Enabling the future. Prospective action representations in the human parieto-frontal motor planning system

Abstract

One of the primary functions of the central nervous system is to make the body move. Whenever we try to find a mating partner, hunt for food or avoid becoming it ourselves, we need to move. No wonder then, that how does a voluntary movement emerge from brain activity has been one of the most extensively studied problems in neuroscience. But, even despite the research effort, the exact mechanisms are still far from understood. In my dissertation I scrutinize a portion of the complex system responsible for transforming thoughts into actions. Specifically, I focus on the interplay between the cognitive and the motor components of action plans and their representations in posterior parietal and premotor cortex. In the first chapter I start by bringing up the psychological theories of how are the mental representations related to motor actions. Next, I briefly review the current state of knowledge about neural correlates of action planning in the primate brain. I concentrate on hand movements as they pose the major challenge in understanding the motor system, being the most complex type of actions the human body is capable of. After having built this general background, I present my own work, where I try to answer three questions about parieto-frontal processing in action planning: 1) Does the brain visually simulate action effects in prior to action execution? 2) Are the reach trajectory plans organized along one, common neural pathway? 3) Are working memory processes modulated by effector preparation? In the final part of the dissertation I summarize my findings and briefly reflect upon the tangled relationship between the ability to represent and realize ideas, and how it might have shaped the evolution of other remarkable features of the human mind.