Relative Hierarchies and the Representation of Action

Abstract

Hierarchy is a central concept for understanding how complex goal-oriented behaviors are organized. In this chapter we present recent functional and behavioral evidence that supports the existence of a control hierarchy in the human brain for organizing complex motor. It is proposed that the functional hierarchy is not based on strict anatomical connectivity within the motor system. Instead, there are multiple motor planning circuits, each of which can serve a supraordinate role, and this role can be readily interchanged to achieve a much wider range of task outcomes. This can be observed at the level of hand-object interactions, bimanual control, and the integration of semantics into action planning.