The organization of neocortex in mammals: implications for theories of brain function.

INTRODUCTION............................................................ ......................... 129 TRADITIONAL ARCHITECTONIC THEORIES OF CORTICAL ORGANIZATION ....................................................................... 130 DEFINING FIELDS BY M ULTIPLE CRITERIA.............................................. 132 CURRENT CONCEPTS OF CORTICAL ORGANIZATION ................................ 136 Cortical Areas Are Sharply Defined .................................................. . . ...... 136 Cortical Areas Are Functionally Heterogeneous.................................... . . . ..... 137 Species Vary in Number of Areas ........................... .................................. 139 All Mammals Have Some Fields in Common .............................. ................. 139 Major Advances in Brain Evolution Have Been Marked by Increases in Numbers of Unimodal Sensory Areas........ ................. . .............. 142 Areas Are Multiply Interconnected; Connections Are Species-Variable.. . . . ... . . . . . . . . 142 Detailed Organization Is Dynamically Maintained....... . .................... . ............ 144 Self-Organization Occurs During Development ............................................. 145 CONCLUSIONS.......... ... .......................... .................................... ............ 147