To make love instead of war - it turns out that at the level of neural networks, this is true and possible. In fact, in mice, it is possible to activate a neural network of love-making during aggression, and it immediately stops the aggression. Yes, a specific neural network serves as a switch that we can turn on or off at will and cause mice to make love or war! What are we talking about?
Professor David Anderson, one of the world's leading brain scientists today, has published a series of articles in recent years in Science and Nature, the most prestigious scientific journals in the world. He discovered that in the brain - specifically in the hypothalamus - there are two regions: one region, when activated, causes a burst of violence, and another region - very close to it but different - when activated, causes a burst of mating (1).
In mice and other animals, during mating, the male mounts the female and begins a series of rhythmic movements. Sometimes the male mounts another male, which at first looks exactly like mating, but usually continues to fighting. Although the two behaviors initially appear the same, Dr. Anderson showed that when the male mounts another male, it is usually used to create dominance. Importantly, when the male mounts a female, he emits sounds at a frequency that we are unable to hear (in human terms, we would say that he groans or sings to her), but when he mounts another male, he does not make any sound. Thus, when a male mounts a female it is part of love-making but when it mounts another male it's violence for showing dominance.
To summarize, Dr. Anderson was able to characterize two groups of cells that are activated differently in love-making and war-making, and they inhibit each other.
Do really these cells, totaling something like 2,000 cells only - out of about hundred million in a mouse's brain - create the complex behavior of love or war?
Dr. Anderson guessed that they do, meaning that these cells make the switch between mating and aggression. To test this, he either activated or inhibited the activity of one network or the other. (To do this, he genetically engineered the mice so that he could activate a specific and precise network with a laser light). The results were sharp and clear as a butcher's knife: yes, that's exactly what happens.
Here is a video in which Dr. Anderson activated the neuronal network for mating in the hypothalamus, called MPOA (the main area for desire in the brain) of a male, and as a result, the male immediately began to try to mate with the male next to him in the cage: yup, by a switch of a button he began love-making with another male!
(If you're watching the video in the link, note the panel below it: in that panel you "see" the sounds that we can't hear. Before the laser is activated, there is no sound activity, and immediately with the activation, you can see that the male begins to groan/sing as if he were with a female and at the same time tries to mount the other male as long as this neuronal network is activated by the light).
Prof. Anderson took it one step further and activated the mating network when a toy mouse was nearby. Once again, activating this network caused the male to try to mate, this time with the toy mouse! The video is here.
This is far from being everything, you can use this switch to change war to love! Here, he put a male mouse in a cage of aggressive and territorial male mice and as expected, the new male was immediately attacked, but then Dr. Anderson activated the switch within the attacker's brain and.. the attacking mouse began to sing to the new (white) mouse and tried to make love with him instead of tearing him to pieces. Well, to be precise, making love is when there is mutual desire, but here we see that the white male was not enthusiastic about cooperating.
Similarly, it was found that activation of the second network, which causes violence, will cause the male to attack anything (2), not just another male but also a female (which males rarely attack) and even... just an inflated glove. (Gloves are abundant in laboratories and therefore were the most available object in the environment).
Okay, you got the point... So here's a surprise: the switch for male sexual behavior is also present in females! In other words, females have a neuronal network for male sexual behavior that usually does not come to play but can be activated and cause females to mount a male! Normally, female sexual behavior during mating involves a body position called lordosis in which the back is curved and that allows the male to penetrate. The thing is that when Prof. Anderson activated in females the same neuronal network that causes males to mount, they behaved exactly like males: instead of assuming the lordosis position, they mounted the nearby surprised male! In other words, females have an embedded neuronal network for male sexual behavior that usually does not come to expression. See that in the movie yourself: as soon as the laser is activated, the roles are reversed and the male who until then mounted the female, is suddenly mounted by the other female. By the way, Prof. Tali Kimchi from the Weizmann Institute of Science, when she worked with Prof. Catherine Dulac at Harvard, similarly showed that adult female mice have a neural network for male behavior that is usually not expressed. This network exists in females in a dormant state. Under certain conditions, the male-behavior network can be expressed and the female will start to behave sexually like a male. This was also published in Nature in 2007 (3).
It is unknown if these findings are also true for humans. Do women, like mice, have a neural network for male behavior that is usually not expressed? Do men have a dormant neural network for female behavior? This is like an inner male/female in each of us. Answering these questions in humans is much more difficult, but I believe ways will be found.
How to control violent behavior?
So far I have told you that in mice violence and sexual passion (the desire to have sex with whatever is around) are controlled by two adjacent neuronal networks. Moreover, these two networks inhibit each other: activation of one of them inhibits the other. It's still unknown how does the brain decide which of them to activate at a given time.
In many animal species, males become very aggressive towards other males in the presence of females, but at the same time they do not attack the females (although in the animal kingdom they also do not show tenderness towards them nor they let them control the timing of the mating. In fact, sexual relations are often not pleasurable for females, and that will be discussed in a separate post). The female mouse is protected from being attacked by the male in part by secreting a pheromone, a material that the males sniff and it suppresses their violent behavior. In humans, such a pheromone is not known to exist.
In humans, sexual and non-sexual violence is a difficult social problem. Prof. Anderson has actually identified a group of nerve cells that can be silenced in order to get less violent behavior. The question is how to specifically silence the war cells in violent people? One way could be to make-love because the activation of the love-making network suppresses the make-war network. But unfortunately we can't make love the whole time.. Prof. Anderson suggests an alternative: He found that cells in these two neural networks are different from other cells in their environment in that they react to estrogen. Estrogen is commonly known as the female hormone, but in fact, it is produced from Testosterone and serves males and females for many activities. It appears that one of these activities is lowering the threshold for activation of the neural network in the hypothalamus that leads to an attack.
Therefore, a possible direction for treating people with severe violence problems is to reduce the influence of estrogen. This is something we know how to do and is done by drugs to prevent breast cancer. However, it cannot be patented, so private companies have no business incentive to invest hundreds of millions of dollars in developing this direction as an anti-violence drug. (However, the prediction from here is that people that receive drugs to reduce estrogen as part of anti cancer therapy would be less violent). Additionally, it is not clear how specific this treatment will be: the second neural network, which leads to mating, also reacts to estrogen. Thus, lowering estrogen may reduce mating behavior as well. In mice though, it seems that the dominant effect of reducing estrogen is reducing violence. I assume that over time, something will be found that distinguishes the two neural networks (the war and the desire networks) so that it will allow reducing violence in humans. In the meantime, there have been cases of extremely violent murderers and pedophiles who had a tumor in areas related to violence. After the tumor was removed, the violence or pedophilia disappeared. Of course, this raises questions of responsibility and choice. How frequent is brain abnormality in such murderers and pedophiles is unknown.
That's all for this time about desire and violence in the brain. Thanks for your time and I hope you enjoyed reading!
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