September 12, 2011
Study: Humans Are Wired To Respond To Animals
Researchers from the California Institute of Technology (Caltech) found in a new study that an area of your brain is hard-wired to respond to animals, whether they are cute and fluffy or ugly and threatening.
No matter what your response is to animals, it could be thanks to that specific area of the brain that is hard-wired to rapidly detect other creatures. Working with researchers from UCLA, Caltech researchers report that neurons throughout the amygdala -- a center in the brain known for processing emotional reactions, fear and sense of smell -- respond preferentially to images of animals.
The researchers showed images of people, places, animals and objects to 41 recruited epilepsy patients, who were already wired up so other doctors could monitor their brain activity related to seizures, from the Ronald Reagan UCLA Medical Center. The team recorded single-neuron responses in the amygdala when the patients viewed the images.
“Our study shows that neurons in the human amygdala respond preferentially to pictures of animals, meaning that we saw the most amount of activity in cells when the patients looked at cats or snakes versus buildings or people,” said Florian Mormann, lead study researcher and a former postdoctoral scholar at Caltech.
“This preference extends to cute as well as ugly or dangerous animals and appears to be independent of the emotional contents of the pictures. Remarkably, we find this response behavior only in the right and not in the left amygdala,” Mormann said.
The team found that activity in the right amygdala was not only greater, but neural responses were also faster for the animal pictures. They then found the same response among people not suffering from epilepsy.
Team leader Ralph Adolphs said that past research of the amygdala focused on faces and fear, so it was a surprise to see that neurons in the right amygdala responded more to animals than to human faces.
“I think this has the potential to help us better understand phobias of animals,” Adolphs tolf The Mail Online.
Mormann said the results indicate that the brain´s right hemisphere evolved to deal with unexpected and biologically relevant stimuli. “In terms of brain evolution, the amygdala is a very old structure, and throughout our biological history, animals - which could represent either predators or prey - were a highly relevant class of stimuli,” said Mormann.
“This is a pretty novel finding, since most amygdala research in the past was usually about faces of people and emotions related to fear rather than pictures of animals,” added Adolphs. “Nobody would have guessed that cells in the amygdala respond more to animals than they do to human faces, and in particular that they respond to all kinds of animals, not just dangerous ones. I think this will stimulate more research and has the potential to help us better understand phobias of animals.”
The study also shows a clear picture of how scientists doing basic research can benefit from working with collaborators in a clinical setting and vice versa.
“This is a good example of how special situations in neurosurgery–in this case, patients who are treated in order to cure their epilepsy–can provide a unique window into the workings of the human mind,” said study coauthor Itzhak Fried, a UCLA neurosurgeon.
The research appeared online August 28 in the journal Nature Neuroscience.
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