Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Neuroscience of instinct: How animals overcome fear to obtain food

30.11.2010
When crossing a street, we look to the left and right for cars and stay put on the sidewalk if we see a car close enough and traveling fast enough to hit us before we're able to reach the other side. It's an almost automatic decision, as though we instinctively know how to keep ourselves safe.

Now neuroscientists have found that other animals are capable of making similar instinctive safety decisions. In a study published online the week of Nov. 29 in the Proceedings of the National Academy of Sciences, University of Washington researcher Jeansok Kim demonstrates that rats weigh their odds of safely retrieving food pellets placed at varying distances from a perceived predator.

"When animals go out to forage, they're taking a risk," said Kim, a UW psychology professor. "They're leaving the safety of their nests, venturing out where there may be predators that could eat them."

But staying in the nest is not a safe option either, rats need to get out and find food. How do they decide whether it's safe to leave the nest? Kim and co-author June-Seek Choi, a visiting professor in the UW psychology department from Korea University, studied how the amygdala – known to be an important brain area for perceiving and reacting to fear – was involved in the rats' decisions to risk their safety for food.

In humans, impaired amygdala activity has been linked to risky decision-making, such as gambling. And an overactive amygdala could explain anxiety disorders, including post-traumatic stress disorder and phobias.

Kim and Choi trained male rats to retrieve a food pellet placed at varying distances from a safety zone, or nest. The rats, hungry from a restricted food supply for several days, quickly learned to retrieve the food pellets. (To see a video of rats foraging, watch "Foraging baseline day 5": http://faculty.washington.edu/jeansokk/Robogator.html).

The researchers introduced a "predator," an alligator-shaped robot that was programmed to snap its jaws and surge at the rats. With a body made of gray LEGO blocks and fangs of bright orange LEGOS, the LEGO Mindstorms Robogator was about twice the size of the rats. The researchers programmed the robot to lurch forward about 9 inches, open and shut its mouth and then return to its resting spot far away from the rats' nest.

With the robot in place, the rats began foraging as usual. When they neared the food, the Robogator quickly moved toward the rats and snapped its jaws. The rats scurried back to the safety of the nest and then momentarily froze – a typical fear response.

Still hungry, the rats paced back in forth in the nest areas, hidden from the Robogator (see video "Robot encounter day 1: Pre-amygdalar lesion": http://faculty.washington.edu/jeansokk/Robogator.html). Slowly they re-emerged and cautiously approached the food, while the Robogator continued its aggressive movements whenever the rats neared the food pellet. Most rats learned that they could safely retrieve the food pellet placed closest, 10 inches, from their nest and not intersect the robot's path. None of the rats obtained the pellet nearer the Robogator, about 30 inches from the nest.

Kim compared the rats' decision-making process to the classic math problem that asks when two trains leaving at different times from different places and traveling at different speeds will pass each other. With a predator nearby, Kim said, rats gauge how quickly they can run to the food, how quickly the predator moves and how far away the pellet is from the rat and from the predator. If they judge that there's a chance the rat and robot will cross paths, they don't attempt to get the food.

"Like when people cross the street, we just tend to automatically have a sense of what is safe," Kim said. "I think that most animals have that capability in their nervous system. Through our amygdala, we instinctively know what keeps us safe."

Overactive amygdala could explain anxiety disorders and irrational fears in humans, Kim said. Brain imaging studies show heightened amygdala activity in patients with post-traumatic stress disorder. Underactive amygdala could be linked to risk-taking and impulsive behaviors.

To study this in rats, the researchers created amygdala lesions and observed the rats' subsequent interactions with the robot. Rats with lesions were unperturbed by the Robogator, and when food was placed near the predator the rats ran straight for the food, barely flinching when the Robogator lunged and snapped (see video "Robot encounter day 2: Post-amygdalar lesion": http://faculty.washington.edu/jeansokk/Robogator.html). The same was true when the researchers inactivated the amygdala with the chemical muscimol.

When Kim and Choi increased the amygdala activity, the rats showed greater fear. Even when the food was at a safe distance from the robot, rats treated with the drug bicuculline, which increases neural activity, were too afraid to venture out for the pellet.

"Because humans share many biological and behavioral features with animals, experimental studies with rats provide valuable information toward understanding the physiological as well as the psychological aspects of fear," Kim said.

The study was funded by the National Institutes of Health, the National Research Foundation of Korea Grant, the Ministry of Education, Science and Technology and the Seoul Broadcasting System Foundation.

For more information, contact Kim at 206-616-2685 or jeansokk@uw.edu.

Molly McElroy | EurekAlert!
Further information:
http://www.uw.edu

More articles from Life Sciences:

nachricht Researchers target protein that protects bacteria's DNA 'recipes'
21.08.2018 | University of Rochester

nachricht Protein interaction helps Yersinia cause disease
21.08.2018 | Schwedischer Forschungsrat - The Swedish Research Council

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Air pollution leads to cardiovascular diseases

21.08.2018 | Ecology, The Environment and Conservation

Researchers target protein that protects bacteria's DNA 'recipes'

21.08.2018 | Life Sciences

A paper battery powered by bacteria

21.08.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>