THE DISORDERED MIND

The eminent neuroscientist examines what the injured or diseased brain can tell us about a healthy one.

“Today, as never before, the study of brain disorders is giving us new insight into how our mind normally functions,” writes Nobel Prize winner Kandel (Neuroscience/Columbia Univ.; Reductionism in Art and Brain Science: Bridging the Two Cultures, 2016, etc.). That “normal function” is a complex process involving many parts of the brain, reflecting the emergent fact that consciousness is not a single function of the brain but instead a continuum of “different states of minds in different contexts.” Complex cognitive skills such as understanding speech require input from several widely separated areas of the brain, including the arcuate fasciculus and Broca’s area, while the generation and execution of emotion involve the hypothalamus, striatum, prefrontal cortex, and one tiny part of the brain whose functions are just being understood: “When we laugh or cry—when we experience any emotion—it is because these brain structures are responding to the amygdala, and acting on its instructions.” But just so, writes Kandel, problems such as addiction also involve several brain regions and neural circuits, requiring multiple approaches to any neuroscientific regime of treatment. Autism is another such area, manifesting itself in failures in the complex problem of interpreting “biological motion,” which in turn “enables us to recognize intention, which is critical to a theory of mind.” In the end, understanding various states of brain function in varying degrees of health helps address not just the question of consciousness, modern theories of which Kandel addresses in closing, but also the much larger issue of human nature and what it entails. Throughout, the author writes accessibly, though it may help readers to have some background in neuroscience and anatomy.

Synaptic pruning, folded proteins, adaptive habits: all fascinating stuff ably interpreted by a master.