To a neuroscientist like me, the inner workings of our emotional brains seem as mysterious as the inner workings of a black hole must have been to an astrophysicist like the father. my great. However, people seem to think they understand emotions because, unlike black holes, we experience them in our everyday lives. This discrepancy between what we actually know and what we think we know, emotionally has led to considerable confusion and heated debate.
Some prominent brain researchers have argued that “emotions” are something that can only be studied in humans but not in animals. For those of us pet owners, this position may seem absurd. Is it obvious that our dogs and cats, including my cats, have feelings? It is possible, but intuition is not enough. We have to look for proof, because animals are not little people in feathers and we can be fooled.
We often attribute emotions to an animal that we can identify. If a squirrel in Central Park freezes or runs away from me, it must be scared – because I would feel scared if I met an animal 12 times taller than me. However, without access to the animal’s inner life, how can we be sure that it is not merely exhibiting an automatic reflex? If a fruit fly freezes or jumps away from us, is it “afraid?” If it’s just a reflex, why isn’t the same for the squirrel?
The temptation to project our emotions onto other species is strong, especially other mammals. The monkeys playing with each other must be very excited. An elephant’s eyes leak fluid when a loved one dies; We infer it is sad. Our dogs roll on their backs with their paws in the air; We concluded that they were happy to see us. A whale singing on the ocean floor sounds lonely, and a lion roaring after being killed must feel “victory”.
But we are even willing to attribute emotions to animals that are not like us. A captive octopus that changes color when kids touch its tank makes us believe it’s showing irritation. But it could simply be reflexively trying to match its skin tone with the blinking reflexes of visitors. Furthermore, if we assert that the octopus has emotions, why shouldn’t its mollusk cousins do the same? When a sea scallop encounters a predatory starfish, it quickly opens and closes its shells as it tumbles to safety; Is that panic? We often call bees that spill from their hive to attack an intruder “angry.” If so, are the fighting fruit flies (yes, even male fruit flies fighting with females) “angry?” Or are all these diverse creatures just performing automatic survival behaviors, fixed in their brains by a series of evolutionary processes? This is not just an academic matter. Animal responses can provide much-needed support for human mental health research. Due to our lack of understanding of how the brain controls emotions, there has been virtually no fundamentally new drug to treat mental illness in the past 50 years. Indeed, most of the pharmaceutical and biotech companies gave up the search after costly failures.
Current treatments for serious mental illness such as depression, schizophrenia, or bipolar disorder are inadequate—and those treatments often have damaging side effects, possibly due to most Most such drugs just flood the brain with chemicals like serotonin or dopamine. It’s like changing your car’s oil by opening the hood and pouring a can of oil all over the engine, hoping that some of the oil will get in the right place. Maybe so, but a lot of it will seep into places where it does more harm than good.
“Even fruit flies can display an emotional state in their fleeing behavior when repeatedly exposed to a passing shadow.”
Human research into mental and emotional health often relies on brain scans. But such studies can only identify correlation, not cause and effect. To do that, we need to penetrate and regulate the brain, its neurons and its circuits. For ethical reasons, this cannot be done in human subjects; We need well-controlled neuroscience studies of emotion in laboratory animals. That means we need to determine if a certain animal’s behavior is emotional or just an adaptive reflex.
My Caltech colleague Ralph Adolphs and I argued that to study emotions in animals we should go beyond “feeling,” because animals cannot communicate that emotion to us. Conscious emotions in humans are just the tip of the brain’s emotional iceberg; there is a giant unconscious part below the surface that we share with many other living things. The subsurface is concerned with internal states of the brain, or characteristic patterns of electrical and chemical activity. These brain states, the building blocks of emotions, are represented by behaviors that have telltale cues that distinguish them from reflexes.
One of such building blocks is “scalability”. Emotional behaviors often escalate in intensity, from threatening attacks or from sniffling to sobbing. In contrast, reflexes tend to be all-or-nothing. Another feature is “persistence”. Emotional behaviors tend to last long after their euphoric stimulus wears off, whereas reflexes cease quickly. And unlike reflexes, inner emotional states exhibit “generalization”. A bad day at the office for humans affects how you respond to a screaming child at home, and animals have their equivalents.
Recent research has revealed evidence of these emotional states in the “fight-or-flight” response in both rats and fruit flies. For example, rats with short-term exposure to natural predators exhibit persistent open space avoidance for several minutes, indicating persistence. Furthermore, their reactions escalate from dodging to freezing to running and jumping as enemies approach. Male rats exposed to predators would delay resumption of mating or interrupted feeding until some time has elapsed, indicating generalization. These indicators collectively suggest that the response to a predator is not simply a reflex, but is more likely a manifestation of a state of defensive arousal or threat warning within the brain.
Even fruit flies can display an emotional state in their fleeing behavior when exposed to repeated exposure to a passing black shadow overhead (mimicking an approaching aerial predator). If the flies are enclosed in a transparent arena so that they cannot fly away, their response will escalate with each successive ballooning, from interrupted feeding, to running around the perimeter of the arena and jumping. like popcorn. These reactions persist for several minutes after the shade ends, as the flies gradually “calm down” and return to their food. These little insects act a lot like birds scattering into the trees when you get close to their feeder, and they gradually return to their food only after a while, when the danger has passed. Go.
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Once we have identified emotional behaviors in a given species, we can use powerful new neuroscientific methods to understand how they are generated. In one such method, known as photogenetics, specific populations of neurons are genetically engineered to activate proteins that convert light into electricity. The neurons can then be activated or inhibited at the click of a switch that transmits light pulses through microscopic optical fibers inserted into the brain. Using such methods, my lab and others have discovered that small groups of neurons in an area of the brain called the hypothalamus control the strength and length of fear states. fear or aggression in rats. Optical genetics cannot yet be performed in humans, for technical reasons and because the long-term safety of the necessary gene edits is unknown.
If we better understand the nerve cells, electrical circuits, and chemistry that control our inner emotional states, we could eventually develop new drugs or brain-stimulating therapies that are specific to these emotional states. those nerve cells. In effect, such a treatment would be like pouring oil into the part of the engine where it belongs. We need to study emotions in animals to get there.
—P. Anderson, a biology professor at the California Institute of Technology, is the author of “The Nature of the Beast: How Our Emotions Guide Us” (The Basics), from which this essay was adapted.
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https://www.wsj.com/articles/what-can-animals-tell-us-about-emotions-11647610371 What Can Animals Tell Us About Emotions?