Karl Deisseroth is best known for contributing to the invention of optogenetics, for which he just won the Lasker Award, and a lot of people think will win him a Nobel Prize. The technique features a lot in the book, but he writes mainly from the perspective of a psychiatrist and each of the 7 chapters is presented as a case study that explores some aspect of the human mind. Throughout he weaves together compelling and poetic narratives about case studies with some of the most fundamental questions in neuroscience.
From the other Goodreads reviews, it seems like the prose of the book makes it a little contentious. To some, it comes across as poetic and moving. To others, it comes across as try-hard and pretentious. I was much more in the first category. I had to read the book more slowly than usual, but I also felt my emotions being carried along by the book much more than usual (especially in non-fiction).
Throughout the book, Deisseroth addresses some of the biggest questions in neuroscience:
If evolutionary advantages only depend on actions, why do we even have feelings?
Can you build some real "theory of responsibility of action" by determining the degree that different brain activity can be controlled or altered by the prefrontal cortex?
If remembering is through reactivating a neural pattern, where is the memory when it is not actively remembered?
Can you control all experience through neural firing? The answer seems absurd in both directions. To answer 'no' means that something outside of the brain must be involved. To answer 'yes', it seems like we should be able to separate neurons to different locations around the globe and stimulate them with precise time to generate the same experience, which seems absurd.
Why is consciousness so slow? How is this 1/4 second delay compatible with our everyday experience of a fluent face-to-face conversation?
One of the biggest themes of the book for me was this idea of trade-offs. That there are advantages and disadvantages to competing traits, and so most of us fall on a spectrum of those dimensions. This idea was combined with the metaphor of sickle-cell anemia, where heterozygotes have protection against malaria, but homozygotes for the recessive gene have a disease. Maybe some extreme disorders are too much of one thing and not enough of the balancing thing, so to speak.
Chapter 1 is called "Storehouse of Tears". It explores the case study of a man who, faced with incredible loss, has the primary complaint that he cannot cry. Deisseroth introduces some general themes of the book in this chapter that pop up over and over again throughout the book. He introduces the tool of thinking about emotional states through the lens of evolution, but also about how it's sometimes tricky to do this, since there may be some founder's effects in the human gene pool due to some close calls with extinction. Crying itself may be one of these weird human quirks. We're the only ape (and animal apparently) to do emotional crying. He proposes how it might be beneficial to have new automatic expressions of emotions in a social species because at the individual level, we benefit by deceiving everyone, but at the group level, we benefit through information sharing.
Chapter 2 is called "First Break," and is about a man who becomes manic for the first time after retirement. After 9-11, he fixates on an emotional image of a father and a daughter on one of the planes from his own imagination, and this seems to somehow push him into an extreme manic state. He doesn't need to sleep and is highly motivated. His is forced into treatment despite not wanting it himself, which he still does not feel was necessary even after treatment, so the chapter focuses some of its discussion on the ethics of this type of situation. Deisseroth makes connections between this man and Joan of Arc, with their same militant and righteous convictions and extreme motivational energy in response to a foreign invader.
Chapter 3 is called "Carrying Capacity," and tells the remarkable story of a socially adept Uygur women telling the story of her husband's interment. Deisseroth contrasts her amazingly rich and textured story-telling and social skill with the overwhelming stimulation of social information in autism. Deisseroth considers that for humans, there are uses for dealing with situations with extreme dynamical complexitiy as in social encounters, but other uses for situations where you want to spend a lot of time focusing on fixed objects with unchanging rules. In the human genome, perhaps genes directing these attributes are competing is some way.
Chapter 4 is called "Broken Skin," and is about a man with borderline personality disorder and the strange relief of cutting in certain disorders. Deisseroth also explores the notions of borders and self-hood through the sensors on the skin.
Chapter 5 is called "The Faraday Cage," and is told from the perspective of a psychotic patient who may have schizophrenia. The story told this way gives the reader the fascinating perspective of the flow of thought from the psychotic patient. There are some interesting conversations between the patient and Karl Deisseroth exploring the idea that belief is itself controlled by the brain and can be fixed or loose. What we think seems so true is just a shared belief.
Chapter 6 is called "Consummation," and tells the story of a young woman with an eating disorder and discusses how the human mind is capable of overcoming the brain's most primitive drives of hunger.
Chapter 7 is called "Moro," which refers to a startle reflex that exists in babies, goes away around 3-6 months of age, but then can reappear in cases of severe brain damage, indicating that it has existed the whole time, but laid dormant, inhibited by the rest of the cortex. This chapter is mostly about the aging and anhedonia, and how we may feel the absence of joy through accompanying reduced brain activity that occurs with dementia.