Fran Laurendeau / RooM RF / photographic imaging
We humans often say that a howling dog is “angry” or that a grumbling cat is “happy”.
But those words are not used by scientists like David Anderson, a biologist at Caltech who teaches motor vehicles about different concepts. “We have to do other things than put our own opinions on other animals,” he says, “because small animals don’t have fur coats. “
Animals cannot tell us what they think. But Anderson believes there is a connection between animals and human emotions.
“Thoughts are the actions of the brain that develop over time in a natural selection,” he says. “They weren’t just seen in the world since the advent of Homo sapiens. “
That idea is central to Anderson’s new book, The nature of the beast: How thoughts guide us. It is critical that the growth of science seeks new treatments for diseases such as PTSD by manipulating the brain -related brain cells in animals.
In his book, Anderson describes research from his lab showing that the brain circuits under the human senses are much the same as the circuits found in rats and mice.
Thoughts and opinions
To study emotions in animals, Anderson says scientists first need to separate their own emotions from normal human emotions such as anger, fear, sadness and happiness.
That is, they have to look before the man opinion.
“That part of the mind is the tip of the iceberg, above the sea of our knowledge,” Anderson said. “The piece below is what we share like the animals.”
The bottom line, he says, is that the states of the brain act in certain ways. And that is the part of the idea that scientists can learn. For example, Anderson’s lab researched that butterflies are stronger when they see a moving shadow similar to that thrown by a flying squirrel.
“We see the more times we give the shadow, the more the flies fly, and the more they actually fly like popcorn,” he said.
And the flies always fly after the shadow is gone.
Anderson would do the same if he walked by and saw the snake rattles.
“I’ll fly in the air,” he said. “But even a few minutes after the snake fled into the forest, my heart would pound, my mouth would dry up or I would jump every time I saw something like a snake. in front of me – if it were a tree.. “
This type of brain disorder is usually called defensive arousal. It is in the eggs and humans, which is why Anderson believes that capturing fear in the disappearance or the mouse can express a lot of human emotions.
“We can try to think about how the brain works in that state and what lasts longer and what rests the animal,” Anderson said.
In the rat, the response was found to be that specific brains become hyperactive when the rat perceives a threat and slowly returns to normal after the threat has passed. Anderson believes that a diverse group of people instills the idea that we know we are afraid.
Anger between types
Any human thought that may have its roots in the animal concept of anger.
There’s no way to know if animals have angry feelings, says Dayu Lin, a neuroscientist at New York University. This type of cruelty can be seen in human anger in fish, reptiles, birds and mammals.
So Lin is learning the parts of the brain that deal with anger. And he’s got something serious.
“There’s a little bit of space in the brain, and we all have it,” he said.
In humans, this region is near the bottom of the hypothalamus, just above the pituitary gland. And studies in mice and other animals show that this cluster of brain cells is part of the critical aggression cycle.
“We can arouse the anger by infecting this area with rodents,” Lin said.
Turn on and load the mouse. Destroy him and the animal’s natural rage disappears. There is some evidence that this can happen to humans. Doctors sometimes use deep brain stimulation to end the aggression cycle in the most severe psychiatric patients.
“Normally anger can’t be controlled,” Lin said. “That’s the last thing you want.”
Trauma, fear and PTSD
Animal concepts are also helping scientists understand certain psychiatric disorders, including post-traumatic stress disorder (PTSD).
“We really see PTSD as a progressive disorder, the critical anxiety response has gone a long way,” said Dr. Kerry Ressler of Harvard Medical School and McLean Hospital.
For a person with PTSD, a small event can produce a stress and fear response that lasts for hours, Ressler said. And there is a similarity of animals.
The normal mouse would dry up when it heard a sound about an electric shock. But when the shaking is over, the animal immediately learns to let go of the sound.
Trauma changes that kind of learning.
“If they get hurt more than the animal, they’ll learn quickly, they’ll dry up for a long, long time to quench or learn that voice is really safe,” Ressler said.
In both humans and rats, trauma is seen to alter a brain circuit surrounding the amygdala and prefrontal cortex. And in rodents, that cycle can be fixed.
“We now see specific parts of the circle that increase fear and other parts of the circle that reduce fear,” or the animal nature of that idea, Ressler said.
The next step, he says, is to consider how to change that cycle to reduce the fear response in people with PTSD.