The Disordered Mind summary

Did you know that most of us can read minds? Well, at least our brains pretend we can.

Because humans are social creatures, our brains learn to attribute thoughts and emotions to others nearly automatically. Around the age of three, most children begin to understand that the people around them have a mind of their own. This theory of mind, as psychologists call it, helps them understand and predict other people’s behavior, and allows them to navigate the social world quickly and efficiently. For children with autism, however, these things are neither easy nor automatic.

Emotions are a big part of how we experience the world. They help us connect with others, recognize our desires, and make judgement calls when reason alone won’t suffice. When the emotional system in our brains goes haywire, it can cause a great deal of suffering.

In mental disorders like PTSD or depression, the brain gets stuck in a loop of extremely negative emotions, causing a permanently low mood or extreme mental anguish. Unfortunately, such disorders affect nearly one-third of Americans at least once in their lives – making understanding and treating them all the more important.

Of all the mental disorders, schizophrenia might still be the most stigmatized. That’s because it affects a wide range of brain regions, and thus causes dramatic effects on thinking and behavior.

For one, people with schizophrenia often experience visual and auditory hallucinations and paranoid delusions. They may believe that someone is sending them special messages, or that other people are out to get them. But schizophrenia also comes with less obvious symptoms such as social withdrawal, lack of motivation, and memory problems.

Henry Molaison, known to his doctors only as H.M., is one of the most important patients in the history of neuroscience. Like many of them, he wasn’t a particularly lucky guy. After injuring his head in a bike accident as a child, H.M. began suffering from severe epilepsy as an adult. To stop the seizures, his doctors decided to take out the parts of the brain that had been scarred in the accident.

The operation swiftly cured H.M.’s epilepsy, but it came at a high price: H.M. still remembered people and events from many years ago, but he could no longer form new memories. Every new piece of information he learned after the operation he immediately forgot. Surprisingly, researchers found that he could still learn new motor tasks like learning new drawing skills – he just didn’t remember practicing.

Dementia and Alzheimer’s aren’t the only neurological disorders caused by misfolding proteins. Since there are countless different proteins in the human brain, there are countless ways in which faulty proteins can affect our thoughts and behavior. In Parkinson’s and Huntington’s disease, for instance, misfolding proteins in the brain slowly erode a person’s ability to move.

Here’s the key message: Parkinson’s disease reveals the role of brain chemicals in movement.

Not too long ago, even psychologists believed that addiction was simply a matter of willpower. When a pleasurable behavior becomes so destructive it ruins your health and relationships, why not just stop it? Thanks to the insights of neuroscience, we know now that things are not that simple.

Like other mental disorders, addiction – whether to drugs, alcohol, gambling or eating – fundamentally changes our brains. It primarily acts on the systems involved in pleasure, emotions, and behavior, virtually robbing us of our will. This comes at a massive cost: the power of addictions costs the US economy an estimated 740 billion dollars a year.

In most species, male and female animals show clear differences in behavior. Humans are no exception, though we show much greater range and variety in gendered behavior than other species.

Nonetheless, neuroscientists have discovered subtle structural and molecular differences in the brains of men and women. Gender-specific activity patterns occur in areas related to sexual and reproductive behaviors, for example, but also in regions involved in emotion, memory, and stress. We don’t know yet how these patterns translate into thought and behavior, but it appears that sex and gender also express themselves in the brain.

Of all the complex mental states the brain produces, consciousness is one of its most puzzling features.

In simple terms, being conscious means being aware of our mental processes as they happen. When we’re awake, experiences such as seeing a friendly face, smelling a rose, or being afraid have a subjective quality that we can think and talk about later.