Study finds analysis of many species required to better understand the brain

April 29, 2013
A big brown bat, Eptesicus fuscus, flying in the University of MarylandÂ’s Auditory Neuroethology laboratory. Credit: Jessica Nelson, University of Maryland

To get a clear picture of how humans and other mammals form memories and find their way through their surroundings, neuroscientists must pay more attention to a broad range of animals rather than focus on a single model species, say two University of Maryland (UMD) researchers, Katrina MacLeod and Cynthia Moss. Their new comparative study of bats and rats reports differences between the species that suggest the need to revise models of spatial navigation.

In a paper appearing in the April 19, 2013 issue of Science, the UMD researchers and two colleagues at Boston University reported significant differences between rats' and bats' when certain cells were active in a part of the brain used in memory and navigation.

These cells behaved as expected in rats, which mostly move along surfaces. But in bats, which fly, the continuous brain rhythm did not appear, said Moss, a professor in Psychology and the Institute for Systems Research.

The finding suggests that even though rats, bats, humans and other mammals share a common of space in a part of the brain that has been linked to spatial information and memory, they may have different to create or interpret those maps, said MacLeod, an assistant research scientist in Biology.

"To understand brains, including ours, we really must study in a variety of animals," MacLeod said. "Common features across multiple species tell us 'Aha, this is important,' but differences can occur because of variances in the animals' ecology, behavior, or ."

The research team focused on a brain region that contains specialized "," so named because they form a hexagonal grid of activity related to the animal's location as it navigates through space. This brain region, the medial entorhinal cortex, sits next to the hippocampus, the place that, in humans, forms memories of events such as where a car is parked. The medial entorhinal cortex acts as a hub of neural networks for memory and navigation.

Grid cells were first noticed in rats navigating their environment, but recent work by Nachum Ulanovsky (Moss's former postdoctoral researcher at UMD) and his research team at the Weizmann Institute in Rehovot, Israel, has shown these cells exist in bats as well.

In rats, grid cells fire in a pattern called a theta wave when the animals spatially navigate. Theta waves are fairly low-frequency electrical oscillations that also have been observed at the cellular level in the medial . The prominence of theta waves in rats suggested they were important. As a result, neuroscientists, trying to understand the relationship between theta waves and grid cells, have developed models of the brain based on the assumption that theta waves are key to spatial navigation in mammals.

However, Moss said, "recordings from the brains of bats navigating in space contain a surprise, because the expected theta rhythms aren't continuously present as they are in the rodent."

The new Science study doubles down on the lack of theta in bats by reporting that theta rhythms also are not present at the cellular level. "The bat neurons don't 'ring' the way the rat neurons do," says MacLeod. "This raises a lots of questions as to whether theta rhythms are actually doing what the theory proposes in rats or even humans."

The article is titled "Bat and Rat Neurons Differ in Theta-Frequency Resonance Despite Similar Coding of Space."

Explore further: Rats' and bats' brains work differently on the move

More information: www.sciencemag.org/content/340/6130/363.abstract

Related Stories

Rats' and bats' brains work differently on the move

April 18, 2013
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 ...

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

April 28, 2011
In a paper to be published today in the journal Science, a team of Boston University researchers under the direction of Michael Hasselmo, professor of psychology and director of Boston University's Computational Neurophysiology ...

Fluctuations in size of brain waves contribute to information processing

February 8, 2013
Cyclical variations in the size of brain wave rhythms may participate in the encoding of information by the brain, according to a new study led by Colin Molter of the Neuroinformatics Japan Center, RIKEN Brain Science Institute.

Primates' brains make visual maps using triangular grids

October 28, 2012
Primates' brains see the world through triangular grids, according to a new study published online Sunday in the journal Nature.

GPS in the head? Rhythmic activity of neurons to code position in space

September 15, 2011
Prof. Dr. Motoharu Yoshida and colleagues from Boston University investigated how the rhythmic activity of nerve cells supports spatial navigation. The research scientists showed that cells in the entorhinal cortex, which ...

Recommended for you

Faulty support cells disrupt communication in brains of people with schizophrenia

July 20, 2017
New research has identified the culprit behind the wiring problems in the brains of people with schizophrenia. When researchers transplanted human brain cells generated from individuals diagnosed with childhood-onset schizophrenia ...

Scientists discover combined sensory map for heat, humidity in fly brain

July 20, 2017
Northwestern University neuroscientists now can visualize how fruit flies sense and process humidity and temperature together through a "sensory map" within their brains, according to new research.

Scientists reveal how patterns of brain activity direct specific body movements

July 20, 2017
New research by Columbia scientists offers fresh insight into how the brain tells the body to move, from simple behaviors like walking, to trained movements that may take years to master. The discovery in mice advances knowledge ...

Team traces masculinization in mice to estrogen receptor in inhibitory neurons

July 20, 2017
Researchers at Cold Spring Harbor Laboratory (CSHL) have opened a black box in the brain whose contents explain one of the remarkable yet mysterious facts of life.

Speech language therapy delivered through the Internet leads to similar improvements as in-person treatment

July 20, 2017
Telerehabilitation helps healthcare professionals reach more patients in need, but some worry it doesn't offer the same quality of care as in-person treatment. This isn't the case, according to recent research by Baycrest.

New study reveals contrasts in how groups of neurons function during decision making

July 19, 2017
By training mice to perform a sound identification task in a virtual reality maze, researchers at Harvard Medical School and the Istituto Italiano di Tecnologia (IIT) have identified striking contrasts in how groups of neurons ...

0 comments

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.