Brain Science at the Century’s Ebb
This chapter highlights some of the major contributions to knowledge of brain function, especially those that reveal some general propositions. The vast majority believe in physical realism and in the general idea that no nonphysical agent in the universe controls or is controlled by brains. Things mental, indeed minds, are emergent properties of brains. Brains contain two major classes of cells. Neurons are the active signaling elements of the brain. Glial cells which equal or exceed neurons in numbers, do not transmit signals but serve a number of other functions. The brain is a system of complexly interconnected neurons organized into local microcircuits, which are then linked into distributed systems. The intracellular injection of molecular markers has established the specificity of neuronal cell types in the cerebral cortex and other regions of the brain, allowing direct correlation of their functional, biochemical, and morphological properties.