The prefrontal cortex has long been suspected to play an important role in cognitive control, in the ability to orchestrate thought and action in accordance with internal goals. Its neural basis, however, has remained a mystery. Here, we propose that cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of (...) activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task. We review neurophysiological, neurobiological, neuroimaging, and computational studies that support this theory and discuss its implications as well as further issues to be addressed. (shrink)

The book examines theories (models) of how systems (those of humans, nature, and combined humannatural systems) function, and attempts to understand those theories and how they can help researchers develop effective institutions and policies for environmental management. The fundamental question this book asks is whether or not it is possible to get beyond seeing environment as a sub-component of social systems, and society as a sub-component of ecological systems, that is, to understand human-environment interactions as their own unique system. After (...) examining the similarities and differences among human and natural systems, as well as the means by which they can be accounted for in theories and models, the book examines five efforts to describe human-natural systems. The point of these efforts is to provide the means of learning about those systems so that they can be managed adaptively. The final section of the book uses case studies to examine the application of integrated theories/models to the real world. (shrink)