Hjernebark og syntaktiske træer

Abstract

The syntax of human language is a recursive, generative system. Both of these properties are ubiquitous in the natural world. In fact, sentences, trees, and brains share the property of hierarchical structure (i.e., tree-structure) as a fundamental principle. Aspects of syntax are subject to general constraints on structure which in themselves have no meaning. In contrast, the way we use and manipulate these structures (usually) are meaningful. Another parallel between trees and brains is that they both have bark, in the brain called cortex. I argue that the activation in the "bark" of the brain depends on the nature of the syntactic tree, that is, structural properties of any given sentence. I present results from two neuroimaging studies on sentence comprehension which also provide support for a much more distributed implementation of language in the brain than is usually assumed, especially in neuropsychology textbooks. In particular, comprehension phenomena at the interface between syntax and pragmatics (i.e., between form and function) engage Broca’s area (often called the speech area), whereas purely structural differences in syntactic form engage motor and premotor cortex. Language is a complex system of subsystems (or modules) implemented in the brain as distributed and overlapping networks.