Feeling aggressive? You’re not alone.

Last weekend, I was assaulted on the street in broad daylight. I was walking on the sidewalk and a woman crossed the street to come and yell at me for no reason. In more colorful language than I am willing to write here, she told me to get out of there, spit at me and attempted to hit me with her backpack. No one noticed and I had no choice but to keep walking and trying to stop my hands from shaking.

So perhaps it is not surprising that when I opened Nature Neuroscience this week, this article caught my attention.

In this article, the authors compare aggressive behaviors across rodents, songbirds and humans and explain the brain circuits underlying these behaviors. I was quite surprised to find out that the term “aggression” specifically refers to “hostile behaviors toward other animals of the same species”. I guess violence against another species would count as either hunting or self-defense.

In this article, the authors compare aggressive behaviors across rodents, songbirds and humans and explain the #brain circuits underlying these behaviors. #neuroscience #blog

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Similar to almost any behavior, aggression consists of 3 stages: 1) a sensory trigger or input; 2) change of internal state or action taken; and 3) the resulting outcome. Specific aspects of all of these stages vary widely across species:

Interestingly, only humans consider aggression to be “bad behavior”, with learned morals and laws overcoming natural instincts. On the other hand, humans are the only species that show proactive aggression without a valid trigger and can do so with “extreme sophistication, with war as an ultimate example”.

Humans are the only species that show proactive aggression without a valid trigger. #neuroscience

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While there are substantial differences in brain circuits that regulate aggressive behaviors across species, the basic social behavior network (SBN) is the same. The circuit consists of sensory inputs, such as smell for mice and sounds for birds; followed by processing in the core aggression circuit (CAC); resulting in a physical response. Both mice and birds are particularly sensitive to an intruder entering their territory. While mice often proceed directly to pushing or biting their assailant, birds will often first try to solve a conflict by giving a “soft song” warning. And humans… Well, humans are much less predictable.

Interestingly though, humans have one large advantage. We have a much larger and better developed prefrontal cortex (PFC) that provides us with “top down” control of the CAC and allows us to suppress aggression.

Besides cultural norms, humans realize that aggression can be risky and use the executive functions of their PFC to evaluate the situation. In fact, imaging studies show positive correlation between PFC activity and self-imposed control.

So what is the punchline (pun intended)? Brain is like a muscle – the more we practice things like self-control, the better we become. And that allows us to function as part of modern day society.

Reading this article made me think of my work “The Void”. While it was initially meant to represent inner emptiness, given its sole use of red color on black background, it could also represent anger.

But those of us who exercise our prefrontal cortex, often end up turning our anger back inwards, where it may turn into melancholy and depression.