, connect and survive, according to Duke University researchers working with Janssen ...

Brain connections predict how well you can pay attention

November 24, 2015

During a 1959 television appearance, Jack Kerouac was asked how long it took him to write his novel On The Road. His response – three weeks – amazed the interviewer and ignited an enduring myth that the book was composed ...

No cable spaghetti in the brain

November 24, 2015

Our brain is a mysterious machine. Billions of nerve cells are connected such that they store information as efficiently as books are stored in a well-organized library. To this date, many details remain unclear, for instance ...

Neurons encoding hand shapes identified in human brain

November 23, 2015

Neural prosthetic devices, which include small electrode arrays implanted in the brain, can allow paralyzed patients to control the movement of a robotic limb, whether that limb is attached to the individual or not. In May ...

Wireless sensor enables study of traumatic brain injury

November 23, 2015

A new system that uses a wireless implant has been shown to record for the first time how brain tissue deforms when subjected to the kind of shock that causes blast-induced trauma commonly seen in combat veterans.


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Apr 18, 2013
Navigating in terrain is very different from navigating in flight.

The rat faces what is essentially a 2D maze, even if it can climb to other levels. It can observe and learn the maze at a more leisurely pace, and even stop whenever it "needs to think". (Which it actually does all the time!)

The bat can't stop in mid-flight to "think" or figure out the surroundings. Therefore its navigation has to be more "real-time" and fluid. And of course, the bat has to actively use sonar, instead of just seeing all obstacles and targets.

All this places very different, and much higher demands on the bat brain. No wonder it has developed some fundamentally different operating principles.
not rated yet Apr 19, 2013
Some species of bat (perhaps all using sonar) separate communicative and navigational calls into lower and higher octave bands respectively - hence perhaps their 'theta' rhythms likewise occupy higher registers..?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.