Featured Research

from universities, journals, and other organizations

Neuroscience of instinct: How animals overcome fear to obtain food

Date:
November 30, 2010
Source:
University of Washington
Summary:
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.

Pictured is a LEGO Mindstorms robot programmed to simulate predatory attack on a rat seeking food in a semi-naturalistic environment. The findings demonstrate that without the functioning amygdala and consequently devoid of fear, the animal's foraging behavior becomes perilously maladaptive, whereas an overactive amygdala hinders foraging decision even under safe circumstances.
Credit: Image courtesy of June-Seek Choi and Jeansok Kim.

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.

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. 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. 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.

Videos are available at: http://faculty.washington.edu/jeansokk/Robogator.html


Story Source:

The above story is based on materials provided by University of Washington. Note: Materials may be edited for content and length.


Journal Reference:

  1. June-Seek Choi and, Jeansok J. Kim. Amygdala regulates risk of predation in rats foraging in a dynamic fear environment. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.1010079108

Cite This Page:

University of Washington. "Neuroscience of instinct: How animals overcome fear to obtain food." ScienceDaily. ScienceDaily, 30 November 2010. <www.sciencedaily.com/releases/2010/11/101129152435.htm>.
University of Washington. (2010, November 30). Neuroscience of instinct: How animals overcome fear to obtain food. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2010/11/101129152435.htm
University of Washington. "Neuroscience of instinct: How animals overcome fear to obtain food." ScienceDaily. www.sciencedaily.com/releases/2010/11/101129152435.htm (accessed July 22, 2014).

Share This




More Plants & Animals News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

San Diego Zoo Welcomes New, Rare Rhino Calf

San Diego Zoo Welcomes New, Rare Rhino Calf

Reuters - US Online Video (July 21, 2014) An endangered black rhino baby is the newest resident at the San Diego Zoo. Sasha Salama reports. Video provided by Reuters
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com
A Centuries' Old British Tradition Is Far from a Swan Song

A Centuries' Old British Tradition Is Far from a Swan Song

AFP (July 19, 2014) As if it weren't enough that the Queen is the Sovereign of the UK and 15 other Commonwealth realms, she is also the owner of all Britain's unmarked swans. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins