Neural Science : Review A Century of Progress

San Diego, California 92186 largest sense, these studies revealed that all mental †Howard Hughes Medical Institute processes, no matter how complex, derive from the and Center for Neurobiology and Behavior brain and that the key to understanding any given mental Department of Biochemistry and Molecular Biophysics process resides in understanding how coordinated sigCollege of Physicians and Surgeons naling in interconnected brain regions gives rise to beof Columbia University havior. Thus, one consequence of this top–down analyNew York, New York 10032 sis has been initial demystification of aspects of mental ‡Sackler Institute function: of language perception, action, learning, and Department of Psychiatry memory (Kandel et al., 2000). Weill Medical College of Cornell University A second consequence of the top–down approach New York, New York 10021 came at the beginning of the twentieth century with the