This chapter bridges Part 1 and the interpretations that Damasio offers in later chapters. In addition, it offers a dense overview of relevant anatomical terms and their known functions.

Throughout Descartes’ Error, Damasio defines the “body” as the organism minus its neural tissue (the central and peripheral nervous systems). The “organism” itself comprises a myriad of components working together to ensure its integrity. A tissue forms its boundary, and it moves via muscles and joints. Damasio refers to the body’s organs as its “viscera”—except for the brain, which he excludes from that definition for clarity’s sake. The brain is composed of cells in operation and has an incredibly complex structure.

The organism is in a constant state of change. Its condition, or image, at a specific point in time is a “body state” or “mind state.” The body and mind interconnect via two principal mechanisms. The first takes shape in the peripheral nerves, which fire signals from the body to the brain and vice-versa. The second is through the bloodstream, which came first in evolution and carries chemical information such as hormones, neurotransmitters, and modulators. Both brain and body can control the circulation of chemical or neural information.